Science.gov

Sample records for cutting edge imaging

  1. Cutting Edge Imaging of THE Spine

    PubMed Central

    Vertinksy, A. Talia; Krasnokutsky, Michael V.; Augustin, Michael; Bammer, Roland

    2007-01-01

    Damage to the spinal cord may be caused by a wide range of pathologies and generally results in profound functional disability. Therefore, a reliable diagnostic workup of the spine is very important because even relatively small lesions in this part of the central nervous system can have a profound clinical impact. This is primarily due to the dense arrangement of long fiber tracts extending to and from the extremities within the spinal cord. Because of its inherent sensitivity to soft tissues and its capability of displaying long segments of the vertebral column in one examination, MRI has become the method of choice for the detection and diagnosis of many disorders in the spine. A variety of innovative MRI methods have been developed to improve neuroimaging. Nevertheless, the application of these new methods to the spinal cord is, compared to its cephalad cousin, still not used that frequently. These techniques include the development of better pulse sequences and new MR contrast parameters that offer a wider spectrum of biophysical parameters in deriving a diagnosis. Overall, these new “cutting-edge” technologies have the potential to profoundly impact the ease and confidence of spinal disease interpretation and offer a more efficient diagnostic work-up of patients suffering from spinal disease. PMID:17493543

  2. Root dentine and endodontic instrumentation: cutting edge microscopic imaging

    PubMed Central

    2016-01-01

    Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation—by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments. PMID:27274802

  3. Root dentine and endodontic instrumentation: cutting edge microscopic imaging.

    PubMed

    Atmeh, Amre R; Watson, Timothy F

    2016-06-06

    Cutting of the dental hard tissues is an integral part of restorative dentistry. Cutting of the root dentine is also needed in preparation prior to endodontic treatment, with significant commercial investment for the development of flexible cutting instruments based around nickel titanium (NiTi) alloys. This paper describes the evolution of endodontic cutting instruments, both in materials used, e.g. the transition from stainless steel to NiTi, and the design of the actual instruments themselves and their method of activation-by hand or motor driven. We have been examining tooth-cutting interactions microscopically for over 25 years using a variety of microscopic techniques; in particular, video-rate confocal microscopy. This has given a unique insight into how many of the procedures that we take for granted are achieved in clinical practice, by showing microscopic video images of the cutting as it occurs within the tooth. This technology has now been extended to allow imaging of the endodontic instrument and the root canal wall for the first time. We are able to image dentine distortion and crack propagation during endodontic filing of the root canal space. We are also able to visualize the often claimed, but seldom seen action of contemporary endodontic instruments.

  4. Cutting-edge digital storage for portable imaging systems

    NASA Astrophysics Data System (ADS)

    Kimball, Richard

    1995-08-01

    Currently, most portable digital imaging systems use standard 3.5 inch floppies for storage of images and data. Driven by an increasing demand for smaller, lighter, lower power devices, the space restrictions for a digital storage device have become more severe. One solution is to provide a separate device containing the floppy drive, with its own power source, connected to the imaging system with external cables. A better method is the use of PCMCIA memory cards. PCMCIA (Personal Computer Memory Card International Association) memory cards have many advantages over floppy drives. They are smaller, more rugged, faster, and require less power. PCMCIA memory cards can be formatted to accept DOS files, making it easy to move files to a PC for archiving and image processing. Including a PCMCIA socket and controller circuitry in an imaging system provides a convenient upgrade path for future capabilities. The problems associated with adding PCMCIA memory card storage to a portable imaging system are formidable, however. There is little or no off-the-shelf software to support these cards in an embedded system. Since it is a relatively new technology, there is very little public, practical knowledge to guide the embedded systems designer. The PCMCIA standards are lengthy and complicated, and still changing. Memory card technology is changing and card prices are still much higher than for floppies. These and other issues were encountered on a recent development project at Inframetrics. This paper discusses how these issues were addressed and assesses where PCMCIA is headed.

  5. Neural network approach for automatic image analysis of cutting edge wear

    NASA Astrophysics Data System (ADS)

    Mikołajczyk, T.; Nowicki, K.; Kłodowski, A.; Pimenov, D. Yu.

    2017-05-01

    This study describes image processing systems based on an artificial neural network to estimate tool wear. The Single Category-Based Classifier neural network was used to process tool image data. We present a method to determine the rate of tool wear based on image analysis, and discuss the evaluation of errors. Using the proposed algorithm, we made in Visual Basic the special Neural Wear software for analysis of the worn part of the cutting edge. For example, the image of worn edge was created determining the optimum setting of Neural Wear software to automatically indicate the wear area. The result of the analysis was the number of pixels that belonged to the worn area. Using these settings, we made an image analysis of edge wear for different working times. We used the calculated parameters of correlation between the number of pixels and VB index. Our results promise a good correlation between the new methods and the commonly used optically measured VB index, with an absolute mean relative error of 6.7% for the tools' entire life range. Automatic detection of wear of the cutting edge can be useful in many applications; for example, in predicting tool life based on the current value of edge wear.

  6. The Landsat Image Mosaic of Antarctica (LIMA): A Cutting-Edge Way for Students and Teachers to Learn about Antarctica

    ERIC Educational Resources Information Center

    Campbell, Brian; Bindschadler, Robert

    2009-01-01

    By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our…

  7. The Landsat Image Mosaic of Antarctica (LIMA): A Cutting-Edge Way for Students and Teachers to Learn about Antarctica

    ERIC Educational Resources Information Center

    Campbell, Brian; Bindschadler, Robert

    2009-01-01

    By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our…

  8. Quantum dot-based image sensors for cutting-edge commercial multispectral cameras

    NASA Astrophysics Data System (ADS)

    Mandelli, Emanuele; Beiley, Zach M.; Kolli, Naveen; Pattantyus-Abraham, Andras G.

    2016-09-01

    This work presents the development of a quantum dot-based photosensitive film engineered to be integrated on standard CMOS process wafers. It enables the design of exceptionally high performance, reliable image sensors. Quantum dot solids absorb light much more rapidly than typical silicon-based photodiodes do, and with the ability to tune the effective material bandgap, quantum dot-based imagers enable higher quantum efficiency over extended spectral bands, both in the Visible and IR regions of the spectrum. Moreover, a quantum dot-based image sensor enables desirable functions such as ultra-small pixels with low crosstalk, high full well capacity, global shutter and wide dynamic range at a relatively low manufacturing cost. At InVisage, we have optimized the manufacturing process flow and are now able to produce high-end image sensors for both visible and NIR in quantity.

  9. Cutting edge imaging of human cochlea by industrial high resolution computed micro tomography

    NASA Astrophysics Data System (ADS)

    Fischer, Björn; Krüger, Peter; Poznyakovskiy, Anton A.; Zahnert, Thomas

    2012-03-01

    Validation of statistically confirmed geometrical models of the human inner ear requires precise image data of bony structures and soft tissue. By optimization and application of our Industrial High Resolution Micro Computer Tomograph (microCT, Fraunhofer IZFP), we achieve an image quality known so far only from synchrotron X-ray tomography. To improve the generation of X-ray photons, the micro focus X-ray tube was equipped with a high performance transmission target with diamond carrier to achieve a higher photon flux at the same focal diameter. Additionally, our new alignment tool allows post-acquisition correction of adjustment incorrectness which plays a key role in reconstruction of high resolution microCT-data. However, an accurate segmentation of the cochlea is still problematic due to the low X-ray absorption contrast of the inner membranes of scalae. To solve this problem, the soft tissue was stained by putting the specimen into an iodine solution. The resulting data are of outstanding quality and provide the basin for an extensive anatomical study and further development of statistical geometrical models of the human inner ear.

  10. Auditing to the cutting edge

    SciTech Connect

    Good, L.; Wirdzek, P.

    1999-07-01

    Equipment? System? Building? Campus? Neighborhood? Community? Region? What is to be audited and what needs to be corrected? Can the energy management professional decide, or should the customer? Over the last few decades, energy professionals have been evaluating energy use in order to balance clients' expenditures with acceptable levels of service. Traditionally, professional expertise and creativity have been limited more by budget than any other single element. Today, energy and the environment are tightly intertwined. In the future, effective energy management may not be possible without considering the relationships between them. Conversely, environmental protection cannot be achieved without considering energy production, distribution, and use. To this end, two powerful federal organizations, the US Environmental Protection Agency (EPA) and the US Department of Energy (DOE), have been engaged in defining the interrelationships of these areas and fashioning national energy policies aimed at awakening Americans to these facts. Environmental demands are becoming a factor in efficiency equations. Energy management professionals should prepare a response. They will face demands for cutting-edge audits that reach further than giving utility power just a trim in the energy barber shop. Survival in the business of energy management will require a broader perspective. One need only look to current advertisements by national and international corporations which praise the environmental benefits of their products and even their places of business as cleaner than their competitors'. For the energy management professional then, energy diversity and source versus site considerations are opportunities to be identified in the audit process, in addition to replacement of inefficient equipment. The country is rich with technology choices, with documented experience, and with the knowledge to create systems that can mine deep savings. True, some have niche applications, which

  11. The Cutting-Edge Challenge

    ERIC Educational Resources Information Center

    Share, Joani

    2005-01-01

    In a time of educational budget cuts, the arts seem to take the major brunt of the financial ax. Fine arts programs are often pitted against one another for survival. The music industry and supporting corporations, such as American Express, campaign to have instruments donated or purchased to keep educational programs alive. The visual arts do not…

  12. The Cutting-Edge Challenge

    ERIC Educational Resources Information Center

    Share, Joani

    2005-01-01

    In a time of educational budget cuts, the arts seem to take the major brunt of the financial ax. Fine arts programs are often pitted against one another for survival. The music industry and supporting corporations, such as American Express, campaign to have instruments donated or purchased to keep educational programs alive. The visual arts do not…

  13. The Cutting Edge, 1999-2000.

    ERIC Educational Resources Information Center

    Cutting Edge, 2000

    2000-01-01

    The Cutting Edge is a bimonthly newsletter of the Regional Center for Applied Technology and Training at Danville Community College (DCC) (Virginia) that provides the latest information on a wide range of issues including technology, business, employment trends, and new legislation. Articles from the first five issues discuss: (1) the July 2000…

  14. The Cutting Edge: Workplace English. Instructional Guide.

    ERIC Educational Resources Information Center

    El Paso Community Coll., TX. Literacy Center.

    The instructional guide for the Cutting Edge workplace literacy program, a cooperative project of El Paso Community College (Texas) and Levi Strauss and Company, is an expanded version of one appendix the project handbook. It describes and provides an instructional model for the three-part, job-specific, video-based program of English as a Second…

  15. Protease signalling: the cutting edge

    PubMed Central

    Turk, Boris; Turk, Dus̆an; Turk, Vito

    2012-01-01

    Protease research has undergone a major expansion in the last decade, largely due to the extremely rapid development of new technologies, such as quantitative proteomics and in-vivo imaging, as well as an extensive use of in-vivo models. These have led to identification of physiological substrates and resulted in a paradigm shift from the concept of proteases as protein-degrading enzymes to proteases as key signalling molecules. However, we are still at the beginning of an understanding of protease signalling pathways. We have only identified a minor subset of true physiological substrates for a limited number of proteases, and their physiological regulation is still not well understood. Similarly, links with other signalling systems are not well established. Herein, we will highlight current challenges in protease research. PMID:22367392

  16. Protease signalling: the cutting edge.

    PubMed

    Turk, Boris; Turk, Dušan; Turk, Vito

    2012-04-04

    Protease research has undergone a major expansion in the last decade, largely due to the extremely rapid development of new technologies, such as quantitative proteomics and in-vivo imaging, as well as an extensive use of in-vivo models. These have led to identification of physiological substrates and resulted in a paradigm shift from the concept of proteases as protein-degrading enzymes to proteases as key signalling molecules. However, we are still at the beginning of an understanding of protease signalling pathways. We have only identified a minor subset of true physiological substrates for a limited number of proteases, and their physiological regulation is still not well understood. Similarly, links with other signalling systems are not well established. Herein, we will highlight current challenges in protease research.

  17. Cutting edge issues in autoimmune gastritis.

    PubMed

    Toh, Ban-Hock; Chan, James; Kyaw, Tin; Alderuccio, Frank

    2012-06-01

    Autoimmune gastritis is the outcome of a pathological CD4 T cell-mediated autoimmune response directed against the gastric H/K-ATPase. Silent initially, the gastric lesion becomes manifest in humans by the development of megaloblastic pernicious anemia arising from vitamin B12 deficiency. Cutting edge issues in this disease relate to its epidemiology, immunogenetics, a role for Helicobacter pylori as an infective trigger through molecular mimicry, its immunopathogenesis, associated organ-specific autoimmune diseases, laboratory diagnosis, and approaches to curative therapy.

  18. Imaging, cutting, and collecting instrument and method

    DOEpatents

    Tench, Robert J.; Siekhaus, Wigbert J.; Balooch, Mehdi; Balhorn, Rodney L.; Allen, Michael J.

    1995-01-01

    Instrumentation and techniques to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution, to cut-off identified parts of such objects, to move around and manipulate such cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM, such that plural cantilevers are used with either sharp-tips or knife-edges thereon. In addition, the invention can be utilized for measuring hardness of materials.

  19. GSFC Cutting Edge Avionics Technologies for Spacecraft

    NASA Technical Reports Server (NTRS)

    Luers, Philip J.; Culver, Harry L.; Plante, Jeannette

    1998-01-01

    With the launch of NASA's first fiber optic bus on SAMPEX in 1992, GSFC has ushered in an era of new technology development and insertion into flight programs. Predating such programs the Lewis and Clark missions and the New Millenium Program, GSFC has spearheaded the drive to use cutting edge technologies on spacecraft for three reasons: to enable next generation Space and Earth Science, to shorten spacecraft development schedules, and to reduce the cost of NASA missions. The technologies developed have addressed three focus areas: standard interface components, high performance processing, and high-density packaging techniques enabling lower cost systems. To realize the benefits of standard interface components GSFC has developed and utilized radiation hardened/tolerant devices such as PCI target ASICs, Parallel Fiber Optic Data Bus terminals, MIL-STD-1773 and AS1773 transceivers, and Essential Services Node. High performance processing has been the focus of the Mongoose I and Mongoose V rad-hard 32-bit processor programs as well as the SMEX-Lite Computation Hub. High-density packaging techniques have resulted in 3-D stack DRAM packages and Chip-On-Board processes. Lower cost systems have been demonstrated by judiciously using all of our technology developments to enable "plug and play" scalable architectures. The paper will present a survey of development and insertion experiences for the above technologies, as well as future plans to enable more "better, faster, cheaper" spacecraft. Details of ongoing GSFC programs such as Ultra-Low Power electronics, Rad-Hard FPGAs, PCI master ASICs, and Next Generation Mongoose processors.

  20. Research and application of edge detection technology in costume pattern cutting

    NASA Astrophysics Data System (ADS)

    Zhang, Wenming; Qiu, Jianxin

    2009-11-01

    Research and application of edge detection technology in costume pattern cutting. I made a software with Visual C++6.0 to realize contour extraction of costume pattern. It also contains gray balance, Laplace edge detection, image's erosion and so on. Besides, I deeply compared applicability of each algorithm and all combinations of them. In this experiment, I succeed in extracting contour of complex costume patterns. Furthermore, controlling laser-cutting machine cut real costume patterns by software. In conclude that I not only have realized automatic extracting contour and cutting by this software in several minutes but also improved the precision of contour extraction.

  1. Material Behavior At The Extreme Cutting Edge In Bandsawing

    SciTech Connect

    Sarwar, Mohammed; Haider, Julfikar; Persson, Martin; Hellbergh, Haakan

    2011-01-17

    In recent years, bandsawing has been widely accepted as a favourite option for metal cutting off operations where the accuracy of cut, good surface finish, low kerf loss, long tool life and high material removal rate are required. Material removal by multipoint cutting tools such as bandsaw is a complex mechanism owing to the geometry of the bandsaw tooth (e.g., limited gullet size, tooth setting etc.) and the layer of material removed or undeformed chip thickness or depth of cut (5 {mu}m-50 {mu}m) being smaller than or equal to the cutting edge radius (5 {mu}m-15 {mu}m). This situation can lead to inefficient material removal in bandsawing. Most of the research work are concentrated on the mechanics of material removal by single point cutting tool such as lathe tool. However, such efforts are very limited in multipoint cutting tools such as in bandsaw. This paper presents the fundamental understanding of the material behaviour at the extreme cutting edge of bandsaw tooth, which would help in designing and manufacturing of blades with higher cutting performance and life. ''High Speed Photography'' has been carried out to analyse the material removal process at the extreme cutting edge of bandsaw tooth. Geometric model of chip formation mechanisms based on the evidences found during ''High Speed Photography'' and ''Quick Stop'' process is presented. Wear modes and mechanism in bimetal and carbide tipped bandsaw teeth are also presented.

  2. Material Behavior At The Extreme Cutting Edge In Bandsawing

    NASA Astrophysics Data System (ADS)

    Sarwar, Mohammed; Haider, Julfikar; Persson, Martin; Hellbergh, Hâkan

    2011-01-01

    In recent years, bandsawing has been widely accepted as a favourite option for metal cutting off operations where the accuracy of cut, good surface finish, low kerf loss, long tool life and high material removal rate are required. Material removal by multipoint cutting tools such as bandsaw is a complex mechanism owing to the geometry of the bandsaw tooth (e.g., limited gullet size, tooth setting etc.) and the layer of material removed or undeformed chip thickness or depth of cut (5 μm-50 μm) being smaller than or equal to the cutting edge radius (5 μm-15 μm). This situation can lead to inefficient material removal in bandsawing. Most of the research work are concentrated on the mechanics of material removal by single point cutting tool such as lathe tool. However, such efforts are very limited in multipoint cutting tools such as in bandsaw. This paper presents the fundamental understanding of the material behaviour at the extreme cutting edge of bandsaw tooth, which would help in designing and manufacturing of blades with higher cutting performance and life. "High Speed Photography" has been carried out to analyse the material removal process at the extreme cutting edge of bandsaw tooth. Geometric model of chip formation mechanisms based on the evidences found during "High Speed Photography" and "Quick Stop" process is presented. Wear modes and mechanism in bimetal and carbide tipped bandsaw teeth are also presented.

  3. Imaging, cutting, and collecting instrument and method

    DOEpatents

    Tench, R.J.; Siekhaus, W.J.; Balooch, M.; Balhorn, R.L.; Allen, M.J.

    1995-10-31

    Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to move around and manipulate the cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM. The plural cantilevers are used with either sharp-tips or knife-edges. In addition, the invention can be utilized for measuring the hardness of materials. 10 figs.

  4. 7. View of cut stone apron sitting at edge of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. View of cut stone apron sitting at edge of concrete apron. Photograph taken from east side of lower dam. VIEW WEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  5. Information Commons Features Cutting-Edge Conservation and Technology

    ERIC Educational Resources Information Center

    Gilroy, Marilyn

    2011-01-01

    This article features Richard J. Klarchek Information Commons (IC) at Loyola University Chicago, an all-glass library building on the shore of Chicago's Lake Michigan that is not only a state-of-the-art digital research library and study space--it also runs on cutting-edge energy technology. The building has attracted attention and visitors from…

  6. Scaling Community College Interventions. Cutting Edge Series. No. 2

    ERIC Educational Resources Information Center

    Public Agenda, 2011

    2011-01-01

    This is the second guide of the Cutting Edge Series and is designed to help colleges apply strategies that will allow successful institutional change and student achievement initiatives to reach more students. Section 1 of this guide lays out the most common obstacles to successful scaling and serves as a sobering reminder of the complexity of the…

  7. The Community College Baccalaureate Movement: Cutting-Edge Dissertation Research

    ERIC Educational Resources Information Center

    Hrabak, Michael R.

    2009-01-01

    In this review of dissertations, the researcher presents summaries of 10 of the most recent and cutting-edge dissertations focusing on the ever-growing and complex field of the community college baccalaureate movement. These studies focus on the gamut of specific legislation, case studies of particular programs and schools, financing of such…

  8. Information Commons Features Cutting-Edge Conservation and Technology

    ERIC Educational Resources Information Center

    Gilroy, Marilyn

    2011-01-01

    This article features Richard J. Klarchek Information Commons (IC) at Loyola University Chicago, an all-glass library building on the shore of Chicago's Lake Michigan that is not only a state-of-the-art digital research library and study space--it also runs on cutting-edge energy technology. The building has attracted attention and visitors from…

  9. The Community College Baccalaureate Movement: Cutting-Edge Dissertation Research

    ERIC Educational Resources Information Center

    Hrabak, Michael R.

    2009-01-01

    In this review of dissertations, the researcher presents summaries of 10 of the most recent and cutting-edge dissertations focusing on the ever-growing and complex field of the community college baccalaureate movement. These studies focus on the gamut of specific legislation, case studies of particular programs and schools, financing of such…

  10. On the Cutting Edge: Workshops, Online Resources, and Community Development

    NASA Astrophysics Data System (ADS)

    Mogk, D. W.; Macdonald, H.; Manduca, C. A.; Tewksbury, B. J.; Fox, S.; Iverson, E. A. R.; Beane, R. J.; Mcconnell, D. A.; Wiese, K.; Wysession, M. E.

    2014-12-01

    On the Cutting Edge, funded by NSF since 2002, offers a comprehensive professional development program for geoscience faculty. The program includes an annual integrated in-person and virtual workshop series, has developed an extensive collection of peer-reviewed instructional activities and related online resources, and supports continuing community development through sponsorship of webinars, listservs, opportunities for community contributions, and dissemination of resources to keep faculty current in their science and pedagogic practices. On the Cutting Edge (CE) has offered more than 100 face-to-face and virtual workshops, webinars, journal clubs, and other events to more than 3000 participants. The award-winning website has more than 5000 pages including 47 modules on career management, pedagogy, and geoscience topics. It has more than 1800 instructional activities contributed by the community, the majority of which have been peer-reviewed. The website had more than one million visitors last year. We have worked to support a community in which faculty improve their teaching by designing courses using research-based methods to foster higher-order thinking, incorporate geoscience data, and address cognitive and affective aspects of learning as well as a community in which faculty are comfortable and successful in managing their careers. The program addresses the needs of faculty in all career stages at the full spectrum of institutions and covering the breadth of the geoscience curriculum. We select timely and compelling topics that attract different groups of participants. CE workshops are interactive, model best pedagogical practices, emphasize participant learning, provide opportunities for participants to share their knowledge and experience, provide high-quality resources, give participants time to reflect and to develop action plans, and help transform their ideas about teaching. On the Cutting Edge has had an impact on teaching based on data from national

  11. Experiments on airfoils with trailing edge cut away

    NASA Technical Reports Server (NTRS)

    Ackeret, J

    1927-01-01

    Airfoils with their trailing edge cut away are often found on aircraft, as the fins on the hulls of flying boats and the central section of the wings for affording better visibility. It was therefore of some interest to discover the effect of such cutaways on the lift and drag and on the position of the center of pressure. For this purpose, systematic experiments were performed on two different airfoils, a symmetrical airfoil and an airfoil of medium thickness, with successive shortenings of their chords.

  12. At the cutting-edge of grape and wine biotechnology.

    PubMed

    Borneman, Anthony R; Schmidt, Simon A; Pretorius, Isak S

    2013-04-01

    Wine is arguably the oldest biotechnological endeavor, with humans having been involved in wine production for at least 7000 years. Despite the artisan nature of its production, work by pioneering scientists such as Antoine-Laurent de Lavoisier and Louis Pasteur placed wine research in a prominent position for the application of cutting-edge biological and chemical sciences, a position it still holds to this day. Technologies such as whole-genome sequencing and systems biology are now revolutionizing winemaking by combining the ability to engineer phenotypes rationally, with a precise understanding of the genetic makeup and key phenotypic drivers of the key organisms that contribute to this age-old industry.

  13. Growing Cutting-edge X-ray Optics

    SciTech Connect

    Ray Conley

    2012-11-30

    Ever imagined that an Xbox controller could help open a window into a world spanning just one billionth of a meter? Brookhaven Lab's Ray Conley grows cutting-edge optics called multilayer Laue lenses (MLL) one atomic layer at a time to focus high-energy x-rays to within a single nanometer. To achieve this focusing feat, Ray uses a massive, custom-built atomic deposition device, an array of computers, and a trusty Xbox controller. These lenses will be deployed at the Lab's National Synchrotron Light Source II, due to begin shining super-bright light on pressing scientific puzzles in 2015

  14. Growing Cutting-edge X-ray Optics

    ScienceCinema

    Ray Conley

    2016-07-12

    Ever imagined that an Xbox controller could help open a window into a world spanning just one billionth of a meter? Brookhaven Lab's Ray Conley grows cutting-edge optics called multilayer Laue lenses (MLL) one atomic layer at a time to focus high-energy x-rays to within a single nanometer. To achieve this focusing feat, Ray uses a massive, custom-built atomic deposition device, an array of computers, and a trusty Xbox controller. These lenses will be deployed at the Lab's National Synchrotron Light Source II, due to begin shining super-bright light on pressing scientific puzzles in 2015

  15. Edge enhanced morphology for infrared image analysis

    NASA Astrophysics Data System (ADS)

    Bai, Xiangzhi; Liu, Haonan

    2017-01-01

    Edge information is one of the critical information for infrared images. Morphological operators have been widely used for infrared image analysis. However, the edge information in infrared image is weak and the morphological operators could not well utilize the edge information of infrared images. To strengthen the edge information in morphological operators, the edge enhanced morphology is proposed in this paper. Firstly, the edge enhanced dilation and erosion operators are given and analyzed. Secondly, the pseudo operators which are derived from the edge enhanced dilation and erosion operators are defined. Finally, the applications for infrared image analysis are shown to verify the effectiveness of the proposed edge enhanced morphological operators. The proposed edge enhanced morphological operators are useful for the applications related to edge features, which could be extended to wide area of applications.

  16. The Zooniverse: Cutting Edge Scientific Research in the Classroom

    NASA Astrophysics Data System (ADS)

    Borden, K. A.; Whyte, L. F.; Smith, A.; Tarnoff, A.; Schmitt, H.

    2012-12-01

    Increasingly scientists and researchers from a multitude of disciplines are finding themselves inundated with more data than they could possibly interpret in a lifetime. Computers can be used entirely or partially for some data analysis; but there are some tasks that are currently best suited to human eyes, ears and brains. Zooniverse (www.zooniverse.org) invites members of the public to help researchers analyze and interpret data. To date, hundreds of thousands of volunteers have been involved in classifying images, interpreting sounds and transcribing texts. Zooniverse citizen scientists are providing valuable analyses across a variety of fields, from the hunt for exoplanets in Planet Hunters (planethunters.org) to the transcription of Greek papyri in Ancient Lives (ancientlives.org). Multiple academic publications have resulted from the combined efforts of the Zooniverse community and science teams demonstrating that citizen science is more than ever becoming a well-established method of doing research. Unlike most research projects the data, analysis and interactions with the science teams have an established and visible online presence through the project website and related discussion sites and blogs. These in themselves provide a valuable classroom resource, an opportunity for free and easy access to cutting edge scientific research. Anecdotal evidence exists that teacher can and already do use Zooniverse projects. By providing a rich and varied scaffolding to accompany the Zooniverse projects the opportunity exists for bringing citizen scientists to a wider classroom audience. An audience that may include non-specialist teachers, who require additional support to deliver challenging content, or time strapped educators who haven't the time to develop their own accompanying resources to weave Zooniverse projects into their lessons. During the session we will discuss the recent Zooniverse projects specifically designed to support and promote classroom adoption

  17. Fractal-based image edge detection

    NASA Astrophysics Data System (ADS)

    Luo, Huiguo; Zhu, Yaoting; Zhu, Guang-Xi; Wan, Faguang; Zhang, Ping

    1993-08-01

    Image edge is an important feature of image. Usually, we use Laplacian or Sober operator to get an image edge. In this paper, we use fractal method to get the edge. After introducing Fractal Brownian Random (FBR) field, we give the definition of Discrete Fractal Brownian Increase Random (DFBIR) field and discuss its properties, then we apply the DFBIR field to detect the edge of an image. According to the parameters H and D of DFBIR, we give a measure M equals (alpha) H + (beta) D. From the M value of each pixel, we can detect the edge of image.

  18. Edge-based correlation image registration for multispectral imaging

    DOEpatents

    Nandy, Prabal

    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.

  19. Cutting-edge issues of core-collapse supernova theory

    SciTech Connect

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    2014-05-02

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  20. Skype Me! Astronomers, Students, and Cutting-Edge Research

    NASA Astrophysics Data System (ADS)

    Hickox, Ryan C.; Gauthier, Adrienne J.

    2014-06-01

    A primary goal of many university science courses is to promote understanding of the process of contemporary scientific inquiry. One powerful way to achieve this is for students to explore current research and then interact directly with the leading scientist, the feasibility of which has recently increased dramatically due to free online video communication tools. We report on a program implemented at Dartmouth College in which students connect with a guest astronomer through Skype (video chat). The Skype session is wrapped in a larger activity where students explore current research articles, interact with the astronomer, and then reflect on the experience. The in-class Skype discussions require a small time commitment from scientists (20-30 minutes, with little or no need for preparation) while providing students direct access to researchers at the cutting edge of modern astronomy. We outline the procedures used to implement these discussions, and present qualitative assessments of student's understanding of the process of research, as well as feedback from the guest astronomers.

  1. Cutting-edge issues of core-collapse supernova theory

    NASA Astrophysics Data System (ADS)

    Kotake, Kei; Nakamura, Ko; Kuroda, Takami; Takiwaki, Tomoya

    2014-05-01

    Based on multi-dimensional neutrino-radiation hydrodynamic simulations, we report several cutting-edge issues about the long-veiled explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we pay particular attention to whether three-dimensional (3D) hydrodynamics and/or general relativity (GR) would or would not help the onset of explosions. By performing 3D simulations with spectral neutrino transport, we show that it is more difficult to obtain an explosion in 3D than in 2D. In addition, our results from the first generation of full general relativistic 3D simulations including approximate neutrino transport indicate that GR can foster the onset of neutrino-driven explosions. Based on our recent parametric studies using a light-bulb scheme, we discuss impacts of nuclear energy deposition behind the supernova shock and stellar rotation on the neutrino-driven mechanism, both of which have yet to be included in the self-consistent 3D supernova models. Finally we give an outlook with a summary of the most urgent tasks to extract the information about the explosion mechanisms from multi-messenger CCSN observables.

  2. Edge detection in microscopy images using curvelets

    PubMed Central

    Gebäck, Tobias; Koumoutsakos, Petros

    2009-01-01

    Background Despite significant progress in imaging technologies, the efficient detection of edges and elongated features in images of intracellular and multicellular structures acquired using light or electron microscopy is a challenging and time consuming task in many laboratories. Results We present a novel method, based on the discrete curvelet transform, to extract a directional field from the image that indicates the location and direction of the edges. This directional field is then processed using the non-maximal suppression and thresholding steps of the Canny algorithm to trace along the edges and mark them. Optionally, the edges may then be extended along the directions given by the curvelets to provide a more connected edge map. We compare our scheme to the Canny edge detector and an edge detector based on Gabor filters, and show that our scheme performs better in detecting larger, elongated structures possibly composed of several step or ridge edges. Conclusion The proposed curvelet based edge detection is a novel and competitive approach for imaging problems. We expect that the methodology and the accompanying software will facilitate and improve edge detection in images available using light or electron microscopy. PMID:19257905

  3. Edge plasmons and cut-off behavior of graphene nano-ribbon waveguides

    NASA Astrophysics Data System (ADS)

    Hou, Haowen; Teng, Jinghua; Palacios, Tomás; Chua, Soojin

    2016-07-01

    Graphene nano-ribbon waveguides with ultra-short plasmon wavelength are a promising candidate for nanoscale photonic applications. Graphene edge plasmons are the fundamental and lowest losses mode. Through finite element method, edge plasmons show large effective refractive index and strong field confinement on nanoscale ribbons. The edge plasmons follow a k1/2 dispersion relation. The wavelengths of the edge plasmons and center plasmons differ by a fixed factor. The width of edge plasmon is inversely proportional to wave vector of edge plasmon kedge. Edge defects associate with graphene nano-ribbon induce extra losses and reduce the propagation length. Cut-off width of edge plasmons reduces with increasing frequency. Cut-off width of center plasmon is enlarged by edge component but the enlargement effect diminishing with the increase of kedge. The results are important for the application of graphene plasmon towards ultra-compact photonic devices.

  4. Teaching Introductory Geoscience: A Cutting Edge Workshop Report

    NASA Astrophysics Data System (ADS)

    Manduca, C.; Tewksbury, B.; Egger, A.; MacDonald, H.; Kirk, K.

    2008-12-01

    Introductory undergraduate courses play a pivotal role in the geosciences. They serve as recruiting grounds for majors and future professionals, provide relevant experiences in geoscience for pre-service teachers, and offer opportunities to influence future policy makers, business people, professionals, and citizens. An introductory course is also typically the only course in geoscience that most of our students will ever take. Because the role of introductory courses is pivotal in geoscience education, a workshop on Teaching Introductory Courses in the 21st Century was held in July 2008 as part of the On the Cutting Edge faculty development program. A website was also developed in conjunction with the workshop. One of the central themes of the workshop was the importance of considering the long-term impact a course should have on students. Ideally, courses can be designed with this impact in mind. Approaches include using the local geology to focus the course and illustrate concepts; designing a course for particular audience (such as Geology for Engineers); creating course features that help students understand and interpret geoscience in the news; and developing capstone projects to teach critical thinking and problem solving skills in a geologic context. Workshop participants also explored strategies for designing engaging activities including exploring with Google Earth, using real-world scenarios, connecting with popular media, or making use of campus features on local field trips. In addition, introductory courses can emphasize broad skills such as teaching the process of science, using quantitative reasoning and developing communication skills. Materials from the workshop as well as descriptions of more than 150 introductory courses and 350 introductory-level activities are available on the website: http://serc.carleton.edu/NAGTWorkshops/intro/index.html.

  5. Study on edge extracting in noise image

    NASA Astrophysics Data System (ADS)

    Feng, Gui; Lin, Qiwei; Fu, QingQing

    2008-03-01

    In order to reduce the influence of noise on edge extracting and improve the precision of edge localization on the image, after analyzed the principle, strong points and short points of some traditional edge detecting methods, an effective algorithm for edge extracting in noise image was proposed in this paper. Adopting thought of traditional multi-directional and multistage combinational filtering, an image detail-preserving adaptive filter is designed to remove noise, and then extract the edge in the image. On the basis of the classical Sobel operator, we introduced an algorithm with resisting noise, good real-time and locating accurate edge. The algorithm can distinguish real edge from noise in terms of the theory of successive and smooth edge and random noise. The algorithm was accomplished under visual C++ 6.0 environment and tested by several standard images. The experimental result prove that the presented method is feasible and effective when the salt-pepper pollution of image is smaller than 15%, furthermore the method can extract edges with high location precision and good continuity accurately and effectively, at the same time, it has high processing speed.

  6. Active edge maps for medical image registration

    NASA Astrophysics Data System (ADS)

    Kerwin, William; Yuan, Chun

    2001-07-01

    Applying edge detection prior to performing image registration yields several advantages over raw intensity- based registration. Advantages include the ability to register multicontrast or multimodality images, immunity to intensity variations, and the potential for computationally efficient algorithms. In this work, a common framework for edge-based image registration is formulated as an adaptation of snakes used in boundary detection. Called active edge maps, the new formulation finds a one-to-one transformation T(x) that maps points in a source image to corresponding locations in a target image using an energy minimization approach. The energy consists of an image component that is small when edge features are well matched in the two images, and an internal term that restricts T(x) to allowable configurations. The active edge map formulation is illustrated here with a specific example developed for affine registration of carotid artery magnetic resonance images. In this example, edges are identified using a magnitude of gradient operator, image energy is determined using a Gaussian weighted distance function, and the internal energy includes separate, adjustable components that control volume preservation and rigidity.

  7. Image Edge Extraction via Fuzzy Reasoning

    NASA Technical Reports Server (NTRS)

    Dominquez, Jesus A. (Inventor); Klinko, Steve (Inventor)

    2008-01-01

    A computer-based technique for detecting edges in gray level digital images employs fuzzy reasoning to analyze whether each pixel in an image is likely on an edge. The image is analyzed on a pixel-by-pixel basis by analyzing gradient levels of pixels in a square window surrounding the pixel being analyzed. An edge path passing through the pixel having the greatest intensity gradient is used as input to a fuzzy membership function, which employs fuzzy singletons and inference rules to assigns a new gray level value to the pixel that is related to the pixel's edginess degree.

  8. An edge preserving differential image coding scheme

    NASA Technical Reports Server (NTRS)

    Rost, Martin C.; Sayood, Khalid

    1992-01-01

    Differential encoding techniques are fast and easy to implement. However, a major problem with the use of differential encoding for images is the rapid edge degradation encountered when using such systems. This makes differential encoding techniques of limited utility, especially when coding medical or scientific images, where edge preservation is of utmost importance. A simple, easy to implement differential image coding system with excellent edge preservation properties is presented. The coding system can be used over variable rate channels, which makes it especially attractive for use in the packet network environment.

  9. An edge preserving differential image coding scheme

    NASA Technical Reports Server (NTRS)

    Rost, Martin C.; Sayood, Khalid

    1991-01-01

    Differential encoding techniques are fast and easy to implement. However, a major problem with the use of differential encoding for images is the rapid edge degradation encountered when using such systems. This makes differential encoding techniques of limited utility especially when coding medical or scientific images, where edge preservation is of utmost importance. We present a simple, easy to implement differential image coding system with excellent edge preservation properties. The coding system can be used over variable rate channels which makes it especially attractive for use in the packet network environment.

  10. Diffusivity in multiple sclerosis lesions: At the cutting edge?

    PubMed

    Klistorner, Alexander; Wang, Chenyu; Fofanova, Vera; Barnett, Michael H; Yiannikas, Con; Parratt, John; You, Yuyi; Graham, Stuart L

    2016-01-01

    Radial Diffusivity (RD) has been suggested as a promising biomarker associated with the level of myelination in MS lesions. However, the level of RD within the lesion is affected not only by loss of myelin sheaths, but also by the degree of tissue destruction. This may lead to exaggeration of diffusivity measures, potentially masking the effect of remyelination. To test the hypothesis that the T2 hyperintense lesion edge that extends beyond the T1 hypointense lesion core is less affected by tissue loss, and therefore a more appropriate target for imaging biomarker development targeting de- and re-myelination. Pre- and post-gadolinium (Gd) enhanced T1, T2 and DTI images were acquired from 75 consecutive RRMS patients. The optic radiation (OR) was identified in individual patients using a template-based method. T2 lesions were segmented into T1-hypointense and T1-isointense areas and lesion masks intersected with the OR. Average Radial, Axial and Mean diffusivity (RD, AD and MD) and fractional anisotropy (FA) were calculated for lesions of the entire brain and the OR. In addition, Gd enhancing lesions were excluded from the analysis. 86% of chronic T2 lesions demonstrated hypointense areas on T1-weighted images, which typically occupied the central part of each T2 lesion, taking about 40% of lesional volume. The T1-isointense component of the T2 lesion was most commonly seen as a peripheral ring of relatively constant thickness ("T2-rim"). While changes of diffusivity between adjacent normal appearing white matter and the "T2-rim" demonstrated a disproportionally high elevation of RD compare to AD, the increase of water diffusion was largely isointense between the "T2-rim" and T1-hypointense parts of the lesion. Distinct patterns of diffusivity within the central and peripheral components of MS lesions suggest that axonal loss dominates in the T1 hypointense core. The effects of de/remyelination may be more readily detected in the "T2-rim", where there is relative

  11. Deep cutting injury from the edges of a snowboard.

    PubMed

    Matsunaga, T; Saitoh, S; Tanikawa, H; Hayashi, M; Ohira, M; Kimura, T

    2004-02-01

    A laceration deep enough to reach the bone occurs very rarely in skiing or snowboarding. Two such cases are presented here. In one case, the popliteal fossa of a skier was cut during a collision with a snowboarder. All structures posterior to the knee were severed and the leg became ischaemic. The other case was of a snowboarder who sustained a deep cut to the distal forearm during landing after a jump, resulting in a "spaghetti wrist".

  12. Cutting edge technology to enhance nursing classroom instruction at Coppin State University.

    PubMed

    Black, Crystal Day; Watties-Daniels, A Denyce

    2006-01-01

    Educational technologies have changed the paradigm of the teacher-student relationship in nursing education. Nursing students expect to use and to learn from cutting edge technology during their academic careers. Varied technology, from specified software programs (Tegrity and Blackboard) to the use of the Internet as a research medium, can enhance student learning. The authors provide an overview of current cutting edge technologies in nursing classroom instruction and its impact on future nursing practice.

  13. New applications of Spectral Edge image fusion

    NASA Astrophysics Data System (ADS)

    Hayes, Alex E.; Montagna, Roberto; Finlayson, Graham D.

    2016-05-01

    In this paper, we present new applications of the Spectral Edge image fusion method. The Spectral Edge image fusion algorithm creates a result which combines details from any number of multispectral input images with natural color information from a visible spectrum image. Spectral Edge image fusion is a derivative-based technique, which creates an output fused image with gradients which are an ideal combination of those of the multispectral input images and the input visible color image. This produces both maximum detail and natural colors. We present two new applications of Spectral Edge image fusion. Firstly, we fuse RGB-NIR information from a sensor with a modified Bayer pattern, which captures visible and near-infrared image information on a single CCD. We also present an example of RGB-thermal image fusion, using a thermal camera attached to a smartphone, which captures both visible and low-resolution thermal images. These new results may be useful for computational photography and surveillance applications.

  14. [The morphological characteristic of the skin lesions inflicted by plastic knives with four cutting edges].

    PubMed

    Leonov, S V; Finkel'shtein, V T

    2015-01-01

    The objective of the present work was to study the morphological features of the skin lesions inflicted by the blades of the Fgx Boot Blade I knives having four cutting edges. The study revealed the signs that can be used to distinguish between morphological characteristics of the stab and lacerated wounds having the primary and secondary incisions made by the four-edge blade.

  15. Influence of edging practices on cutting yields of Alaska birch lumber

    Treesearch

    David L. Nicholls; J.W. Funck; C.C. Brunner; J.E. Reeb

    2009-01-01

    Birch lumber is often characterized by a high degree of knots, bark pockets, heartwood, and other features which force sawmill owners to decide whether to edge and trim boards to produce standard grade lumber vs. proprietary grade character-marked lumber. In addition, the edging strategies used with irregularly shaped flitches can greatly influence cut-stock recovery....

  16. NiTinol-based cutting edges for endovascular heart valve resection: first in-vitro cutting results.

    PubMed

    Wendt, Daniel; Stühle, Sebastian; Kawa, Emilia; Thielmann, Matthias; Kipfmüller, Brigitte; Wendt, Hermann; Hauck, Florian; Vogel, Bernd; Fischer, Harald; Jakob, Heinz

    2009-01-01

    Machining of shape memory alloys based on Nitinol (NiTi) creates difficulties due to its ductility and severe strain hardening. In this experiment, different cutting edges and grinding parameters were tested to optimize cutting results on NiTi-based blades intended for endovascular heart valve resection. The cutting procedure was performed using two counter-rotating circular NiTi blades of different diameter. A rotating/punching process should be performed. Different shapes (glazed, waved, and saw tooth), different grinding techniques (manual, manual grinder, and precise milling cutter) and additionally various velocities (50 and 200 rpm) were tested on specific test specimens. Cutting forces were measured and cutting quality was examined using digital microscopy. Preliminary tests with rotating blades showed superior results using cutting edges for the punching process (150 N vs. 200 N; n=7). In a second step special test specimens were tested. Maximum cutting-force was 265 N+/-20 N (mean+/-SD; n=7). Subsequently different shapes were tested at 50 and 200 rpm using the rotating/punching method regarding alternate grinding techniques. Cutting forces were 27 N+/-7.7 N for glazed blades (n=7) at 50 rpm and 18 N+/-4.7 N at 200 rpm, waved blades (n=7) required a maximum force of 18 N+/-5 N at 50 rpm and 11 N+/-3.3 N at 200 rpm, whereas saw tooth blades (n=7) needed 17 N+/-12.7 N at 50 rpm and 9 N+/-1.2 N at 200 rpm. Precise cutting quality was only seen when using glazed blades sharpened under accurate conditions with a high-speed milling cutter. Although shape memory alloys based on Nitinol are difficult to process, and well-defined grinding parameters do not exist, acceptable results can be reached using high-speed milling cutters. Best cutting quality can be observed by using glazed blades, performing a rotating/punching process at high velocities. Lower cutting forces can be observed by using other shape-types, however this leads to lower cutting quality. Therefore

  17. Coherent structures shed by multiscale cut-in trailing edge serrations on lifting wings

    NASA Astrophysics Data System (ADS)

    Prigent, S. L.; Buxton, O. R. H.; Bruce, P. J. K.

    2017-07-01

    This experimental study presents the effect of multiscale cut-in trailing edge serrations on the coherent structures shed into the wake of a lifting wing. Two-probe span-wise hot-wire traverses are performed to study spectra, coherence, and phase shift. In addition, planar particle image velocimetry is used to study the spatio-temporal structure of the vortices shed by the airfoils. Compared with a single tone sinusoidal serration, the multiscale ones reduce the vortex shedding energy as well as the span-wise coherence. Results indicate that the vortex shedding is locked into an arch-shaped cell structure. This structure is weakened by the multiscale patterns, which explains the reduction in both shedding energy and coherence.

  18. Comparative Study of Edge Detectors in case of Echocardiographic Images

    NASA Astrophysics Data System (ADS)

    Saini, Kalpana; Dewal, M. L.; Rohit, Manoj Kumar

    2010-11-01

    In this paper we compare different edge detectors based on peak signal to noise ratio on Echocardiographic images. Edge detection is a critical element in image processing, since edges contain a major function of image information. The function of edge detection is to identify the boundaries of homogeneous regions in an image based on properties such as intensity and texture.We have taken Perwitt edge detector, Robarts edge detector, LoG edge detector, Canny edge detector, and Sobel edge detector for this comparison and study.

  19. Investigation on the Bearing Abilities of Three-Dimensional Full Five-Directional Braided Composites with Cut-Edge

    NASA Astrophysics Data System (ADS)

    Wang, Yibo; Liu, Zhenguo; Lei, Bing; Huang, Xiang; Li, Xiaokang

    2017-08-01

    The longitudinal tensile experiments of cut-edge effect on the mechanical performance of three-dimensional full five-directional (3DF5D) braided composites were conducted. The specimens involved two different braiding angles and two different cutting ways. Fracture appearance of specimens without cut-edge and cutting along width direction presented flush, while explosive for specimen with cut-edge along thickness direction. The fracture of axis yarns mainly contributed to the damage of specimens. Cut-edge had little influence on the stiffness of 3DF5D braided composites and had approximately 20 % reduction in tensile strength compared with specimens without cut-edge. The periodic boundary conditions under cut-edge and uncut-edge situations were applied to the RVC to simulate the mesoscopic damage mechanism using finite element method. The stress-strain curves and damage evolution nephogram were obtained. The variation of cut-edge effect with the number of inner cells was predicted by superimposing inner cells method, the addition of inner cells could strengthen the performance of 3DF5D braided composites with cut-edge. These results will play an important role in evaluating the mechanical properties of braided materials after cutting.

  20. Investigation on the Bearing Abilities of Three-Dimensional Full Five-Directional Braided Composites with Cut-Edge

    NASA Astrophysics Data System (ADS)

    Wang, Yibo; Liu, Zhenguo; Lei, Bing; Huang, Xiang; Li, Xiaokang

    2016-11-01

    The longitudinal tensile experiments of cut-edge effect on the mechanical performance of three-dimensional full five-directional (3DF5D) braided composites were conducted. The specimens involved two different braiding angles and two different cutting ways. Fracture appearance of specimens without cut-edge and cutting along width direction presented flush, while explosive for specimen with cut-edge along thickness direction. The fracture of axis yarns mainly contributed to the damage of specimens. Cut-edge had little influence on the stiffness of 3DF5D braided composites and had approximately 20 % reduction in tensile strength compared with specimens without cut-edge. The periodic boundary conditions under cut-edge and uncut-edge situations were applied to the RVC to simulate the mesoscopic damage mechanism using finite element method. The stress-strain curves and damage evolution nephogram were obtained. The variation of cut-edge effect with the number of inner cells was predicted by superimposing inner cells method, the addition of inner cells could strengthen the performance of 3DF5D braided composites with cut-edge. These results will play an important role in evaluating the mechanical properties of braided materials after cutting.

  1. A cutting-edge solution for 1µm laser metal processing

    NASA Astrophysics Data System (ADS)

    Baumbach, N.; Kühl, P.; Karam, J.; Jonkers, J.; Villarreal-Saucedo, F.; Reyes, M.

    2017-02-01

    The recent 1μm-laser cutting market is dominated by fiber and disk lasers due to their excellent beam quality of below 4mm*mrad. Teradiode's 4kW direct diode laser source achieves similar beam quality while having a different beam shape and shorter wavelengths which are known for higher absorption rates at the inclined front of the cutting keyhole. Research projects, such as the HALO Project, have additionally shown that polarized radiation and beams with shapes different from the typical LG00 lead to improved cut quality for ferrous and non-ferrous metals. [1] Diode laser have the inherent property of not being sensitive to back reflection which brings advantages in cutting high-reflective materials. The II-VI HIGHYAG laser cutting head BIMO-FSC offers the unique feature of machine controlled and continuous adjustment of both the focus diameter and the focus position. This feature is proven to be beneficial for cutting and piercing with high speed and small hole diameters. In addition, the optics are designed for lowest focus shift. As a leading laser processing head manufacturer, II-VI HIGHYAG qualified its BIMO-FSC MZ (M=magnification, Z=focus position) cutting head for Teradiode's 4kW direct diode laser source to offer a cutting-edge solution for highpower laser cutting. Combining the magnification ability of the cutting head with this laser source, customers experience strong advantages in cutting metals in broad thickness ranges. Thicknesses up to 25mm mild steel can easily be cut with excellent edge quality. Furthermore, a new optical setup equivalent to an axicon with a variable axicon angle is demonstrated which generates variable sized ring spots. The setup provides new degrees of freedom to tailor the energy distribution for even higher productivity and quality.

  2. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

    1996-03-19

    A method is described for welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads. 7 figs.

  3. Simultaneous laser cutting and welding of metal foil to edge of a plate

    DOEpatents

    Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

    1996-01-01

    A method of welding an ultra-thin foil to the edge of a thicker sheet to form a vacuum insulation panel comprising the steps of providing an ultra-thin foil having a thickness less than 0.002, providing a top plate having an edge and a bottom plate having an edge, clamping the foil to the edge of the plate wherein the clamps act as heat sinks to distribute heat through the foil, providing a laser, moving the laser relative to the foil and the plate edges to form overlapping weld beads to weld the foil to the plate edges while simultaneously cutting the foil along the weld line formed by the overlapping beads.

  4. Impact of the On the Cutting Edge Professional Development Program on U.S. Geoscience Faculty

    NASA Astrophysics Data System (ADS)

    Manduca, C. A.; Iverson, E. A.; Czujko, R.; Macdonald, H.; Mogk, D. W.; Tewksbury, B. J.; McLaughlin, J.; Sanford, C.; Greenseid, L.; Luxenberg, M.

    2011-12-01

    Transforming STEM education from a dominantly lecture-based format focused on facts to classrooms where students engage with the process of understanding the world through science is a primary goal of faculty development. On the Cutting Edge seeks to support this transformation by using workshops and a website to build a community of geoscience faculty who learn from one another. In order to assess the impact of the On the Cutting Edge program, we surveyed 5917 U.S. geoscience faculty in 2009 and received 2874 completed responses (49% response rate). We looked at the differences in responses between workshop participants who also use the website, website users who have not attended a Cutting Edge workshop, and survey respondents who had neither attended a Cutting Edge workshop nor used the Cutting Edge website. The number of respondents who had attended a Cutting Edge workshop and had not used the website was too small to analyze. Courses described by Cutting Edge workshop participants make significantly less use of lecture and more use of small group discussion and in-class activities. While all faculty respondents routinely update their courses, workshop participants are more likely to have changed their teaching methods in the two years leading up to the survey. When making changes to their teaching methods, workshop participants are more likely than other populations to seek information about teaching on the web, consult journal articles about teaching, and seek advice from colleagues outside their department and from nationally known leaders in geoscience education. Workshop participants are also more likely to tell a colleague when they do something that is particularly successful in class. End-of-workshop survey and follow-up interview data indicate that participants leave workshops reinvigorated, with a new or renewed commitment to student-centered teaching, and that they make use of the website as they implement ideas for changing their teaching following

  5. STRUCTURAL ANNOTATION OF EM IMAGES BY GRAPH CUT

    SciTech Connect

    Chang, Hang; Auer, Manfred; Parvin, Bahram

    2009-05-08

    Biological images have the potential to reveal complex signatures that may not be amenable to morphological modeling in terms of shape, location, texture, and color. An effective analytical method is to characterize the composition of a specimen based on user-defined patterns of texture and contrast formation. However, such a simple requirement demands an improved model for stability and robustness. Here, an interactive computational model is introduced for learning patterns of interest by example. The learned patterns bound an active contour model in which the traditional gradient descent optimization is replaced by the more efficient optimization of the graph cut methods. First, the energy function is defined according to the curve evolution. Next, a graph is constructed with weighted edges on the energy function and is optimized with the graph cut algorithm. As a result, the method combines the advantages of the level set method and graph cut algorithm, i.e.,"topological" invariance and computational efficiency. The technique is extended to the multi-phase segmentation problem; the method is validated on synthetic images and then applied to specimens imaged by transmission electron microscopy(TEM).

  6. Remote laser cutting of CFRP: influence of the edge quality on fatigue strength

    NASA Astrophysics Data System (ADS)

    Stock, Johannes W.; Zaeh, Michael F.; Spaeth, Justinian P.

    2014-02-01

    The additional weight of the batteries in electric cars can be compensated by using carbon fiber reinforced plastics (CFRP) for structural parts of the passenger cell. Various machining processes for CFRP are currently subject to investigations. Milling and abrasive waterjet cutting implicate fiber pull out or delamination and, thus, do not thoroughly meet the requirements for mass production. Despite this, laser beam cutting has a great potential in large scale cutting of CFRP and is a predominant research topic. Remote laser beam cutting especially provides a good cut surface quality. Currently, the correlation between cutting parameters and edge quality is not sufficiently known. In particular, studies on the dynamic strength of remote laser cut parts are missing. Therefore, fatigue testing was performed with specimens cut by laser radiation and the results were compared with others made by milling and abrasive waterjet cutting. With these experiments, a comparable study of the different methods of CFRP cutting was achieved. The influence of both the heat affected zone (HAZ) and of defects like micro-fissures on the fatigue strength were evaluated.

  7. Faculty as Filmmakers: On the Cutting Edge of Classroom Technologies

    ERIC Educational Resources Information Center

    Rozensher, Susan G.

    2007-01-01

    Digital video equipment and studios newly available for faculty use can be incorporated into the technological repertoire of college faculty, enabling professors to customize and enhance the learning experience of their students. Today's students are particularly attuned to analyzing visual images and data, so the use of customized films in the…

  8. The Cutting Edge: Satellite Chamber, Lasers Spur LC Preservation Effort.

    ERIC Educational Resources Information Center

    Brandehoff, Susan E.

    1982-01-01

    Describes efforts to preserve important library materials at the Library of Congress through the use of two new technologies: a patented deacidification process in which books are placed in a vacuum chamber, and the use of optical disc recording techniques to miniaturize and store print and nonprint images. (JL)

  9. Faculty as Filmmakers: On the Cutting Edge of Classroom Technologies

    ERIC Educational Resources Information Center

    Rozensher, Susan G.

    2007-01-01

    Digital video equipment and studios newly available for faculty use can be incorporated into the technological repertoire of college faculty, enabling professors to customize and enhance the learning experience of their students. Today's students are particularly attuned to analyzing visual images and data, so the use of customized films in the…

  10. Lithographic imaging-driven pattern edge placement errors at the 10-nm node

    NASA Astrophysics Data System (ADS)

    Tyminski, Jacek K.; Sakamoto, Julia A.; Palmer, Shane R.; Renwick, Stephen P.

    2016-04-01

    As new microelectronic designs are being developed, the demands on image overlay and pattern dimension control are compounded by requirements that pattern edge placement errors (EPEs) be at a single-nanometer levels. Scanner performance plays a key role in determining location of the pattern edges at different device layers, not only through overlay but also through imaging performance. The imaging contributes to edge displacement through the variations of the image dimensions and by shifting the images from their target locations. We discuss various aspects of advanced image control relevant to a 10-nm node integrated circuit design. We review a range of issues of pattern edge placement directly linked to pattern imaging. We analyze the impact of different pattern design and scanner-related edge displacement drivers. We present two examples of imaging strategies to pattern logic device metal layer cuts. We analyze EPEs of the cut images resulting from optimized layout design and scanner setup, and we draw conclusions on edge placement control versus imaging performance requirements.

  11. Pupillometry: Cutting Edge Biometrics for Early Intervention in Increased Intracranial Pressure.

    PubMed

    John, Jennilee St

    2015-10-01

    The pupillometer, a cutting-edge biometric device, is a valuable assessment tool that can aid in the early detection and prompt treatment of neurological abnormalities. Pupil assessment is a critical component of the neurological examination, and manual pupil assessment leaves much room for error. Automated pupillometry improves the quality and reliability of pupillary and neurological assessments, ultimately improving patient outcomes.

  12. The Snowmastodon Project: cutting-edge science on the blade of a bulldozer

    USGS Publications Warehouse

    Pigati, Jeffery S.; Miller, Ian M.; Johnson, Kirk R.

    2015-01-01

    Cutting-edge science happens at a variety of scales, from the individual and intimate to the large-scale and collaborative. The publication of a special issue of Quaternary Research in Nov. 2014 dedicated to the scientific findings of the “Snowmastodon Project” highlights what can be done when natural history museums, governmental agencies, and academic institutions work toward a common goal.

  13. Cutting-Edge Technologies and Social Media Use in Higher Education

    ERIC Educational Resources Information Center

    Benson, Vladlena, Ed.; Morgan, Stephanie

    2014-01-01

    The inclusion of social media in higher education has transformed the way instructors teach and students learn. In order to effectively reach their students in this networked world, teachers must learn to utilize the latest technologies in their classrooms. "Cutting-Edge Technologies and Social Media Use in Higher Education" brings…

  14. Cutting-Edge Technologies and Social Media Use in Higher Education

    ERIC Educational Resources Information Center

    Benson, Vladlena, Ed.; Morgan, Stephanie

    2014-01-01

    The inclusion of social media in higher education has transformed the way instructors teach and students learn. In order to effectively reach their students in this networked world, teachers must learn to utilize the latest technologies in their classrooms. "Cutting-Edge Technologies and Social Media Use in Higher Education" brings…

  15. Building Institutional Capacity for Data-Informed Decision Making. Cutting Edge Series. No. 3

    ERIC Educational Resources Information Center

    Public Agenda, 2012

    2012-01-01

    "Building Institutional Capacity for Data-Informed Decision Making" is the third installment of the Cutting Edge series, which aims to help colleges engage faculty, scale successful interventions, and create a strong culture of evidence through use of data to strengthen their institutional change and student success efforts. Though the…

  16. Tapping Recent Alumni for the Development of Cutting-Edge, Investigative Teaching Laboratory Experiments

    ERIC Educational Resources Information Center

    Brodl, Mark R.

    2005-01-01

    This project presents a model for the development of an innovative, highly-experimental teaching laboratory course that centers upon collaborative efforts between recent alumni currently enrolled in Ph. D. programs (consultants) and current faculty. Because these consultants are involved in cutting-edge research, their combined talents represent a…

  17. What's Your Story?: Dutch Library DOK's New Cutting-Edge Community Tech Projects

    ERIC Educational Resources Information Center

    Boekesteijn, Erik

    2010-01-01

    DOK, the cutting-edge library center in Delft, the Netherlands, has been finding new ways to elaborate on the social networking impulse. A good library unites people from all levels of society, and DOK's unique innovation department focuses specifically on how media can bring people together. It's doing so using technology to inspire and connect…

  18. Kinect, a Novel Cutting Edge Tool in Pavement Data Collection

    NASA Astrophysics Data System (ADS)

    Mahmoudzadeh, A.; Firoozi Yeganeh, S.; Golroo, A.

    2015-12-01

    Pavement roughness and surface distress detection is of interest of decision makers due to vehicle safety, user satisfaction, and cost saving. Data collection, as a core of pavement management systems, is required for these detections. There are two major types of data collection: traditional/manual data collection and automated/semi-automated data collection. This paper study different non-destructive tools in detecting cracks and potholes. For this purpose, automated data collection tools, which have been utilized recently are discussed and their applications are criticized. The main issue is the significant amount of money as a capital investment needed to buy the vehicle. The main scope of this paper is to study the approach and related tools that not only are cost-effective but also precise and accurate. The new sensor called Kinect has all of these specifications. It can capture both RGB images and depth which are of significant use in measuring cracks and potholes. This sensor is able to take image of surfaces with adequate resolution to detect cracks along with measurement of distance between sensor and obstacles in front of it which results in depth of defects. This technology has been very recently studied by few researchers in different fields of studies such as project management, biomedical engineering, etc. Pavement management has not paid enough attention to use of Kinect in monitoring and detecting distresses. This paper is aimed at providing a thorough literature review on usage of Kinect in pavement management and finally proposing the best approach which is cost-effective and precise.

  19. Bearing Abilities and Progressive Damage Analysis of Three Dimensional Four-Directional Braided Composites with Cut-Edge

    NASA Astrophysics Data System (ADS)

    Lei, Bing; Liu, Zhenguo; Ya, Jixuan; Wang, Yibo; Li, Xiaokang

    2016-08-01

    Cut-edge is a kind of damage for the three-dimensional four-directional (3D4d) braided composites which is inevitable because of machining to meet requisite shape and working in the abominable environment. The longitudinal tensile experiment of the 3D4d braided composites with different braiding angles between cut-edge and the ones without cut-edge was conducted. Then representative volume cell (RVC) with interface zones was established to analyze the tensile properties through the fracture and damage mechanics. The periodic boundary conditions under the cut-edge and uncut-edge conditions were imposed to simulate the failure mechanism. Stress-strain distribution and the damage evolution nephogram in cut-edge condition were conducted. Numerical results were coincident with the experimental results. Finally the variation of cut-edge effect with the specimen thickness was simulated by superimposing inner cells. The consequence showed that thickness increase can effectively reduce cut-edge influence on longitudinal strength for 3D4d braided composites. Cut-edge simulation of braided composites has guiding significance on the actual engineering application.

  20. Edge-induced narrowing of dietary diversity in leaf-cutting ants.

    PubMed

    Falcão, P F; Pinto, S R R; Wirth, R; Leal, I R

    2011-06-01

    Much of the ecological alteration faced by human-modified Neotropical forests can be assigned to edge effects, including the proliferation of some voracious herbivores such as leaf-cutting ants. However, the underlying mechanisms/impacts of tropical forest edge on herbivores performance and their foraging behaviour (e.g. dietary diversity) have rarely been investigated. The goal of this study was, therefore, to determine whether and how the annual diet (i.e. species richness, diversity and the relative proportion of pioneer versus non-pioneer species of plant materials) of Atta cephalotes colonies differs in the forest edge versus the interior zone of a large remnant of Atlantic forest in northeastern Brazil. Among the key results was a strong habitat effect on dietary diversity (explaining ca. 40-50% of the variation), which, in edge colonies, decreased approximately by one fourth compared to interior colonies (inverse of Simpson's index: 3.7±0.84 versus 4.99±0.95). There was a predominance of leaf fragments collected from pioneer species in the diet in both habitat (86% in edge and 80.4% in interior). Edge colonies collected proportionally more fragments from pioneer species than colonies located in the forest interior. Our results are the first to demonstrate an edge-mediated relaxation of dietary restrictions in leaf-cutting ants. These findings render robust support to previous evidence indicating the reduction of bottom-up forces as a key factor explaining both edge-induced hyper-abundance and increased herbivory of leaf-cutting ants in human-modified Neotropical landscapes.

  1. Canny edge-based deformable image registration

    NASA Astrophysics Data System (ADS)

    Kearney, Vasant; Huang, Yihui; Mao, Weihua; Yuan, Baohong; Tang, Liping

    2017-02-01

    This work focuses on developing a 2D Canny edge-based deformable image registration (Canny DIR) algorithm to register in vivo white light images taken at various time points. This method uses a sparse interpolation deformation algorithm to sparsely register regions of the image with strong edge information. A stability criterion is enforced which removes regions of edges that do not deform in a smooth uniform manner. Using a synthetic mouse surface ground truth model, the accuracy of the Canny DIR algorithm was evaluated under axial rotation in the presence of deformation. The accuracy was also tested using fluorescent dye injections, which were then used for gamma analysis to establish a second ground truth. The results indicate that the Canny DIR algorithm performs better than rigid registration, intensity corrected Demons, and distinctive features for all evaluation matrices and ground truth scenarios. In conclusion Canny DIR performs well in the presence of the unique lighting and shading variations associated with white-light-based image registration.

  2. Cutting edge clinical applications in cardiovascular magnetic resonance.

    PubMed

    De Cecco, Carlo N; Muscogiuri, Giuseppe; Varga-Szemes, Akos; Schoepf, U Joseph

    2017-01-28

    Today, the use of cardiovascular magnetic resonance (CMR) is widespread in clinical practice. The increased need to evaluate of subtle myocardial changes, coronary artery anatomy, and hemodynamic assessment has prompted the development of novel CMR techniques including T1 and T2 mapping, non-contrast angiography and four dimensional (4D) flow. T1 mapping is suitable for diagnosing pathologies affecting extracellular volume such as myocarditis, diffuse myocardial fibrosis and amyloidosis, and is a promising diagnostic tool for patients with iron overload and Fabry disease. T2 mapping is useful in depicting acute myocardial edema and estimating the amount of salvageable myocardium following an ischemic event. Novel angiography techniques, such as the self-navigated whole-heart or the quiescent-interval single-shot sequence, enable the visualization of the great vessels and coronary artery anatomy without the use of contrast material. The 4D flow technique overcomes the limitations of standard phase-contrast imaging and allows for the assessment of cardiovascular hemodynamics in the great arteries and flow patterns in the cardiac chambers. In conclusion, the future of CMR is heading toward a more reliable quantitative assessment of the myocardium, an improved non-contrast visualization of the coronary artery anatomy, and a more accurate evaluation of the cardiac hemodynamics.

  3. Cutting edge clinical applications in cardiovascular magnetic resonance

    PubMed Central

    De Cecco, Carlo N; Muscogiuri, Giuseppe; Varga-Szemes, Akos; Schoepf, U Joseph

    2017-01-01

    Today, the use of cardiovascular magnetic resonance (CMR) is widespread in clinical practice. The increased need to evaluate of subtle myocardial changes, coronary artery anatomy, and hemodynamic assessment has prompted the development of novel CMR techniques including T1 and T2 mapping, non-contrast angiography and four dimensional (4D) flow. T1 mapping is suitable for diagnosing pathologies affecting extracellular volume such as myocarditis, diffuse myocardial fibrosis and amyloidosis, and is a promising diagnostic tool for patients with iron overload and Fabry disease. T2 mapping is useful in depicting acute myocardial edema and estimating the amount of salvageable myocardium following an ischemic event. Novel angiography techniques, such as the self-navigated whole-heart or the quiescent-interval single-shot sequence, enable the visualization of the great vessels and coronary artery anatomy without the use of contrast material. The 4D flow technique overcomes the limitations of standard phase-contrast imaging and allows for the assessment of cardiovascular hemodynamics in the great arteries and flow patterns in the cardiac chambers. In conclusion, the future of CMR is heading toward a more reliable quantitative assessment of the myocardium, an improved non-contrast visualization of the coronary artery anatomy, and a more accurate evaluation of the cardiac hemodynamics. PMID:28144400

  4. Cutting-Edge: Integrating Students with Intellectual and Developmental Disabilities into a 4-Year Liberal Arts College

    ERIC Educational Resources Information Center

    Hafner, Dedra; Moffatt, Courtney; Kisa, Nutullah

    2011-01-01

    Cutting-Edge provides inclusion in college for students with intellectual disabilities (SWID). Cutting-Edge students attended college by taking undergraduate courses, resided in student housing, and engaged in student-life events as well as pursued community service, internships and employment. Undergraduate students were the best means to teach…

  5. Cutting-Edge: Integrating Students with Intellectual and Developmental Disabilities into a 4-Year Liberal Arts College

    ERIC Educational Resources Information Center

    Hafner, Dedra; Moffatt, Courtney; Kisa, Nutullah

    2011-01-01

    Cutting-Edge provides inclusion in college for students with intellectual disabilities (SWID). Cutting-Edge students attended college by taking undergraduate courses, resided in student housing, and engaged in student-life events as well as pursued community service, internships and employment. Undergraduate students were the best means to teach…

  6. Cleaning capacity of hybrid instrumentation technique using reamer with alternating cutting edges system files: Histological analysis.

    PubMed

    Júnior, Emilio Carlos Sponchiado; da Fonseca, Tiago Silva; da Frota, Matheus Franco; de Carvalho, Fredson Marcio Acris; Marques, André Augusto Franco; Garcia, Lucas da Fonseca Roberti

    2014-04-01

    The aim of the following study is to evaluate the cleaning capacity of a hybrid instrumentation technique using Reamer with Alternating Cutting Edges (RaCe) system files in the apical third of mesial roots of mandibular molars. Twenty teeth were selected and separated into two groups (n = 20) according to instrumentation technique as follows: BioRaCe - chemomechanical preparation with K-type files #10 and #15; and files BioRaCe BR0, BR1, BR2, BR3, and BR4; HybTec - hybrid instrumentation technique with K-type files #10 and #15 in the working length, #20 at 2 mm, #25 at 3 mm, cervical preparation with Largo burs #1 and #2; apical preparation with K-type files #15, #20, and #25 and RaCe files #25.04 and #30.04. The root canals were irrigated with 1 ml of 2.5% sodium hypochlorite at each change of instrument. The specimens were histologically processed and photographed under light optical microscope. The images were inserted onto an integration grid to count the amount of debris present in the root canal. BioRaCe presented the highest percentage of debris in the apical third, however, with no statistically significant difference for HybTec (P > 0.05). The hybrid technique presented similar cleaning capacity as the technique recommended by the manufacturer.

  7. Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates.

    PubMed

    Muller, Antoine; Clarkson, Chris

    2016-01-01

    The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency.

  8. Identifying Major Transitions in the Evolution of Lithic Cutting Edge Production Rates

    PubMed Central

    Clarkson, Chris

    2016-01-01

    The notion that the evolution of core reduction strategies involved increasing efficiency in cutting edge production is prevalent in narratives of hominin technological evolution. Yet a number of studies comparing two different knapping technologies have found no significant differences in edge production. Using digital analysis methods we present an investigation of raw material efficiency in eight core technologies broadly representative of the long-term evolution of lithic technology. These are bipolar, multiplatform, discoidal, biface, Levallois, prismatic blade, punch blade and pressure blade production. Raw material efficiency is assessed by the ratio of cutting edge length to original core mass. We also examine which flake attributes contribute to maximising raw material efficiency, as well as compare the difference between expert and intermediate knappers in terms of cutting edge produced per gram of core. We identify a gradual increase in raw material efficiency over the broad sweep of lithic technological evolution. The results indicate that the most significant transition in efficiency likely took place with the introduction of small foliate biface, Levallois and prismatic blade knapping, all introduced in the Middle Stone Age / Middle Palaeolithic among early Homo sapiens and Neanderthals. This suggests that no difference in raw material efficiency existed between these species. With prismatic blade technology securely dated to the Middle Palaeolithic, by including the more recent punch and pressure blade technology our results dispel the notion that the transition to the Upper Palaeolithic was accompanied by an increase in efficiency. However, further increases in cutting edge efficiency are evident, with pressure blades possessing the highest efficiency in this study, indicating that late/epi-Palaeolithic and Neolithic blade technologies further increased efficiency. PMID:27936135

  9. A novel algorithm for the edge detection and edge enhancement of medical images.

    PubMed

    Crooks, I; Fallone, B G

    1993-01-01

    A novel algorithm, histogram shifting (HS) is presented, which performs edge detection or edge enhancement with the choice of two parameters. The histogram of a region surrounding each pixel is found and translated toward the origin, resulting in the new pixel value. Images from a variety of medical imaging modalities were processed with HS to perform detection and enhancement of edges. Comparison with results obtained from conventional edge detection (e.g., Sobel) and with conventional edge-enhancement algorithms is discussed. HS appears to perform the edge-detection operation without introducing "double-edge" effects often obtained with conventional edge-detection algorithms. HS also appears to perform edge enhancement without introducing extensive noise artifacts, which may be noticeable with many edge-enhancement algorithms.

  10. Liquid-Crystal Light Valve Enhances Edges In Images

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Liu, Hua-Kuang

    1991-01-01

    Experiments show liquid-crystal light valve (LCLV) exhibits operating mode in which it enhances edges in images projected on it. Operates in edge-enhancing mode (or in combination of edge-enhancing and normal modes) by suitably adjusting bias voltage and frequency. Enhancement of edges one of most important preprocessing steps in optical pattern-recognition systems. Incorporated into image-processing system to enhance edges without introducing excessive optical noise.

  11. Computing of the Theoretical Value of Roughness Parameter Rz when Turning with Helical Cutting Edge

    NASA Astrophysics Data System (ADS)

    Šajgalík, Michal; Martikáň, Anton; Czán, Andrej; Pile, Jozef; Holubják, Jozef; Mrázik, Jozef

    2016-12-01

    This article describes process of computing and identifying of the value of roughness parameter Rz deduced from basic kinematic and geometric characteristics of turning technology of machining with tool with helical cutting edge. The final mathematical formula is deduced from graphic sketch of turning process and consequently identified using all the known geometric and kinematic parameters. This formula can be used to theoretic evaluation of geometric and cutting parameters influence on the quality of machined surface determined by roughness characteristic of theoretic parameter Rz.

  12. Gradient cuts and extremal edges in relative depth and figure-ground perception.

    PubMed

    Ghose, Tandra; Palmer, Stephen E

    2016-02-01

    Extremal edges (EEs) are borders consisting of luminance gradients along the projected edge of a partly self-occluding curved surface (e.g., a cylinder), with equiluminant contours (ELCs) that run approximately parallel to that edge. Gradient cuts (GCs) are similar luminance gradients with ELCs that intersect (are "cut" by) an edge that could be due to occlusion. EEs are strongly biased toward being seen as closer/figural surfaces (Palmer & Ghose, Psychological Science, 19(1), 77-83, 2008). Do GCs produce a complementary bias toward being seen as ground? Experiment 1 shows that, with EEs on the opposite side, GCs produce a ground bias that increases with increasing ELC angles between ELCs and the shared edge. Experiment 2 shows that, with flat surfaces on the opposite side, GCs do not produce a ground bias, suggesting that more than one factor may be operating. We suggest that two partially dissociable factors may operate for curved surfaces-ELC angle and 3-D surface convexity-that reinforce each other in the figural cues of EEs but compete with each other in GCs. Moreover, this figural bias is modulated by the presence of EEs and GCs, as specified by the ELC angle between ELCs and the shared contour.

  13. Cutting Edge Research in Homeopathy: HRI's second international research conference in Rome.

    PubMed

    Tournier, Alexander L; Roberts, E Rachel

    2016-02-01

    Rome, 3rd-5th June 2015, was the setting for the Homeopathy Research Institute's (HRI) second conference with the theme 'Cutting Edge Research in Homeopathy'. Attended by over 250 delegates from 39 countries, this event provided an intense two and a half day programme of presentations and a forum for the sharing of ideas and the creation of international scientific collaborations. With 35 oral presentations from leaders in the field, the scientific calibre of the programme was high and the content diverse. This report summarises the key themes underpinning the cutting edge data presented by the speakers, including six key-note presentations, covering advancements in both basic and clinical research. Given the clear commitment of the global homeopathic community to high quality research, the resounding success of both Barcelona 2013 and Rome 2015 HRI conferences, and the dedicated support of colleagues, the HRI moves confidently forward towards the next biennial conference.

  14. Enameloid microstructure of the serrated cutting edges in certain fossil carcharhiniform and lamniform sharks.

    PubMed

    Andreev, Plamen S

    2010-07-01

    The triple-layered enameloid organization of neoselachian teeth has proven to be a reliable systematic character of the group. This study uses scanning electron microscopy to investigate the orientation of the parallel enameloid bundles in the area of the serrated cutting edges in certain fossil elasmobranchs. The examined teeth come from two Upper Cretaceous Squalicorax species and the Upper Miocene carcharhiniforms Galeocerdo sp., Carcharhinus sp., and Hemipristis serra. The parallel bundles are revealed by surface etching, which removes the superficial shiny-layered enameloid. In the teeth of Squalicorax, the bundles around the cutting edge bend once, before they reach the serrations. The studied carcharhiniform species show a more complicated pattern with a change of parallel bundle course inside the serrations. H. serra teeth do not display the first bending of the bundles, whereas it was present in the other two carcharhiniforms. The course of the crystalline bundles in both Squalicorax species is not affected by the presence of the serrations, regardless of the twofold difference in tooth size between them. In the carcharhiniform species, the bended bundles occur within the primary and secondary serrations and are always associated with them. This feature might have functional significance by strengthening the cutting edge or could simply develop as a consequence of the enameloid mineralization around the individual serrae. (c) 2009 Wiley-Liss, Inc.

  15. Positive Edge Effects on Forest-Interior Cryptogams in Clear-Cuts

    PubMed Central

    Caruso, Alexandro; Rudolphi, Jörgen; Rydin, Håkan

    2011-01-01

    Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0–50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality

  16. Positive edge effects on forest-interior cryptogams in clear-cuts.

    PubMed

    Caruso, Alexandro; Rudolphi, Jörgen; Rydin, Håkan

    2011-01-01

    Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0-50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality

  17. Fuzzy Index to Evaluate Edge Detection in Digital Images.

    PubMed

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard's index (JI) and Dice's coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results.

  18. Fuzzy Index to Evaluate Edge Detection in Digital Images

    PubMed Central

    Perez-Ornelas, Felicitas; Mendoza, Olivia; Melin, Patricia; Castro, Juan R.; Rodriguez-Diaz, Antonio; Castillo, Oscar

    2015-01-01

    In literature, we can find different metrics to evaluate the detected edges in digital images, like Pratt's figure of merit (FOM), Jaccard’s index (JI) and Dice’s coefficient (DC). These metrics compare two images, the first one is the reference edges image, and the second one is the detected edges image. It is important to mention that all existing metrics must binarize images before their evaluation. Binarization step causes information to be lost because an incomplete image is being evaluated. In this paper, we propose a fuzzy index (FI) for edge evaluation that does not use a binarization step. In order to process all detected edges, images are represented in their fuzzy form and all calculations are made with fuzzy sets operators and fuzzy Euclidean distance between both images. Our proposed index is compared to the most used metrics using synthetic images, with good results. PMID:26115362

  19. Visible imaging of edge fluctuations in TFTR

    SciTech Connect

    Zweben, S.J.; Medley, S.S.

    1989-03-01

    Images of the visible light emission from the inner wall region of TFTR have been made using a rapidly gated, intensified TV camera. Strong ''filamentation'' of the neutral deuterium D..cap alpha.. light is observed when the camera gating time is <100 ..mu..sec during neutral-beam-heated discharges. These turbulent filaments vary in position randomly vs. time and have a poloidal wavelength of approx.3-5 cm which is much shorter than their parallel wavelength of approx.100 cm. A second and new type of edge fluctuation phenomenon, which we call a ''merfe,'' is also described. Merfes are a regular poloidal pattern of toroidally symmetric, small-scale marfes which move away from the inner midplane during the current decay after neutral beam injection. Some tentative interpretations of these two phenomena are presented. 27 refs., 8 figs.

  20. Augmented Endoscopic Images Overlaying Shape Changes in Bone Cutting Procedures

    PubMed Central

    2016-01-01

    In microendoscopic discectomy for spinal disorders, bone cutting procedures are performed in tight spaces while observing a small portion of the target structures. Although optical tracking systems are able to measure the tip of the surgical tool during surgery, the poor shape information available during surgery makes accurate cutting difficult, even if preoperative computed tomography and magnetic resonance images are used for reference. Shape estimation and visualization of the target structures are essential for accurate cutting. However, time-varying shape changes during cutting procedures are still challenging issues for intraoperative navigation. This paper introduces a concept of endoscopic image augmentation that overlays shape changes to support bone cutting procedures. This framework handles the history of the location of the measured drill tip as a volume label and visualizes the remains to be cut overlaid on the endoscopic image in real time. A cutting experiment was performed with volunteers, and the feasibility of this concept was examined using a clinical navigation system. The efficacy of the cutting aid was evaluated with respect to the shape similarity, total moved distance of a cutting tool, and required cutting time. The results of the experiments showed that cutting performance was significantly improved by the proposed framework. PMID:27584732

  1. Augmented Endoscopic Images Overlaying Shape Changes in Bone Cutting Procedures.

    PubMed

    Nakao, Megumi; Endo, Shota; Nakao, Shinichi; Yoshida, Munehito; Matsuda, Tetsuya

    2016-01-01

    In microendoscopic discectomy for spinal disorders, bone cutting procedures are performed in tight spaces while observing a small portion of the target structures. Although optical tracking systems are able to measure the tip of the surgical tool during surgery, the poor shape information available during surgery makes accurate cutting difficult, even if preoperative computed tomography and magnetic resonance images are used for reference. Shape estimation and visualization of the target structures are essential for accurate cutting. However, time-varying shape changes during cutting procedures are still challenging issues for intraoperative navigation. This paper introduces a concept of endoscopic image augmentation that overlays shape changes to support bone cutting procedures. This framework handles the history of the location of the measured drill tip as a volume label and visualizes the remains to be cut overlaid on the endoscopic image in real time. A cutting experiment was performed with volunteers, and the feasibility of this concept was examined using a clinical navigation system. The efficacy of the cutting aid was evaluated with respect to the shape similarity, total moved distance of a cutting tool, and required cutting time. The results of the experiments showed that cutting performance was significantly improved by the proposed framework.

  2. Edge Detection in Digital Images Using Dispersive Phase Stretch Transform

    PubMed Central

    Asghari, Mohammad H.; Jalali, Bahram

    2015-01-01

    We describe a new computational approach to edge detection and its application to biomedical images. Our digital algorithm transforms the image by emulating the propagation of light through a physical medium with specific warped diffractive property. We show that the output phase of the transform reveals transitions in image intensity and can be used for edge detection. PMID:25878656

  3. Sliding mean edge estimation. [in digital image processing

    NASA Technical Reports Server (NTRS)

    Ford, G. E.

    1978-01-01

    A method for determining the locations of the major edges of objects in digital images is presented. The method is based on an algorithm utilizing maximum likelihood concepts. An image line-scan interval is processed to determine if an edge exists within the interval and its location. The proposed algorithm has demonstrated good results even in noisy images.

  4. Built-up edge effect on tool wear when turning steels at low cutting speed

    NASA Astrophysics Data System (ADS)

    Cassier, Zulay; Prato, Yidney; Muñoz-Escalona, Patricia

    2004-10-01

    In any machining process, it is very important to control the cutting variables used during the process because these will affect, for example, tool life and workpiece surface roughness. Since the built-up edge (BUE) increases the wear of the tool and affects the surface roughness of the workpiece, the study of this phenomenon is very important in predicting and minimizing the wear of a cutting tool. This research studies the influence of the BUE formation for coated carbide tools when turning medium- and high-strength steels. Different mathematical expressions were obtained to quantify this effect. Mathematical expressions for uncoated carbide tools were not possible to obtain, due to the fact that for these tools an increase in the wear and their premature fracture was observed.

  5. [Modern hearing-aids at the cutting edge of microelectronics. Increased possibilities for individual customization].

    PubMed

    Arlinger, S

    1999-08-25

    The development of modern hearing aids has been so great that they now represent the cutting edge of micro-electronics. Flexibility has been enhanced by computer-aided programming of the devices, and particularly by digital signal processing, developments which enable improved customization. Increased knowledge of the pathophysiology of the auditory system, fundamental processes in central auditory pathways, and cognitive function enable technological developments to be exploited, thus enhancing our ability to cope with an increasingly broad spectrum of hearing impairment, ranging from mild high-frequency loss to severe loss across the entire frequency range.

  6. Distribution of contact loads over the flank-land of the cutter with a rounded cutting edge

    NASA Astrophysics Data System (ADS)

    Kozlov, V.; Gerasimov, A.; Kim, A.

    2016-04-01

    In this paper, contact conditions between a tool and a workpiece material for wear-simulating turning by a cutter with a sharp-cornered edge and with a rounded cutting edge are analysed. The results of the experimental study of specific contact load distribution over the artificial flank wear-land of the cutter in free orthogonal turning of the disk from titanium alloy (Ti6Al2Mo2Cr), ductile (63Cu) and brittle (57Cu1Al3Mn) brasses are described. Investigations were carried out by the method of ‘split cutter’ and by the method of the artificial flank-land of variable width. The experiments with a variable feed rate and a cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge the highest normal contact load (σh max = 3400…2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with the length of 0.2… 0.6 mm. At a distance from the cutting edge, the value of specific normal contact load is dramatically reduced to 1100…500 MPa. The character of normal contact load for a rounded cutting edge is different -it is uniform, and its value is approximately 2 times smaller compared to machining with a sharp-cornered cutting edge. In author’s opinion it is connected with generation of a seizure zone in a chip formation region and explains the capacity of highly worn-out cutting tools for titanium alloys machining. The paper analyses the distribution of tangential contact loads over the flank land, which pattern differs considerably for machining with a sharp-cornered edge and with a rounded cutting edge. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (specific contact load as a stress σ or τ) hf - the width of the flank wear land (chamfer) of the cutting tool, flank wear land can be natural or artificial like the one in this paper [mm]; xh - distance from the cutting edge on the surface of the flank-land [mm

  7. Blind image deblurring with edge enhancing total variation regularization

    NASA Astrophysics Data System (ADS)

    Shi, Yu; Hong, Hanyu; Song, Jie; Hua, Xia

    2015-04-01

    Blind image deblurring is an important issue. In this paper, we focus on solving this issue by constrained regularization method. Motivated by the importance of edges to visual perception, the edge-enhancing indicator is introduced to constrain the total variation regularization, and the bilateral filter is used for edge-preserving smoothing. The proposed edge enhancing regularization method aims to smooth preferably within each region and preserve edges. Experiments on simulated and real motion blurred images show that the proposed method is competitive with recent state-of-the-art total variation methods.

  8. Edge mode spectroscopy and imaging for film edge properties in magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    McMichael, Robert

    2014-03-01

    Lithography is an act of violence. Often, films are almost entirely obliterated by patterning, leaving only nanostructures behind with film edges that have borne the brunt of the damage, edges that carry with them the scars of energetic ion bombardment, reactive ions, liftoff and exposure to ambient conditions. In this talk, I will present a variation on ferromagnetic resonance force microscopy that can provide insight into the magnetic properties of film edges in magnetic nanostructures. The method relies on the non-uniformity of the magnetic field in patterned-film nanostructures that are magnetized in-plane, specifically, the low-field regions that form near where the magnetization is directed normal to the edge. In these regions, localized precession forms as trapped spin wave modes, and the resonance condition of these modes serves as an indicator of the edge properties. I will present modeling and measurements on a 500 nm diameter, 25 nm thick Permalloy disk to illustrate the method. Micromagnetic modeling of this disk predicts a main mode that is nearly uniform across the sample and three localized edge modes with higher resonance fields. The spectra measured with various tip positions and mode imaging are consistent with the modeling results. In addition to a strong center mode, three distinct edge modes are observed when the tip is near the disk edge. For a symmetric disk, the modeling predicts that the edge mode resonances are identical on the two opposite edges. However, the measured edge mode resonances on opposite edges of the disk are detected at different resonance fields, suggesting inhomogeneity of the edge properties. By rotating the applied field, we control the position of the localized edge mode along the edge of the disk and confirm that the edge mode resonance field has a strong angular dependence, showing that edge mode properties can vary significantly in a nominally circular disk.

  9. Adaptively wavelet-based image denoising algorithm with edge preserving

    NASA Astrophysics Data System (ADS)

    Tan, Yihua; Tian, Jinwen; Liu, Jian

    2006-02-01

    A new wavelet-based image denoising algorithm, which exploits the edge information hidden in the corrupted image, is presented. Firstly, a canny-like edge detector identifies the edges in each subband. Secondly, multiplying the wavelet coefficients in neighboring scales is implemented to suppress the noise while magnifying the edge information, and the result is utilized to exclude the fake edges. The isolated edge pixel is also identified as noise. Unlike the thresholding method, after that we use local window filter in the wavelet domain to remove noise in which the variance estimation is elaborated to utilize the edge information. This method is adaptive to local image details, and can achieve better performance than the methods of state of the art.

  10. Image segmentation on adaptive edge-preserving smoothing

    NASA Astrophysics Data System (ADS)

    He, Kun; Wang, Dan; Zheng, Xiuqing

    2016-09-01

    Nowadays, typical active contour models are widely applied in image segmentation. However, they perform badly on real images with inhomogeneous subregions. In order to overcome the drawback, this paper proposes an edge-preserving smoothing image segmentation algorithm. At first, this paper analyzes the edge-preserving smoothing conditions for image segmentation and constructs an edge-preserving smoothing model inspired by total variation. The proposed model has the ability to smooth inhomogeneous subregions and preserve edges. Then, a kind of clustering algorithm, which reasonably trades off edge-preserving and subregion-smoothing according to the local information, is employed to learn the edge-preserving parameter adaptively. At last, according to the confidence level of segmentation subregions, this paper constructs a smoothing convergence condition to avoid oversmoothing. Experiments indicate that the proposed algorithm has superior performance in precision, recall, and F-measure compared with other segmentation algorithms, and it is insensitive to noise and inhomogeneous-regions.

  11. Bacterial foraging based edge detection for cell image segmentation.

    PubMed

    Pan, Yongsheng; Zhou, Tao; Xia, Yong

    2015-01-01

    Edge detection is the most popular and common choices for cell image segmentation, in which local searching strategies are commonly used. In spite of their computational efficiency, traditional edge detectors, however, may either produce discontinued edges or rely heavily on initializations. In this paper, we propose a bacterial foraging based edge detection (BFED) algorithm for cell image segmentation. We model the gradients of intensities as the nutrient concentration and propel bacteria to forage along nutrient-rich locations via mimicking the behavior of Escherichia coli, including the chemotaxis, swarming, reproduction, elimination and dispersal. As a nature-inspired evolutionary technique, this algorithm can identify the desired edges and mark them as the tracks of bacteria. We have evaluated the proposed algorithm against the Canny, SUSAN, Verma's and an active contour model (ACM) based edge detectors on both synthetic and real cell images. Our results suggest that the BFED algorithm can identify boundaries more effectively and provide more accurate cell image segmentation.

  12. Depth Edge Filtering Using Parameterized Structured Light Imaging

    PubMed Central

    Zheng, Ziqi; Bae, Seho; Yi, Juneho

    2017-01-01

    This research features parameterized depth edge detection using structured light imaging that exploits a single color stripes pattern and an associated binary stripes pattern. By parameterized depth edge detection, we refer to the detection of all depth edges in a given range of distances with depth difference greater or equal to a specific value. While previous research has not properly dealt with shadow regions, which result in double edges, we effectively remove shadow regions using statistical learning through effective identification of color stripes in the structured light images. We also provide a much simpler control of involved parameters. We have compared the depth edge filtering performance of our method with that of the state-of-the-art method and depth edge detection from the Kinect depth map. Experimental results clearly show that our method finds the desired depth edges most correctly while the other methods cannot. PMID:28368350

  13. Depth Edge Filtering Using Parameterized Structured Light Imaging.

    PubMed

    Zheng, Ziqi; Bae, Seho; Yi, Juneho

    2017-04-03

    This research features parameterized depth edge detection using structured light imaging that exploits a single color stripes pattern and an associated binary stripes pattern. By parameterized depth edge detection, we refer to the detection of all depth edges in a given range of distances with depth difference greater or equal to a specific value. While previous research has not properly dealt with shadow regions, which result in double edges, we effectively remove shadow regions using statistical learning through effective identification of color stripes in the structured light images. We also provide a much simpler control of involved parameters. We have compared the depth edge filtering performance of our method with that of the state-of-the-art method and depth edge detection from the Kinect depth map. Experimental results clearly show that our method finds the desired depth edges most correctly while the other methods cannot.

  14. Efficient method of image edge detection based on FSVM

    NASA Astrophysics Data System (ADS)

    Cai, Aiping; Xiong, Xiaomei

    2013-07-01

    For efficient object cover edge detection in digital images, this paper studied traditional methods and algorithm based on SVM. It analyzed Canny edge detection algorithm existed some pseudo-edge and poor anti-noise capability. In order to provide a reliable edge extraction method, propose a new detection algorithm based on FSVM. Which contains several steps: first, trains classify sample and gives the different membership function to different samples. Then, a new training sample is formed by increase the punishment some wrong sub-sample, and use the new FSVM classification model for train and test them. Finally the edges are extracted of the object image by using the model. Experimental result shows that good edge detection image will be obtained and adding noise experiments results show that this method has good anti-noise.

  15. Graph-cut Based Interactive Segmentation of 3D Materials-Science Images

    DTIC Science & Technology

    2014-04-26

    prior. While finding the global minimum to this cost is NP- hard , this cost has been shown to be minimizable to a local opti- mum using a graph-cut...regions, and use a SVM classifier [14] to learn which candi - dates are truly salient regions, and which are noise that can be ignored by the human... pre - sented as salient regions. Finally, when the user is presented 123 Author’s personal copy J. Waggoner et al. Image Canny edge detection ignoring

  16. Spectral segmentation of polygonized images with normalized cuts

    SciTech Connect

    Matsekh, Anna; Skurikhin, Alexei; Rosten, Edward

    2009-01-01

    We analyze numerical behavior of the eigenvectors corresponding to the lowest eigenvalues of the generalized graph Laplacians arising in the Normalized Cuts formulations of the image segmentation problem on coarse polygonal grids.

  17. Teaching about Climate Change and Energy with Online Materials and Workshops from On the Cutting Edge

    NASA Astrophysics Data System (ADS)

    Kirk, K. B.; Manduca, C. A.; Myers, J. D.; Loxsom, F.

    2009-12-01

    Global climate change and energy use are among the most relevant and pressing issues in today’s science curriculum, yet they are also complex topics to teach. The underlying science spans multiple disciplines and is quickly evolving. Moreover, a comprehensive treatment of climate change and energy use must also delve into perspectives not typically addressed in geosciences courses, such as public policy and economics. Thus, faculty attempting to address these timely issues face many challenges. To support faculty in teaching these subjects, the On the Cutting Edge faculty development program has created a series of websites and workshop opportunities to provide faculty with information and resources for teaching about climate and energy. A web-based collection of teaching materials was developed in conjunction with the On the Cutting Edge workshops “Teaching about Energy in Geoscience Courses: Current Research and Pedagogy.” The website is designed to provide faculty with examples, references and ideas for either incorporating energy topics into existing geoscience courses or for designing or refining a course about energy. The website contains a collection of over 30 classroom and lab activities contributed by faculty and covering such diverse topics as renewable energy, energy policy and energy conservation. Course descriptions and syllabi for energy courses address audiences ranging from introductory courses to advanced seminars. Other materials available on the website include a collection of visualizations and animations, a catalog of recommended books, presentations and related references from the teaching energy workshops, and ideas for novel approaches or new topics for teaching about energy in the geosciences. The Teaching Climate Change website hosts large collections of teaching materials spanning many different topics within climate change, climatology and meteorology. Classroom activities highlight diverse pedagogic approaches such as role

  18. Line Edge Detection and Characterization in SEM Images using Wavelets

    SciTech Connect

    Sun, W; Romagnoli, J A; Tringe, J W; L?tant, S E; Stroeve, P; Palazoglu, A

    2008-10-07

    Edge characterization has become increasingly important in nanotechnology due to the growing demand for precise nanoscale structure fabrication and assembly. Edge detection is often performed by thresholding the spatial information of a top-down image obtained by Scanning Electron Microscopy (SEM) or other surface characterization techniques. Results are highly dependent on an arbitrary threshold value, which makes it difficult to reveal the nature of the real surface and to compare results among images. In this paper, we present an alternative edge boundary detection technique based on the wavelet framework. Our results indicate that the method facilitates nano-scale edge detection and characterization, by providing a systematic threshold determination step.

  19. RETRACTED: The Virtual Cutting Edge: Adolescent Self-injury and YouTube.

    PubMed

    Garthe, C; Ouellette, L; Seamon, J P; Jones, J S

    2015-10-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Authors. We wish to retract the abstract "The Virtual Cutting Edge: Adolescent Self-injury and YouTube," published in the October 2015 issue of Annals. The abstract excessively borrowed from the text and methodology of a previous study published elsewhere.(1) All authors recognize the seriousness of this issue and apologize to the editors and readers of Annals. Jeffrey S. Jones, MD Chad Garthe, MD Lindsey Ouellette, MS Jason Seamon, DO Department of Emergency Medicine MSU College of Human Medicine Grand Rapids, MI 1. Lewis SP, Heath NL, St. Denis JM, et al. The scope of nonsuicidal self-injury on YouTube. Pediatrics. 2011;1127:e552-e557. Copyright © 2016. Published by Elsevier Inc.

  20. Conveying Cutting-Edge Discoveries to Nonscientists: Effective Communication with Media

    NASA Astrophysics Data System (ADS)

    Gupta, Nikhil; Hamilton, Kathleen; Chamot, Joshua

    2013-07-01

    The benefits of using information and news media for disseminating cutting-edge scientific discoveries to the public are well known. Taxpayers and lawmakers need to be informed about the implications of public investments, young students' interest can be molded toward science- and technology-based careers, and public awareness of important issues can be raised by effectively using media. However, communication with news media is different from the means commonly used by scientists—journal publications and conference presentations. This article is intended to provide information on three basic aspects of media interactions—why, what, and how to communicate. The increasing importance of this mode of dissemination in this information age cannot be ignored; rather, it can be effectively utilized for educating a wider population base.

  1. Virtual Workshop Experiences for Faculty: Lessons Learned from On the Cutting Edge

    NASA Astrophysics Data System (ADS)

    McDaris, J. R.; Kirk, K. B.; Mogk, D. W.; Bruckner, M. Z.

    2010-12-01

    The On the Cutting Edge professional development program for geoscience faculty has begun offering online workshops as a supplement to its face-to-face workshop series. Following a few initial forays since 2005, Cutting Edge launched a suite of four virtual workshops in 2010: Teaching Geoscience with Service Learning, Understanding the Deep Earth, Designing Effective and Innovative Courses in the Geosciences, and Teaching Geoscience Online. Each workshop was presented over 1-2 weeks and included pre-workshop web postings, synchronous whole-group presentations, live small-group discussions, asynchronous input via threaded discussions or editable web pages, and personal time for reflection and writing. Synchronous sessions were facilitated through the Elluminate software platform which includes tools for viewing presentations, screen sharing, real-time participant response, and an ongoing chat-room discussion. Audio was provided through a separate telephone conference service. In addition, many asynchronous conversations on workshop topics were held via a threaded discussion board on the Cutting Edge website and in Wiki-like, editable web pages designed to support collaborative work. A number of challenges to running online workshops exist, primarily involving participants’ time management. It is difficult for participants to set aside enough time to complete workshop activities when they are still enmeshed in their everyday lives. It also requires new skills for speakers, participants and support staff to prepare web-based materials and navigate the technology required for the online presentations. But there are also a number of opportunities presented by these experiences. With no travel needed, an online workshop is less expensive for participants, which allows Cutting Edge to extend its commitment to providing workshop materials to a wider audience of interested faculty. Also, synchronous sessions can be recorded and posted on the website for broader community

  2. Cutting-edge issues in autoimmunity and allergy of the digestive system.

    PubMed

    Selmi, Carlo

    2012-06-01

    Autoimmunity and allergy involving the digestive system may be considered as paradigmatic for numerous common themes of complex diseases secondary to tolerance breakdown. Among gastrointestinal autoimmune diseases, for example, we encounter diseases in which a clear environmental trigger is identified (i.e., celiac disease), serum autoantibodies are most specific (i.e., primary biliary cirrhosis), or in which the disease pathophysiology is clearly understood (i.e., autoimmune gastritis). Similarly, it is intriguing that the gastrointestinal tract and the liver circulation represent the crucial environment for the development of immune tolerance. This issue is dedicated to the discussion of recent concepts while identifying two major common issues, i.e., the need for serum biomarkers and the role of vitamin D. Other common themes characterize the etiology and effector mechanisms of these and other autoimmune diseases and are discussed in each cutting-edge overview.

  3. The Edge Detectors Suitable for Retinal OCT Image Segmentation

    PubMed Central

    Yang, Jing; Gao, Qian; Zhou, Sheng

    2017-01-01

    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.

  4. Tool holder for preparation and inspection of a radiused edge cutting tool

    DOEpatents

    Asmanes, Charles

    1979-01-01

    A tool holding fixture is provided for removably holding a radiused edge cutting tool in a tool edge lapping apparatus. The fixture allows the operator to preset the lapping radius and angle before the tool holder is placed in the fixture and the holder may be removed from the lapping apparatus to inspect the tool and simply replaced in the fixture to continue lapping in accordance with a precise alignment without realignment of the tool relative to the lap. The tool holder includes a pair of self aligning bearings in the form of precision formed steel balls connected together by a rigid shaft. The tool is held by an arm extending from the shaft and the balls set in fixed position bearing cups and the holder is oscillated back and forth about a fixed axis of rotation to lap the tool radius by means of a reversibly driven belt-pulley arrangement coupled to the shaft between the bearings. To temporarily remove the holder, the drive belt is slipped over the rearward end of the holder and the holder is lifted out of the bearing cups.

  5. An edge detection method for strong noisy image using shearlets

    NASA Astrophysics Data System (ADS)

    Li, Yuming; Cao, Hanqiang; Xu, Zijian

    2011-11-01

    Numerous edge detection methods have been proposed to detect image edges. However, these methods are not very effective in detecting edges in strong noisy images. Recent years, multiscale analysis has been introduced to the realm of image processing. As the third generation wavelet, shearlets have their own superiority. Anisotropic dilation operator and shear operator are introduced to overcome the shortcomings of traditional wavelets. Because of their sensitivity to directions, shearlets are apt to do the job of edge detection. Based on shearlets, in this paper, a new edge detection method is proposed. The main idea about this new method is combining the shearlet denoising method with the edge detecting method based on shearlets. Analyzing results show that edges are characterized as zerocrossing points in shearlet domain and can be extracted from shearlet transform coefficients by detecting zero crossing points and using boundary tracking method. Many experiments are conducted to test this novel approach and we also compare Sobel, Log and Canny operators with this new method. Experiments demonstrate that when an image existing high deviation Gaussian noise, this method are much better than ordinary edge detection operators in time domain.

  6. Colorimetry-based edge preservation approach for color image enhancement

    NASA Astrophysics Data System (ADS)

    Suresh, Merugu; Jain, Kamal

    2016-07-01

    "Subpixel-based downsampling" is an approach that can implicitly enhance perceptible image resolution of a downsampled image by managing subpixel-level representation preferably with individual pixel. A subpixel-level representation for color image sample at edge region and color image representation is focused with the problem of directional filtration based on horizontal and vertical orientations using colorimetric color space with the help of saturation and desaturation pixels. A diagonal tracing algorithm and an edge preserving approach with colorimetric color space were used for color image enhancement. Since, there exist high variations at the edge regions, it could not be considered as constant or zero, and when these variations are random the need to compensate these to minimum value and then process for image representation. Finally, the results of the proposed method show much better image information as compared with traditional direct pixel-based methods with increased luminance and chrominance resolutions.

  7. Edge enhancement of color images using a digital micromirror device.

    PubMed

    Di Martino, J Matías; Flores, Jorge L; Ayubi, Gastón A; Alonso, Julia R; Fernández, Ariel; Ferrari, José A

    2012-06-01

    A method for orientation-selective enhancement of edges in color images is proposed. The method utilizes the capacity of digital micromirror devices to generate a positive and a negative color replica of the image used as input. When both images are slightly displaced and imagined together, one obtains an image with enhanced edges. The proposed technique does not require a coherent light source or precise alignment. The proposed method could be potentially useful for processing large image sequences in real time. Validation experiments are presented.

  8. Tangential 2-D Edge Imaging for GPI and Edge/Impurity Modeling

    SciTech Connect

    Dr. Ricardo Maqueda; Dr. Fred M. Levinton

    2011-12-23

    Nova Photonics, Inc. has a collaborative effort at the National Spherical Torus Experiment (NSTX). This collaboration, based on fast imaging of visible phenomena, has provided key insights on edge turbulence, intermittency, and edge phenomena such as edge localized modes (ELMs) and multi-faceted axisymmetric radiation from the edge (MARFE). Studies have been performed in all these areas. The edge turbulence/intermittency studies make use of the Gas Puff Imaging diagnostic developed by the Principal Investigator (Ricardo Maqueda) together with colleagues from PPPL. This effort is part of the International Tokamak Physics Activity (ITPA) edge, scrape-off layer and divertor group joint activity (DSOL-15: Inter-machine comparison of blob characteristics). The edge turbulence/blob study has been extended from the current location near the midplane of the device to the lower divertor region of NSTX. The goal of this effort was to study turbulence born blobs in the vicinity of the X-point region and their circuit closure on divertor sheaths or high density regions in the divertor. In the area of ELMs and MARFEs we have studied and characterized the mode structure and evolution of the ELM types observed in NSTX, as well as the study of the observed interaction between MARFEs and ELMs. This interaction could have substantial implications for future devices where radiative divertor regions are required to maintain detachment from the divertor plasma facing components.

  9. Blind Image Inpainting Based on TV Model and Edge Detection

    NASA Astrophysics Data System (ADS)

    Wang, Xin-Yu; Deng, Liang-Jian

    Blind image inpainting is an approach to estimate the original image, when there is no or little knowledge of the degraded process. In this paper, the algorithm of blind image inpainting is based on edge detection methods to generate one inpainting mask H automatically. And then we combine the inpainting mask H with a TV model to get image blind inpainted. Experiment results demonstrate that the proposed algorithms is effective with application to both the synthetic and real-world images.

  10. Coastline detection in SAR images using discriminant cuts segmentation

    NASA Astrophysics Data System (ADS)

    Ding, Xianwen; Zou, Xiaolin; Yu, Tan

    2016-11-01

    The discriminant cut algorithm is used to detect coastlines in synthetic aperture radar (SAR) images. The proposed approach is a region-based one, which is able to capture and utilize spatial information in the image. The real SAR images, e.g. ALOS-1 PALSAR and COSMO-SkyMed SAR images, together with in-situ GPS data were collected and used to validate the performance of the proposed approach for coastline detection in SAR images. The accuracy is better than 4 times the image resolution. The efficiency is also tested.

  11. At the Cutting Edge: Recent Research on Learning To Read and Spell. Studies in Education Series, No. 53.

    ERIC Educational Resources Information Center

    Nicholson, Tom

    Taking into account what research says about getting all children off to a better start in becoming literate, this booklet discusses recent "cutting-edge" research in the area of reading and spelling acquisition, focusing on the practical implications. The first part of the booklet notes what happens in the homes of early readers,…

  12. PET image reconstruction with anatomical edge guided level set prior

    NASA Astrophysics Data System (ADS)

    Cheng-Liao, Jinxiu; Qi, Jinyi

    2011-11-01

    Acquiring both anatomical and functional images during one scan, PET/CT systems improve the ability to detect and localize abnormal uptakes. In addition, CT images provide anatomical boundary information that can be used to regularize positron emission tomography (PET) images. Here we propose a new approach to maximum a posteriori reconstruction of PET images with a level set prior guided by anatomical edges. The image prior models both the smoothness of PET images and the similarity between functional boundaries in PET and anatomical boundaries in CT. Level set functions (LSFs) are used to represent smooth and closed functional boundaries. The proposed method does not assume an exact match between PET and CT boundaries. Instead, it encourages similarity between the two boundaries, while allowing different region definition in PET images to accommodate possible signal and position mismatch between functional and anatomical images. While the functional boundaries are guaranteed to be closed by the LSFs, the proposed method does not require closed anatomical boundaries and can utilize incomplete edges obtained from an automatic edge detection algorithm. We conducted computer simulations to evaluate the performance of the proposed method. Two digital phantoms were constructed based on the Digimouse data and a human CT image, respectively. Anatomical edges were extracted automatically from the CT images. Tumors were simulated in the PET phantoms with different mismatched anatomical boundaries. Compared with existing methods, the new method achieved better bias-variance performance. The proposed method was also applied to real mouse data and achieved higher contrast than other methods.

  13. Cutting-edge mass spectrometry characterization of originator, biosimilar and biobetter antibodies.

    PubMed

    Beck, Alain; Debaene, François; Diemer, Hélène; Wagner-Rousset, Elsa; Colas, Olivier; Van Dorsselaer, Alain; Cianférani, Sarah

    2015-02-01

    The approval process for antibody biosimilars relies primarily on comprehensive analytical data to establish comparability and high similarity with the originator. Mass spectrometry (MS) in combination with liquid chromatography (LC) and electrophoretic methods are the corner stone for comparability and biosimilarity evaluation. In this special feature we report head-to-head comparison of trastuzumab and cetuximab with corresponding biosimilar and biobetter candidates based on cutting-edge mass spectrometry techniques such as native MS and ion-mobility MS at different levels (top, middle and bottom). In addition, we discuss the advantages and the limitations of sample preparation and enzymatic digestion, middle-up and -down strategies and the use of hydrogen/deuterium exchange followed by MS (HDX-MS). Last but not least, emerging separation methods combined to MS such as capillary zone electrophoresis-tandem MS (CESI-MS/MS), electron transfer dissociation (ETD), top down-sequencing (TDS) and high-resolution MS (HR-MS) that complete the panel of state-of-the-art MS-based options for comparability and biosimilarity evaluation are presented. Copyright © 2015 John Wiley & Sons, Ltd.

  14. A Cutting-Edge Education: Incorporating Nano into the Undergraduate Curricula.

    NASA Astrophysics Data System (ADS)

    Zenner, Greta M.

    2008-03-01

    The Interdisciplinary Education Group (IEG) of the Materials Research Science and Engineering Center (MRSEC) on Nanostructured Interfaces at the University of Wisconsin-Madison (UW) develops and uses hands-on, interactive education and outreach materials to engage a variety of audiences in learning about nanotechnology and advanced materials. Many of the education products created are inspired by UW MRSEC research; and faculty, staff, and students regularly contribute to the IEG's work to share nanotechnology with a broader audience. The UW MRSEC has developed numerous teaching modules, labs, and education resources devoted to nanotechnology concepts, and many of these materials have been integrated into key introductory and advanced undergraduate courses at UW and other institutions, including small liberal arts colleges and community colleges. This effort has taken place through both the creation of new courses and the modification of existing courses to include cutting-edge content based on current research and emerging applications in nanotechnology. In this talk, I will present some of the new instructional materials we have developed based on advances in nanoscale science and technology, the implementation and integration of these materials into undergraduate curricula, and an overview of the UW MRSEC education efforts.

  15. Sharpening the cutting edge: additional considerations for the UK debates on embryonic interventions for mitochondrial diseases.

    PubMed

    Haimes, Erica; Taylor, Ken

    2017-12-01

    In October 2015 the UK enacted legislation to permit the clinical use of two cutting edge germline-altering, IVF-based embryonic techniques: pronuclear transfer and maternal spindle transfer (PNT and MST). The aim is to use these techniques to prevent the maternal transmission of serious mitochondrial diseases. Major claims have been made about the quality of the debates that preceded this legislation and the significance of those debates for UK decision-making on other biotechnologies, as well as for other countries considering similar legislation. In this article we conduct a systematic analysis of those UK debates and suggest that claims about their quality are over-stated. We identify, and analyse in detail, ten areas where greater clarity, depth and nuance would have produced sharper understandings of the contributions, limitations and wider social impacts of these mitochondrial interventions. We explore the implications of these additional considerations for (i) the protection of all parties involved, should the techniques transfer to clinical applications; (ii) the legitimacy of focussing on short-term gains for individuals over public health considerations, and (iii) the maintenance and improvement of public trust in medical biotechnologies. We conclude that a more measured evaluation of the content and quality of the UK debates is important and timely: such a critique provides a clearer understanding of the possible, but specific, contributions of these interventions, both in the UK and elsewhere; also, these additional insights can now inform the emerging processes of implementation, regulation and practice of mitochondrial interventions.

  16. Pixon Based Image Denoising Scheme by Preserving Exact Edge Locations

    NASA Astrophysics Data System (ADS)

    Srikrishna, Atluri; Reddy, B. Eswara; Pompapathi, Manasani

    2016-09-01

    Denoising of an image is an essential step in many image processing applications. In any image de-noising algorithm, it is a major concern to keep interesting structures of the image like abrupt changes in image intensity values (edges). In this paper an efficient algorithm for image de-noising is proposed that obtains integrated and consecutive original image from noisy image using diffusion equations in pixon domain. The process mainly consists of two steps. In first step, the pixons for noisy image are obtained by using K-means clustering process and next step includes applying diffusion equations on the pixonal model of the image to obtain new intensity values for the restored image. The process has been applied on a variety of standard images and the objective fidelity has been compared with existing algorithms. The experimental results show that the proposed algorithm has a better performance by preserving edge details compared in terms of Figure of Merit and improved Peak-to-Signal-Noise-Ratio value. The proposed method brings out a denoising technique which preserves edge details.

  17. ESIM: Edge Similarity for Screen Content Image Quality Assessment.

    PubMed

    Ni, Zhangkai; Ma, Lin; Zeng, Huanqiang; Chen, Jing; Cai, Canhui; Ma, Kai-Kuang

    2017-10-01

    In this paper, an accurate full-reference image quality assessment (IQA) model developed for assessing screen content images (SCIs), called the edge similarity (ESIM), is proposed. It is inspired by the fact that the human visual system (HVS) is highly sensitive to edges that are often encountered in SCIs; therefore, essential edge features are extracted and exploited for conducting IQA for the SCIs. The key novelty of the proposed ESIM lies in the extraction and use of three salient edge features-i.e., edge contrast, edge width, and edge direction. The first two attributes are simultaneously generated from the input SCI based on a parametric edge model, while the last one is derived directly from the input SCI. The extraction of these three features will be performed for the reference SCI and the distorted SCI, individually. The degree of similarity measured for each above-mentioned edge attribute is then computed independently, followed by combining them together using our proposed edge-width pooling strategy to generate the final ESIM score. To conduct the performance evaluation of our proposed ESIM model, a new and the largest SCI database (denoted as SCID) is established in our work and made to the public for download. Our database contains 1800 distorted SCIs that are generated from 40 reference SCIs. For each SCI, nine distortion types are investigated, and five degradation levels are produced for each distortion type. Extensive simulation results have clearly shown that the proposed ESIM model is more consistent with the perception of the HVS on the evaluation of distorted SCIs than the multiple state-of-the-art IQA methods.

  18. Edge passivated charge-coupled device image sensor

    NASA Technical Reports Server (NTRS)

    Kosonocky, Walter F. (Inventor); Elabd, Hammam (Inventor)

    1987-01-01

    A charge-coupled device (CCD) image sensor includes in a substrate of single crystalline silicon of one conductivity type an array of a plurality of spaced, parallel channel regions of the opposite conductivity type extending along one major surface of the substrate. A plurality of parallel conductive gates are over the one major surface of the substrate and extend transversely across the channel regions. The outermost channel regions of the array are positioned adjacent edges of the substrate so that a plurality of the image sensors can be mounted in edge-to-edge relation with the channel regions of the various sensors being close together. The sensor includes passivating means between each outermost channel region and the adjacent edge to prevent charge carriers generated by the edge from being injected into the outermost channel region. The passivating means includes a highly conductive drain region of a conductivity type opposite to that of the substrate within the substrate and extending along the one major surface between the outermost channel region and the edge. Also, a highly conductive region of the same conductivity type as the substrate is on the substrate and extends along the one major surface directly at the edge.

  19. Automatic comic page image understanding based on edge segment analysis

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Wang, Yongtao; Tang, Zhi; Li, Luyuan; Gao, Liangcai

    2013-12-01

    Comic page image understanding aims to analyse the layout of the comic page images by detecting the storyboards and identifying the reading order automatically. It is the key technique to produce the digital comic documents suitable for reading on mobile devices. In this paper, we propose a novel comic page image understanding method based on edge segment analysis. First, we propose an efficient edge point chaining method to extract Canny edge segments (i.e., contiguous chains of Canny edge points) from the input comic page image; second, we propose a top-down scheme to detect line segments within each obtained edge segment; third, we develop a novel method to detect the storyboards by selecting the border lines and further identify the reading order of these storyboards. The proposed method is performed on a data set consisting of 2000 comic page images from ten printed comic series. The experimental results demonstrate that the proposed method achieves satisfactory results on different comics and outperforms the existing methods.

  20. Synthetic Aperture Microwave Imaging (SAMI) of the plasma edge on NSTX-U

    NASA Astrophysics Data System (ADS)

    Vann, Roddy; Taylor, Gary; Brunner, Jakob; Ellis, Bob; Thomas, David

    2016-10-01

    The Synthetic Aperture Microwave Imaging (SAMI) system is a unique phased-array microwave camera with a +/-40° field of view in both directions. It can image cut-off surfaces corresponding to frequencies in the range 10-34.5GHz; these surfaces are typically in the plasma edge. SAMI operates in two modes: either imaging thermal emission from the plasma (often modified by its interaction with the plasma edge e.g. via BXO mode conversion) or ``active probing'' i.e. injecting a broad beam at the plasma surface and imaging the reflected/back-scattered signal. SAMI was successfully pioneered on the Mega-Amp Spherical Tokamak (MAST) at Culham Centre for Fusion Energy. SAMI has now been installed and commissioned on the National Spherical Torus Experiment Upgrade (NSTX-U) at Princeton Plasma Physics Laboratory. The firmware has been upgraded to include real-time digital filtering, which enables continuous acquisition of the Doppler back-scattered active probing data. In this poster we shall present SAMI's analysis of the plasma edge on NSTX-U including measurements of the edge pitch angle on NSTX-U using SAMI's unique 2-D Doppler-backscattering capability.

  1. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    PubMed

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  2. Wavelet domain image restoration with adaptive edge-preserving regularization.

    PubMed

    Belge, M; Kilmer, M E; Miller, E L

    2000-01-01

    In this paper, we consider a wavelet based edge-preserving regularization scheme for use in linear image restoration problems. Our efforts build on a collection of mathematical results indicating that wavelets are especially useful for representing functions that contain discontinuities (i.e., edges in two dimensions or jumps in one dimension). We interpret the resulting theory in a statistical signal processing framework and obtain a highly flexible framework for adapting the degree of regularization to the local structure of the underlying image. In particular, we are able to adapt quite easily to scale-varying and orientation-varying features in the image while simultaneously retaining the edge preservation properties of the regularizer. We demonstrate a half-quadratic algorithm for obtaining the restorations from observed data.

  3. Liver ultrasound image classification by using fractal dimension of edge

    NASA Astrophysics Data System (ADS)

    Moldovanu, Simona; Bibicu, Dorin; Moraru, Luminita

    2012-08-01

    Medical ultrasound image edge detection is an important component in increasing the number of application of segmentation, and hence it has been subject of many studies in the literature. In this study, we have classified the liver ultrasound images (US) combining Canny and Sobel edge detectors with fractal analysis in order to provide an indicator about of the US images roughness. We intend to provide a classification rule of the focal liver lesions as: cirrhotic liver, liver hemangioma and healthy liver. For edges detection the Canny and Sobel operators were used. Fractal analyses have been applied for texture analysis and classification of focal liver lesions according to fractal dimension (FD) determined by using the Box Counting method. To assess the performance and accuracy rate of the proposed method the contrast-to-noise (CNR) is analyzed.

  4. Edge-Preserving PET Image Reconstruction Using Trust Optimization Transfer

    PubMed Central

    Wang, Guobao; Qi, Jinyi

    2014-01-01

    Iterative image reconstruction for positron emission tomography (PET) can improve image quality by using spatial regularization. The most commonly used quadratic penalty often over-smoothes sharp edges and fine features in reconstructed images, while non-quadratic penalties can preserve edges and achieve higher contrast recovery. Existing optimization algorithms such as the expectation maximization (EM) and preconditioned conjugate gradient (PCG) algorithms work well for the quadratic penalty, but are less efficient for high-curvature or non-smooth edge-preserving regularizations. This paper proposes a new algorithm to accelerate edge-preserving image reconstruction by using two strategies: trust surrogate and optimization transfer descent. Trust surrogate approximates the original penalty by a smoother function at each iteration, but guarantees the algorithm to descend monotonically; Optimization transfer descent accelerates a conventional optimization transfer algorithm by using conjugate gradient and line search. Results of computer simulations and real 3D data show that the proposed algorithm converges much faster than the conventional EM and PCG for smooth edge-preserving regularization and can also be more efficient than the current state-of-art algorithms for the non-smooth ℓ1 regularization. PMID:25438302

  5. Edge-preserving PET image reconstruction using trust optimization transfer.

    PubMed

    Wang, Guobao; Qi, Jinyi

    2015-04-01

    Iterative image reconstruction for positron emission tomography can improve image quality by using spatial regularization. The most commonly used quadratic penalty often oversmoothes sharp edges and fine features in reconstructed images, while nonquadratic penalties can preserve edges and achieve higher contrast recovery. Existing optimization algorithms such as the expectation maximization (EM) and preconditioned conjugate gradient (PCG) algorithms work well for the quadratic penalty, but are less efficient for high-curvature or nonsmooth edge-preserving regularizations. This paper proposes a new algorithm to accelerate edge-preserving image reconstruction by using two strategies: trust surrogate and optimization transfer descent. Trust surrogate approximates the original penalty by a smoother function at each iteration, but guarantees the algorithm to descend monotonically; Optimization transfer descent accelerates a conventional optimization transfer algorithm by using conjugate gradient and line search. Results of computer simulations and real 3-D data show that the proposed algorithm converges much faster than the conventional EM and PCG for smooth edge-preserving regularization and can also be more efficient than the current state-of-art algorithms for the nonsmooth l1 regularization.

  6. Influence of the cutting edge angle of a titanium instrument on chip formation in the machining of trabecular and cortical bone.

    PubMed

    von See, Constantin; Stoetzer, Marcus; Ruecker, Martin; Wagner, Max; Schumann, Paul; Gellrich, Nils-Claudius

    2014-01-01

    The placement of self-tapping implants is associated with microfractures and the formation of bone chips along the cutting flutes. This study was conducted to investigate the effect of different cutting edge angles on chip formation during the machining of trabecular and cortical bone using instruments with a rough titanium surface. Mandibular cortical and trabecular bone specimens were obtained from freshly slaughtered domestic pigs. A predefined thrust force was applied to the specimens. Four specially designed cutting instruments that simulated dental implants and had a rough titanium surface were allowed to complete one full revolution at cutting edge angles of 55, 65, 75, and 85 degrees, respectively. Torque and thrust were measured during the cutting process. Bone chips were measured and weighed under a microscope. Different cutting edge angles did not lead to significant differences in torque. The lowest torque values were measured when the cutting edges were positioned at 65 degrees in trabecular bone and at 85 degrees in cortical bone. Bone chips were significantly larger and heavier at angles of 55 and 65 degrees than at angles of 75 and 85 degrees in trabecular bone. Instruments with a rough titanium surface show considerable angle-dependent differences in chip formation. In addition to bone density, the angle of the cutting edges should be taken into consideration during the placement of dental implants. Good results were obtained when the cutting edges were positioned at an angle of 65 degrees. This angle can have positive effects on osseointegration.

  7. From cutting-edge pointwise cross-section to groupwise reaction rate: A primer

    NASA Astrophysics Data System (ADS)

    Sublet, Jean-Christophe; Fleming, Michael; Gilbert, Mark R.

    2017-09-01

    The nuclear research and development community has a history of using both integral and differential experiments to support accurate lattice-reactor, nuclear reactor criticality and shielding simulations, as well as verification and validation efforts of cross sections and emitted particle spectra. An important aspect to this type of analysis is the proper consideration of the contribution of the neutron spectrum in its entirety, with correct propagation of uncertainties and standard deviations derived from Monte Carlo simulations, to the local and total uncertainty in the simulated reactions rates (RRs), which usually only apply to one application at a time. This paper identifies deficiencies in the traditional treatment, and discusses correct handling of the RR uncertainty quantification and propagation, including details of the cross section components in the RR uncertainty estimates, which are verified for relevant applications. The methodology that rigorously captures the spectral shift and cross section contributions to the uncertainty in the RR are discussed with quantified examples that demonstrate the importance of the proper treatment of the spectrum profile and cross section contributions to the uncertainty in the RR and subsequent response functions. The recently developed inventory code FISPACT-II, when connected to the processed nuclear data libraries TENDL-2015, ENDF/B-VII.1, JENDL-4.0u or JEFF-3.2, forms an enhanced multi-physics platform providing a wide variety of advanced simulation methods for modelling activation, transmutation, burnup protocols and simulating radiation damage sources terms. The system has extended cutting-edge nuclear data forms, uncertainty quantification and propagation methods, which have been the subject of recent integral and differential, fission, fusion and accelerators validation efforts. The simulation system is used to accurately and predictively probe, understand and underpin a modern and sustainable understanding

  8. On the Cutting Edge Professional Development Program - An effective model built from years of experience

    NASA Astrophysics Data System (ADS)

    Bruckner, M. Z.; Macdonald, H.; Beane, R. J.; Manduca, C. A.; Mcconnell, D. A.; Mogk, D. W.; Tewksbury, B. J.; Wiese, K.; Wysession, M. E.; Iverson, E. A. R.; Fox, S.

    2015-12-01

    The On the Cutting Edge (CE) program offers a successful model for designing and convening professional development events. Information about the model is now available on the CE website. The program model has evolved from more than 12 years of experience, building with input from strong leaders and participants. CE offers face-to-face, virtual, and hybrid events, and features a rich website that supports these professional development events as well as a growing community with a shared interest in effective geoscience teaching. Data from national surveys, participant feedback, and self-report data indicate the program's success in improving undergraduate geoscience education. Successes are also demonstrated in classroom observations using RTOP, indicating a significant difference in teaching style among participants and non-participants. A suite of web pages, with a planning timeline, provides guidance to those interested in designing and convening face-to-face or virtual events based on the CE model. The pages suggest ways to develop robust event goals and evaluation tools, how to choose strong leaders and recruit diverse participants, advice for designing effective event programs that utilize participant expertise, websites, and web tools, and suggestions for effectively disseminating event results and producing useful products. The CE model has been successfully transferred to projects that vary in scale and discipline. Best practices from the CE model include (1) thinking of the workshop as shared enterprise among conveners and participants; (2) incorporating conveners and participants who bring diverse viewpoints and approaches; (3) promoting structured discussions that utilize participants' expertise; (4) emphasizing practical strategies to effect change; and (5) using the website as a platform to prepare for the workshop, share ideas, and problem-solve challenges. Learn more about how to utilize this model for your project at:serc.carleton.edu/NAGTWorkshops/workshops/convene

  9. Management of psoriatic arthritis: Early diagnosis, monitoring of disease severity and cutting edge therapies.

    PubMed

    Raychaudhuri, Siba P; Wilken, Reason; Sukhov, Andrea C; Raychaudhuri, Smriti K; Maverakis, Emanual

    2017-01-01

    Psoriatic arthritis (PsA) is a heterogeneous disease that can involve a variety of distinct anatomical sites including a patient's peripheral and axial joints, entheses, skin and nails. Appropriate management of PsA requires early diagnosis, monitoring of disease activity, and utilization of cutting edge therapies. To accomplish the former there are a variety of PsA-specific tools available to screen, diagnose, and assess patients. This review will outline the recently developed PsA screening tools, including the Toronto Psoriatic Arthritis Screening Questionnaire (TOPAS), the Psoriasis Epidemiology Screening Tool (PEST), the Psoriatic Arthritis Screening and Evaluation (PASE), and the Psoriasis and Arthritis Screening Questionnaire (PASQ). We will also review the Classification Criteria for Psoriatic Arthritis (CASPAR) and current PsA disease severity measures, such as the Disease Activity index for Psoriatic Arthritis (DAPSA), the Psoriatic Arthritis Joint Activity Index (PsAJAI) and the Composite Psoriatic Disease Activity Index (CPDAI). As is the case for PsA screening and assessment tools, there are also a variety of new therapies available for PsA. Historically, patients with PsA were treated with NSAIDS and traditional disease-modifying anti-rheumatic drugs (DMARDs). However, the ability of these medications to slow down the radiographic progression of joint disease has not been demonstrated. In contrast, anti-TNF agents, such as etanercept, infliximab, adalimumab, golimumab and certolizumab, are effective in this regard. Emerging PsA treatments include an oral phosphodiesterase 4 inhibitor, apremilast; a Janus kinase (JAK) inhibitor, tofacitinib; and several new biologics that target the IL-23/IL-17 pathway including secukinumab, brodalumab, ixekizumab, and ustekinumab. Herein we will review the mechanisms of action of these drugs, their results in clinical trials, and guidelines for administration. Lastly, treatment recommendations from the European League

  10. Optimal seamline detection for multiple image mosaicking via graph cuts

    NASA Astrophysics Data System (ADS)

    Li, Li; Yao, Jian; Lu, Xiaohu; Tu, Jinge; Shan, Jie

    2016-03-01

    While mosaicking images, especially captured from the scenes of large depth differences with respective to cameras at varying locations, the detection of seamlines within overlap regions is a key issue for creating seamless and pleasant image mosaics. In this paper, we propose a novel algorithm to efficiently detect optimal seamlines for mosaicking aerial images captured from different viewpoints and for mosaicking street-view panoramic images without a precisely common center in a graph cuts energy minimization framework. To effectively ensure that the seamlines are optimally detected in the laterally continuous regions with high image similarity and low object dislocation to magnificently conceal the parallax between images, we fuse the information of image color, gradient magnitude, and texture complexity into the data and smooth energy terms in graph cuts. Different from the traditional frame-to-frame optimization for sequentially detecting seamlines for mosaicking multiple images, our method applies a novel multi-frame joint optimization strategy to find seamlines within multi-overlapped images at one time. In addition, we propose simple but effective strategies to semi-automatically guide the seamlines by exploiting simple human-computer interaction strongly constraining the image regions that the seamlines will or won't pass through, which is often ignored by many existing seamline detection methods. Experimental results on a large set of aerial, oblique and street-view panoramic images show that the proposed method is capable of creating high-quality seamlines for multiple image mosaicking, while not crossing majority of visually obvious foreground objects and most of overlap regions with low image similarity to effectively conceal the image parallax at different extents.

  11. WWBT? What Would Ben Think about Killer Apps, Cutting Edges, and Tipping Points in the History of Weather and Climate?

    NASA Astrophysics Data System (ADS)

    Fleming, J. R.

    2006-12-01

    This paper examines the history of weather and climate since 1706 along three intertwined analytical axes: technology (killer apps), science (cutting edges), and social issues (tipping points). For example, Franklin's best-known killer app, the lightning rod, gains added significance when seen in light of his cutting edge contributions to the science of electricity, his lifelong promotion of useful knowledge, and the societal tipping point his work triggered in our relationship to the sky. Subsequently, other major tipping points and conceptual shifts followed the introduction of telegraphy, radio, television, digital computers, and rocketry into meteorology. Following an analysis of the career and contributions of Benjamin Franklin (1706-1790), the paper examines later historical moments and watersheds, not merely in retrospect, but from the perspective of leading participants at the time. It focuses on technologies of significant promise, especially those involving electro- magnetism, up to and including the dawn of the twenty-first century, and asks playfully, "What would Ben think?"

  12. Aircrew Performance Cutting-Edge Technology: Emerging Human Performance Enhancement Technology Vision in Support of Operational Military Aviation Strategy

    DTIC Science & Technology

    2003-09-01

    Osprey is the only aircraft designed from the ground-up specifically to counter the nuclear, biological, or chemical threat environment. The Osprey ...overpressure and filtration systems designed to protect troops carried by the Osprey from nuclear, Aircrew Performance Cutting-Edge Technology…21... designated a naval flight surgeon. This was followed by operational combat tours aboard the aircraft carriers USS Midway (CV-41), USS Independence (CV

  13. Incoherent optical processor for nondirectional edge enhancement of color images.

    PubMed

    Flores, Jorge L; Ayubi, Gastón A; Alonso, Julia R; Fernández, Ariel; Di Martino, J Matías; Ferrari, José A

    2011-12-01

    We present an optical method for nondirectional edge extraction/enhancement in color images. The method is based on the capability of twisted-nematic LCDs to traduce the image information in changes of the state of polarization of light, which allows us to generate simultaneously two replicas of the digital image displayed on the LCD: a true-color ("positive") image and a complementary-color ("negative") one. In our setup the imaging system consists of a lens plus a pupil mask formed with concentric apertures and orthogonal polarizers. This layout allows us to simultaneously image a well-focused positive replica (due to the circular aperture) superimposed to a slightly defocused negative one (due to the annular aperture). It is not difficult to demonstrate that this generates a nondirectional (Laplacian) edge enhancement. Unlike Fourier, our proposal works with incoherent illumination and does not require precise alignment, and thus, it could be a useful tool for edge extraction/enhancement in large images in real-time applications. Validation experiments are presented. © 2011 Optical Society of America

  14. Exemplar-based image inpainting using multiscale graph cuts.

    PubMed

    Liu, Yunqiang; Caselles, Vicent

    2013-05-01

    We present a novel formulation of exemplar-based inpainting as a global energy optimization problem, written in terms of the offset map. The proposed energy function combines a data attachment term that ensures the continuity of reconstruction at the boundary of the inpainting domain with a smoothness term that ensures a visually coherent reconstruction inside the hole. This formulation is adapted to obtain a global minimum using the graph cuts algorithm. To reduce the computational complexity, we propose an efficient multiscale graph cuts algorithm. To compensate the loss of information at low resolution levels, we use a feature representation computed at the original image resolution. This permits alleviation of the ambiguity induced by comparing only color information when the image is represented at low resolution levels. Our experiments show how well the proposed algorithm performs compared with other recent algorithms.

  15. mEdgeBoxes: objectness estimation for depth image

    NASA Astrophysics Data System (ADS)

    Fang, Zhiwen; Cao, Zhiguo; Xiao, Yang; Zhu, Lei; Lu, Hao

    2015-12-01

    Object detection is one of the most important researches in computer vision. Recently, category-independent objectness in RGB images has been a hot field for its generalization ability and efficiency as a pre-filtering procedure of the object detection. Many traditional applications have been transferred from the RGB images to the depth images since the economical depth sensors, such as Kinect, were popularized. The depth data represents the distance information. Because of the special characteristic, the methods of objectness evaluation in RGB images are often invalid in depth images. In this study, we propose mEdgeboxes to evaluate the objectness in depth image. Aside from detecting the edge from the raw depth information, we extract another edge map from the orientation information based on the normal vector. Two kinds of the edge map are integrated and are fed to Edgeboxes1 in order to produce the object proposals. The experimental results on two challenging datasets demonstrate that the detection rate of the proposed objectness estimation method can achieve over 90% with 1000 windows. It is worth noting that our approach generally outperforms the state-of-the-art methods on the detection rate.

  16. The cutting-edge training modalities and educational platforms for accredited surgical training: A systematic review

    PubMed Central

    Forgione, Antonello; Guraya, Salman Y.

    2017-01-01

    Background: Historically, operating room (OR) has always been considered as a stand-alone trusted platform for surgical education and training. However, concerns about financial constraints, quality control, and patient safety have urged the surgical educators to develop more cost-effective, surgical educational platforms that can be employed outside the OR. Furthermore, trained surgeons need to regularly update their surgical skills to keep abreast with the emerging surgical technologies. This research aimed to explore the value of currently available modern surgical tools that can be used outside the OR and also elaborates the existing laparoscopic surgical training programs in world-class centers across the globe with a view to formulate a blended and unified structured surgical training program. Materials and Methods: Several data sources were searched using MeSH terms “Laparoscopic surgery” and “Surgical training” and “Surgical curriculum” and “fundamentals of endoscopic surgery” and “fundamentals of laparoscopic surgery” and “Telementoring” and “Box trainer.” The eligibility criteria used in data extraction searched for original and review articles and by excluding the editorial articles, short communications, conference proceedings, personal view, and commentaries. Data synthesis and data analysis were done by reviewing the initially retrieved 211 articles. Irrelevant and duplicate and redundant articles were excluded from the study. Results: Finally, 12 articles were selected for this systematic review. Data results showed that a myriad of cutting-edge technical innovations have provided modern surgical training tools such as the simulation-based mechanical and virtual reality simulators, animal and cadaveric labs, telementoring, telerobotic-assisted surgery, and video games. Surgical simulators allow the trainees to acquire surgical skills in a tension-free environment without supervision or time constraints. Conclusion: The

  17. Teaching Service Learning in the Geosciences: An On the Cutting Edge Workshop Report

    NASA Astrophysics Data System (ADS)

    Bruckner, M. Z.; Laine, E. P.; Mogk, D. W.; O'Connell, S.; Kirk, K. B.

    2010-12-01

    Service learning is an instructional method that combines community service and academic instruction within the context of an established academic course. It is a particularly effective approach that uses active and experiential learning to develop the academic skills required of a course of study and to simultaneously address authentic community needs. Service learning projects can energize and motivate students by engaging a sense of civic responsibility by working in concert with community partners. The geosciences provide abundant opportunities to develop service learning projects on topics related to natural hazards, resources, land use, water quality, community planning, public policy, and education (K-12 and public outreach). To explore the opportunities of teaching service learning in the geosciences, the On the Cutting Edge program convened an online workshop in February 2010. The goals of the workshop were to: 1) introduce the principles and practices of effective service learning instructional activities; 2) provide examples of successful service learning projects and practical advice about "what works;" 3) provide participants with the opportunity to design, develop, and refine their own service learning courses or projects; 4) develop collections of supporting resources related to the pedagogy of service learning; and 5) support a community of scholars interested in continued work on service learning in the geoscience curriculum. The workshop consisted of a series of web-based synchronous and asynchronous sessions, including presentations from experienced practitioners of service learning, panel discussions, threaded discussions, and editable web pages used to develop new material for the website. Time was also provided for small group and individual work and for participants to peer-review each others' service learning projects and to revise their own activities based on reviewer comments. Insights from the workshop were integrated into new web pages

  18. Suboptimality of Nonlocal Means for Images with Sharp Edges

    DTIC Science & Technology

    2011-11-24

    Therefore Korostelev and Tsybakov proposed a framework to characterize the perfor - mance of image denoisers on edges [3]. Based on this framework, we...corresponds to f̂Wθ = IW(Tθ(W(y))). Donoho and Johnstone have proven that supf∈Hα(C) Rn(f, f̂ W ) = Ω(n−1) [4], [10]. Even though this rate is an improvement...the proximity of the image patch surrounding each noisy pixel with other patches in the image [14]. Define the δn-neighborhood distance dδn(yi,j, ym

  19. Cutting Edge: Resistance to Bacillus anthracis Infection Mediated by a Lethal Toxin Sensitive Allele of Nalp1b/Nlrp1b

    DTIC Science & Technology

    2010-01-01

    Nalp1b/Nlrp1b Lethal Toxin Sensitive Allele of Infection Mediated by aanthracis BacillusCutting Edge: Resistance to http://www.jimmunol.org/cgi/content...COVERED - 4. TITLE AND SUBTITLE Cutting edge: resistance to Bacillus anthracis infection mediated by a lethal toxin -sensitive allele of Nalp1b...Bacillus anthracis is associated with the production of lethal toxin (LT), which activates the murine Nalp1b/Nlrp1b inflammasome and induces caspase

  20. Improving Climate Science Education by Supporting Faculty: Climate Programs from On the Cutting Edge

    NASA Astrophysics Data System (ADS)

    Wiese, K.; Kirk, K. B.; Manduca, C. A.; Shellito, L. J.; Sztein, E.; Bruckner, M. Z.

    2011-12-01

    Students arrive in our classrooms with a wide range of viewpoints on climate change. Some carry misconceptions resulting from media portrayal of the subject; others have strong feelings about the policy of climate change that overshadow their understanding of the science; while some already grasp the basics of climate science and are thirsty for a more in-depth treatment. In any of these cases, the topic of climate change is likely to be of high interest to students and will challenge faculty to be well-versed in the science, the policy, and in effective pedagogic strategies. The On the Cutting Edge project continues its emphasis on climate science, climate change and energy resources with ongoing professional development events. An underlying theme of all of these events is to help faculty be more effective teachers by providing up-to-date science, examples of promising pedagogies and a forum to network with others who teach similar subjects. A monthly webinar and book club series about teaching climate and energy was offered throughout the 2010-2011 academic year. These one-hour events allowed faculty a convenient way to learn about science topics such as carbon capture and storage, nuclear energy, thermohaline circulation, alternative energy, or the energy-water nexus. Some of the webinars focused on pedagogic approaches, including teaching with climate models, dealing with misconceptions, or using local energy issues for a semester-long jigsaw project. Webinar participants reported that they could expand their teaching to include these topics, they increased their comfort level in presenting those subjects and answering student questions, and they learned where to turn for additional references. An online workshop, Teaching about Earth's Climate Using Data and Numerical Models, was held in October 2010. Participants learned about different types of models, the strategies for teaching with models and how to use online datasets. The workshop also provided

  1. Detecting Edges in Images by Use of Fuzzy Reasoning

    NASA Technical Reports Server (NTRS)

    Dominguez, Jesus A.; Klinko, Steve

    2003-01-01

    A method of processing digital image data to detect edges includes the use of fuzzy reasoning. The method is completely adaptive and does not require any advance knowledge of an image. During initial processing of image data at a low level of abstraction, the nature of the data is indeterminate. Fuzzy reasoning is used in the present method because it affords an ability to construct useful abstractions from approximate, incomplete, and otherwise imperfect sets of data. Humans are able to make some sense of even unfamiliar objects that have imperfect high-level representations. It appears that to perceive unfamiliar objects or to perceive familiar objects in imperfect images, humans apply heuristic algorithms to understand the images

  2. Image edge enhancement using Airy spiral phase filter.

    PubMed

    Zhou, Yi; Feng, Shaotong; Nie, Shouping; Ma, Jun; Yuan, Caojin

    2016-10-31

    The isotropic and anisotropic image edge enhancements by employing Airy spiral phase filters are proposed and demonstrated. The coherent spread functions of the image systems are derived from transmittance functions of their corresponding filters. In the isotropic method, the distributions of the coherent spread function with the radius of the main ring ρ0 and the scaled parameter w0 are numerically analyzed. It is found that the width of the main lobe determining the resolution decreases with the increased ρ0, and the amplitudes of the side lobes connecting with the contrast fluctuate with w0. Compared with the existing spiral phase filters, higher contrast and resolution can be achieved by adjusting the two parameters in the Airy spiral phase filter. Moreover, an off-axis Airy spiral phase filter by controlling the center position (ρ01) is designed and employed to implement anisotropic edge enhancement. In the experiments, two methods of image edge enhancement have been verified by using the amplitude-contrast and phase-contrast objects.

  3. High Speed Imaging of Edge Turbulence in NSTX

    SciTech Connect

    S.J. Zweben; R. Maqueda; D.P. Stotler; A. Keesee; J. Boedo; C. Bush; S. Kaye; B. LeBlanc; J. Lowrance; V. Mastrocola; R. Maingi; N. Nishino; G. Renda; D. Swain; J. Wilgen; the NSTX Team

    2003-03-01

    The two-dimensional radial versus poloidal structure and motion of edge turbulence in NSTX (National Spherical Torus Experiment) were measured by using high-speed imaging of the visible light emission from a localized neutral gas puff. Edge turbulence images are shown and analyzed for Ohmic, L-mode (low-confinement mode) and H-mode (high-confinement mode) plasma conditions. Typical edge turbulence poloidal correlation lengths as measured using this technique are = 4 {+-} 1 cm and autocorrelation times are 40 {+-} 20 {micro}sec in all three regimes. The relative fluctuation level is typically smaller in H-mode than in L-mode, and transitions from H- to L-mode and can occur remarkably quickly (=30 {micro}sec). The two-dimensional images often show localized regions of strong light emission which move both poloidally and radially through the observed region at a typical speed of =10{sup 5} cm/sec, and sometimes show spatially coherent modes.

  4. Superpixel Cut for Figure-Ground Image Segmentation

    NASA Astrophysics Data System (ADS)

    Yang, Michael Ying; Rosenhahn, Bodo

    2016-06-01

    Figure-ground image segmentation has been a challenging problem in computer vision. Apart from the difficulties in establishing an effective framework to divide the image pixels into meaningful groups, the notions of figure and ground often need to be properly defined by providing either user inputs or object models. In this paper, we propose a novel graph-based segmentation framework, called superpixel cut. The key idea is to formulate foreground segmentation as finding a subset of superpixels that partitions a graph over superpixels. The problem is formulated as Min-Cut. Therefore, we propose a novel cost function that simultaneously minimizes the inter-class similarity while maximizing the intra-class similarity. This cost function is optimized using parametric programming. After a small learning step, our approach is fully automatic and fully bottom-up, which requires no high-level knowledge such as shape priors and scene content. It recovers coherent components of images, providing a set of multiscale hypotheses for high-level reasoning. We evaluate our proposed framework by comparing it to other generic figure-ground segmentation approaches. Our method achieves improved performance on state-of-the-art benchmark databases.

  5. Cutting mechanics and manufacture of optics for imaging applications

    NASA Astrophysics Data System (ADS)

    Troutman, John Roberson

    Ultraprecision diamond machining enables physical realization of freeform surfaces of nearly arbitrary complexity through turning and milling processes. Achievable form accuracies make diamond machining a viable alternative to conventional techniques particularly for infrared and longer wavelength applications. This dissertation aims to further the knowledge base for manufacturing of infrared optics. Many infrared materials including germanium and chalcogenide glass (As40Se60, trade name IRG 26) are brittle, but under appropriate conditions, they can be machined in a ductile-dominated manner, resulting in a fracture-free and often optical quality surface. The cutting mechanics, surface condition, and subsurface integrity of these materials were studied to independently isolate effects due to cutting velocity, rake angle, and tool-workpiece interaction time. Experiments were performed under steady-state conditions using orthogonal, oblique, and round-nosed turning geometries, as well as under interrupted cutting conditions using flycutting and milling configurations. To overcome the limitations of conventional computer aided manufacturing packages, an analytical strategy for toolpath generation for slow tool servo machining operations was developed and verified in conjunction with an artifact-based approach for pre-process mapping and compensation of tool- and machine-based process error sources. The research findings were then used to select appropriate machining parameters and generate toolpaths for the manufacturing of several freeform optics including a chalcogenide glass Alvarez lens pair and the primary and tertiary mirrors of a compact imaging spectrometer.

  6. Accelerated edge-preserving image restoration without boundary artifacts.

    PubMed

    Matakos, Antonios; Ramani, Sathish; Fessler, Jeffrey A

    2013-05-01

    To reduce blur in noisy images, regularized image restoration methods have been proposed that use nonquadratic regularizers (like l1 regularization or total-variation) that suppress noise while preserving edges in the image. Most of these methods assume a circulant blur (periodic convolution with a blurring kernel) that can lead to wraparound artifacts along the boundaries of the image due to the implied periodicity of the circulant model. Using a noncirculant model could prevent these artifacts at the cost of increased computational complexity. In this paper, we propose to use a circulant blur model combined with a masking operator that prevents wraparound artifacts. The resulting model is noncirculant, so we propose an efficient algorithm using variable splitting and augmented Lagrangian (AL) strategies. Our variable splitting scheme, when combined with the AL framework and alternating minimization, leads to simple linear systems that can be solved noniteratively using fast Fourier transforms (FFTs), eliminating the need for more expensive conjugate gradient-type solvers. The proposed method can also efficiently tackle a variety of convex regularizers, including edge-preserving (e.g., total-variation) and sparsity promoting (e.g., l1-norm) regularizers. Simulation results show fast convergence of the proposed method, along with improved image quality at the boundaries where the circulant model is inaccurate.

  7. Accelerated Edge-Preserving Image Restoration Without Boundary Artifacts

    PubMed Central

    Matakos, Antonios; Ramani, Sathish; Fessler, Jeffrey A.

    2013-01-01

    To reduce blur in noisy images, regularized image restoration methods have been proposed that use non-quadratic regularizers (like l1 regularization or total-variation) that suppress noise while preserving edges in the image. Most of these methods assume a circulant blur (periodic convolution with a blurring kernel) that can lead to wraparound artifacts along the boundaries of the image due to the implied periodicity of the circulant model. Using a non-circulant model could prevent these artifacts at the cost of increased computational complexity. In this work we propose to use a circulant blur model combined with a masking operator that prevents wraparound artifacts. The resulting model is non-circulant, so we propose an efficient algorithm using variable splitting and augmented Lagrangian (AL) strategies. Our variable splitting scheme, when combined with the AL framework and alternating minimization, leads to simple linear systems that can be solved non-iteratively using FFTs, eliminating the need for more expensive CG-type solvers. The proposed method can also efficiently tackle a variety of convex regularizers including edge-preserving (e.g., total-variation) and sparsity promoting (e.g., l1 norm) regularizers. Simulation results show fast convergence of the proposed method, along with improved image quality at the boundaries where the circulant model is inaccurate. PMID:23372080

  8. Cutting Edge Technologies Presentation: An Overview of Developing Sensor Technology Directions and Possible Barriers to New Technology Implementation

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.

    2007-01-01

    The aerospace industry requires the development of a range of chemical sensor technologies for such applications as leak detection, emission monitoring, fuel leak detection, environmental monitoring, and fire detection. A range of chemical sensors are being developed based on micromachining and microfabrication technology to fabricate microsensors with minimal size, weight, and power consumption; and the use of nanomaterials and structures to develop sensors with improved stability combined with higher sensitivity, However, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. These technologies and technical approaches have direct relevance to breath monitoring for clinical applications. This presentation gives an overview of developing cutting-edge sensor technology and possible barriers to new technology implementation. This includes lessons learned from previous microsensor development, recent work in development of a breath monitoring system, and future directions in the implementation of cutting edge sensor technology.

  9. Edge detection - Image-plane versus digital processing

    NASA Technical Reports Server (NTRS)

    Huck, Friedrich O.; Fales, Carl L.; Park, Stephen K.; Triplett, Judith A.

    1987-01-01

    To optimize edge detection with the familiar Laplacian-of-Gaussian operator, it has become common to implement this operator with a large digital convolution mask followed by some interpolation of the processed data to determine the zero crossings that locate edges. It is generally recognized that this large mask causes substantial blurring of fine detail. It is shown that the spatial detail can be improved by a factor of about four with either the Wiener-Laplacian-of-Gaussian filter or an image-plane processor. The Wiener-Laplacian-of-Gaussian filter minimizes the image-gathering degradations if the scene statistics are at least approximately known and also serves as an interpolator to determine the desired zero crossings directly. The image-plane processor forms the Laplacian-of-Gaussian response by properly combining the optical design of the image-gathering system with a minimal three-by-three lateral-inhibitory processing mask. This approach, which is suggested by Marr's model of early processing in human vision, also reduces data processing by about two orders of magnitude and data transmission by up to an order of magnitude.

  10. An Interactive Procedure to Preserve the Desired Edges during the Image Processing of Noise Reduction

    NASA Astrophysics Data System (ADS)

    Hsu, Chih-Yu; Huang, Hsuan-Yu; Lee, Lin-Tsang

    2010-12-01

    The paper propose a new procedure including four stages in order to preserve the desired edges during the image processing of noise reduction. A denoised image can be obtained from a noisy image at the first stage of the procedure. At the second stage, an edge map can be obtained by the Canny edge detector to find the edges of the object contours. Manual modification of an edge map at the third stage is optional to capture all the desired edges of the object contours. At the final stage, a new method called Edge Preserved Inhomogeneous Diffusion Equation (EPIDE) is used to smooth the noisy images or the previously denoised image at the first stage for achieving the edge preservation. The Optical Character Recognition (OCR) results in the experiments show that the proposed procedure has the best recognition result because of the capability of edge preservation.

  11. A comparison of edge detecting algorithms in magnetic imaging

    NASA Astrophysics Data System (ADS)

    Ekinci, Yunus Levent

    2010-05-01

    process was performed in order to shift the anomalies laterally to be located over their respective sources. The results produced by the use of different edge detector algorithms were demonstrated with image maps and cross-sectional views for a comprehensive comparison. Keywords: Magnetic data, reduction to the pole, edge detectors, directional derivatives, 3D bodies

  12. Attracting "Cutting-Edge" Skills Through Reserve Component Participation

    DTIC Science & Technology

    2003-01-01

    once. As usual, though, we thank all these good people but absolve them all from any gremlins that might remain in this report. 1 Attracting “Cutting...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per...a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1 . REPORT DATE 2003 2

  13. Joint graph cut and relative fuzzy connectedness image segmentation algorithm.

    PubMed

    Ciesielski, Krzysztof Chris; Miranda, Paulo A V; Falcão, Alexandre X; Udupa, Jayaram K

    2013-12-01

    We introduce an image segmentation algorithm, called GC(sum)(max), which combines, in novel manner, the strengths of two popular algorithms: Relative Fuzzy Connectedness (RFC) and (standard) Graph Cut (GC). We show, both theoretically and experimentally, that GC(sum)(max) preserves robustness of RFC with respect to the seed choice (thus, avoiding "shrinking problem" of GC), while keeping GC's stronger control over the problem of "leaking though poorly defined boundary segments." The analysis of GC(sum)(max) is greatly facilitated by our recent theoretical results that RFC can be described within the framework of Generalized GC (GGC) segmentation algorithms. In our implementation of GC(sum)(max) we use, as a subroutine, a version of RFC algorithm (based on Image Forest Transform) that runs (provably) in linear time with respect to the image size. This results in GC(sum)(max) running in a time close to linear. Experimental comparison of GC(sum)(max) to GC, an iterative version of RFC (IRFC), and power watershed (PW), based on a variety medical and non-medical images, indicates superior accuracy performance of GC(sum)(max) over these other methods, resulting in a rank ordering of GC(sum)(max)>PW∼IRFC>GC.

  14. Edge turbulence measurements in NSTX by gas puff imaging

    NASA Astrophysics Data System (ADS)

    Maqueda, R. J.; Wurden, G. A.; Zweben, S.; Roquemore, L.; Kugel, H.; Johnson, D.; Kaye, S.; Sabbagh, S.; Maingi, R.

    2001-01-01

    Turbulent filaments in visible light emission corresponding mainly to density fluctuations at the edge have been observed in large aspect ratio tokamaks: TFTR, ASDEX, Alcator C-Mod, and DIII-D. This article reports on similar turbulent structures observed in the National Spherical Torus Experiment (NSTX) using a fast-framing, intensified, digital visible camera. These filaments were previously detected mainly in high recycling regions, such as at limiters or antennas, where the line emission from neutral atoms was modulated by the fluctuations in local plasma density. However, by introducing controlled edge gas puffs, i.e., gas puff imaging, we have increased the brightness and contrast in the fluctuation images and allowed the turbulent structure to be measured independently of the recycling. A set discrete fiber-optically coupled sight-lines also measured the frequency spectra of these light fluctuations with a 200 kHz bandwidth. Initial results in NSTX show that the turbulent filaments are well aligned with the magnetic field which can be up to 45° from the horizontal at the outer midplane of NSTX. The dominant wavelength perpendicular to the magnetic field is ˜7-11 cm, corresponding to a k⊥ ρs of ˜0.3 at an assumed Te=25 eV, and the frequency spectra has a typical broad shape characteristic of edge turbulence extending to about 100 kHz. By imaging a He gas puff along a magnetic field line the characteristic radial scalelength appears to be in the 3-5 cm range.

  15. A Novel Method for Edge Detection in Images Based on Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Baby Sherin, C.; Mredhula, L.

    2017-01-01

    Edges give important structural information about the images. Edge detection is a process of identifying and locating the edges in an image. Edges are the points where discontinuity of intensity occurs. It also represents the boundaries of objects in images. In this paper a new edge detection method based on Particle Swarm Optimization is discussed. The proposed method uses morphological operations and a thresholding technique to improve the result of edge detector. This algorithm performs better in images comparing to other traditional methods of edge detection. The performance of proposed method is compared with traditional edge detection methods such as Sobel, Prewitt, Laplacian of Gaussian and Canny with parameters Baddeley's Delta Metric. Statistical analysis is performed to evaluate accuracy of edge detection techniques.

  16. Edge Turbulence Imaging on NSTX and Alcator C-Mod

    SciTech Connect

    S.J. Zweben; R.A. Maqueda; J.L. Terry; B. Bai; C.J. Boswell; C.E. Bush; D. D'Ippolito; E.D. Fredrickson; M. Greenwald; K. Hallatschek; S. Kaye; B. LaBombard; R. Maingi; J. Myra; W.M. Nevins; B.N. Rogers; D.P. Stotler; J. Wilgen; and X.Q. Xu

    2002-07-10

    Edge turbulence images have been made using an ultra-high speed CCD camera on both NSTX and Alcator C-Mod. In both cases, the D-alpha or HeI (587.6 nm) line emission from localized deuterium or helium gas puffs was viewed along a local magnetic field line near the outer midplane. Fluctuations in this line emission reflect fluctuations in electron density and/or electron temperature through the atomic excitation rates, which can be modeled using the DEGAS-2 code. The 2-D structure of the measured turbulence can be compared with theoretical simulations based on 3-D fluid models.

  17. 2D Doppler backscattering using synthetic aperture microwave imaging of MAST edge plasmas

    NASA Astrophysics Data System (ADS)

    Thomas, D. A.; Brunner, K. J.; Freethy, S. J.; Huang, B. K.; Shevchenko, V. F.; Vann, R. G. L.

    2016-02-01

    Doppler backscattering (DBS) is already established as a powerful diagnostic; its extension to 2D enables imaging of turbulence characteristics from an extended region of the cut-off surface. The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D DBS experiments of MAST edge plasma. SAMI actively probes the plasma edge using a wide (±40° vertical and horizontal) and tuneable (10-34.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vivaldi PCB antennas. This allows the receiving array to be focused in any direction within the field of view simultaneously to an angular range of 6-24° FWHM at 10-34.5 GHz. This capability is unique to SAMI and is a novel way of conducting DBS experiments. In this paper the feasibility of conducting 2D DBS experiments is explored. Initial observations of phenomena previously measured by conventional DBS experiments are presented; such as momentum injection from neutral beams and an abrupt change in power and turbulence velocity coinciding with the onset of H-mode. In addition, being able to carry out 2D DBS imaging allows a measurement of magnetic pitch angle to be made; preliminary results are presented. Capabilities gained through steering a beam using a phased array and the limitations of this technique are discussed.

  18. 'Edge illumination' in X-ray Phase Contrast Imaging

    SciTech Connect

    Munro, Peter R. T.; Ignatyev, Konstantin; Diemoz, Paul C.; Szafraniec, Magdalena B.; Hagen, Charlotte K.; Millard, Thomas P.; Zapata, Cesar E.; Speller, Robert D.; Olivo, Alessandro

    2012-07-31

    In the late '90s, the concept of 'edge illumination' was developed at ELETTRA in Italy as an alternative method to increase the phase sensitivity of an imaging system. The main idea was to be able to reproduce the fine angular selection of 'analyzer' crystals without actually using a crystal, as this would allow employing the method with divergent and polychromatic (i.e. conventional) x-ray sources. It was observed that this could be achieved by illuminating only the edges of the detector pixels, and that the method's sensitivity could be progressively increased by illuminating smaller pixel fractions closer to its physical edge. A few years later the idea was adapted for use with a conventional source by means of two sets of x-ray masks ('coded aperture' masks), which enabled obtaining the same effect for each row (or column) of pixels of an area detector illuminated by a cone beam. This article reviews the method and presents recent examples of application.

  19. Edge-preserving image compression using adaptive lifting wavelet transform

    NASA Astrophysics Data System (ADS)

    Zhang, Libao; Qiu, Bingchang

    2015-07-01

    In this paper, a novel 2-D adaptive lifting wavelet transform is presented. The proposed algorithm is designed to further reduce the high-frequency energy of wavelet transform, improve the image compression efficiency and preserve the edge or texture of original images more effectively. In this paper, a new optional direction set, covering the surrounding integer pixels and sub-pixels, is designed. Hence, our algorithm adapts far better to the image orientation features in local image blocks. To obtain the computationally efficient and coding performance, the complete processes of 2-D adaptive lifting wavelet transform is introduced and implemented. Compared with the traditional lifting-based wavelet transform, the adaptive directional lifting and the direction-adaptive discrete wavelet transform, the new structure reduces the high-frequency wavelet coefficients more effectively, and the texture structures of the reconstructed images are more refined and clear than that of the other methods. The peak signal-to-noise ratio and the subjective quality of the reconstructed images are significantly improved.

  20. Iterative image reconstruction for CBCT using edge-preserving prior

    PubMed Central

    Wang, Jing; Li, Tianfang; Xing, Lei

    2009-01-01

    On-board cone-beam computed tomography (CBCT) is a new imaging technique for radiation therapy guidance, which provides volumetric information of a patient at treatment position. CBCT improves the setup accuracy and may be used for dose reconstruction. However, there is great concern that the repeated use of CBCT during a treatment course delivers too much of an extra dose to the patient. To reduce the CBCT dose, one needs to lower the total mAs of the x-ray tube current, which usually leads to reduced image quality. Our goal of this work is to develop an effective method that enables one to achieve a clinically acceptable CBCT image with as low as possible mAs without compromising quality. An iterative image reconstruction algorithm based on a penalized weighted least-squares (PWLS) principle was developed for this purpose. To preserve edges in the reconstructed images, we designed an anisotropic penalty term of a quadratic form. The algorithm was evaluated with a CT quality assurance phantom and an anthropomorphic head phantom. Compared with conventional isotropic penalty, the PWLS image reconstruction algorithm with anisotropic penalty shows better resolution preservation. PMID:19235393

  1. [Scanning electron microscopic investigations of cutting edge quality in lamellar keratotomy using the Wavelight femtosecond laser (FS-200) : What influence do spot distance and an additional tunnel have?

    PubMed

    Hammer, T; Höche, T; Heichel, J

    2017-07-24

    Femtosecond lasers (fs-lasers) are established cutting instruments for the creation of LASIK flaps. Previous studies often showed even rougher surfaces after application of fs-laser systems compared to lamellar keratotomy with mechanical microkeratomes. When cutting the cornea with fs-lasers, an intrastromal gas development occurs, which has a potentially negative influence on the cutting quality if the gas cannot be dissipated; therefore, manufacturers have chosen the way of gas assimilation in so-called pockets. The investigated system creates a tunnel which opens under the conjunctiva. The aim of this study was to investigate the effects of a tunnel as well as the influence of different spot distances on the quality of cut surfaces and edges. In this experimental study on freshly enucleated porcine eyes (n = 15), the following cuts were carried out with the FS-200 (Wavelight, Erlangen, Germany): 1. standard setting (spot and line separation 8 µm), 2. with tunnel for gas drainage, 3. without gas-conducting tunnel, 4. with increased spot spacing (spot and line separation 9 μm instead of 8 μm) and 5. with reduced spot spacing (spot and line separation 7 μm instead of 8 μm). Subsequently, scanning electron microscopy (FEI Quanta 650, Hillsboro, OR) of the cut edges and surfaces as well as the gas drain tunnel were performed. The evaluation was based on an established score. The current fs-laser system (200 Hz) is able to create smooth cutting surfaces and sharp edges. The changed density of laser pulses compared to the standard settings with a reduced or increased distance between the pulses, did not achieve any further improvement in the surface quality. The gas-conducting tunnel could be detected by scanning electron microscope. In the case of cutting without a tunnel, roughened surfaces and irregularities on the cutting edges were found. When the FS-200 fs-laser is used, LASIK cuts with very smooth cut surfaces and sharp cutting

  2. Image segmentation and edge enhancement with stabilized inverse diffusion equations.

    PubMed

    Pollak, I; Willsky, A S; Krim, H

    2000-01-01

    We introduce a family of first-order multidimensional ordinary differential equations (ODEs) with discontinuous right-hand sides and demonstrate their applicability in image processing. An equation belonging to this family is an inverse diffusion everywhere except at local extrema, where some stabilization is introduced. For this reason, we call these equations "stabilized inverse diffusion equations" (SIDEs). Existence and uniqueness of solutions, as well as stability, are proven for SIDEs. A SIDE in one spatial dimension may be interpreted as a limiting case of a semi-discretized Perona-Malik equation. In an experiment, SIDE's are shown to suppress noise while sharpening edges present in the input signal. Their application to image segmentation is also demonstrated.

  3. Hybrid edge and feature-based single-image superresolution

    NASA Astrophysics Data System (ADS)

    Islam, Mohammad Moinul; Islam, Mohammed Nazrul; Asari, Vijayan K.; Karim, Mohammad A.

    2016-07-01

    A neighborhood-dependent component feature learning method for regression analysis in single-image superresolution is presented. Given a low-resolution input, the method uses a directional Fourier phase feature component to adaptively learn the regression kernel based on local covariance to estimate the high-resolution image. The unique feature of the proposed method is that it uses image features to learn about the local covariance from geometric similarity between the low-resolution image and its high-resolution counterpart. For each patch in the neighborhood, we estimate four directional variances to adapt the interpolated pixels. This gives us edge information and Fourier phase gives features, which are combined to interpolate using kernel regression. In order to compare quantitatively with other state-of-the-art techniques, root-mean-square error and measure mean-square similarity are computed for the example images, and experimental results show that the proposed algorithm outperforms similar techniques available in the literature, especially at higher resolution scales.

  4. Soft, cutting edge of environmentalism: why and how the appropriate-technology notion is changing the movement

    SciTech Connect

    Morrison, D.E.

    1980-04-01

    The central theme of hard, or centralized, technology versus soft, or small and disperse, technology is traced through two stages of development that the author terms enthusiasm and realism. The overlap between the environmental movement and the soft-technology movement has given the appropriate-technology movement a broad base of ideological support. Soft-technology thinking in environmentalism is broadening its concerns. This trend tends to increase what to date has been environmentalism's rather marginal relevance and legitimacy in the original and still-central domain of the soft-technolgoy movement, namely the developing countries. The small is beautiful concept will force environmentalists to question their commitments to political ideologies as well as environmentalism when faced with achieving environmental reform in the context of achieving greater social equity through redistribution. According to the author, the soft-technology vision of transformation to a soft society is the cutting edge of thought in environmentalism. 45 footnotes, 1 table. (SAC)

  5. State-of-the-art MCT photodiodes for cutting-edge sensor applications by AIM

    NASA Astrophysics Data System (ADS)

    Figgemeier, H.; Hanna, S.; Eich, D.; Fries, P.; Mahlein, K.-M.; Wenisch, J.; Schirmacher, W.; Beetz, J.; Breiter, R.

    2017-02-01

    For about 30 years, AIM has been ranking among the leading global suppliers for high-performance MCT infrared detectors, with its portfolio spanning the photosensitivity cut-off range from the SWIR to the VLWIR and from 1st generation to 3rd generation FPA devices. To meet the market demands for SWaP-C- and IR-detectors with additional functionalities such as multicolor detection, AIM employs both LPE and MBE technology. From AIḾs line of highest-performance single color detectors fabricated by LPE, we will present our latest excellent results of 5.3 μm cut-off MWIR MCT detectors with 1024x768 pixels and a 10 μm pixel pitch. AIM's powerful low dark current LWIR and VLWIR p-on-n device technology on LPE-grown MCT has now been extended to the MWIR spectral range. A comparison of results from n-on-p and p-on-n MWIR MCT planar photodiode arrays is presented. Operating temperatures of 160 K and higher, in conjunction with low defect density and excellent thermal sensitivity (NETD) are attained. The results achieved for LPE MWIR are compared to MBE MWIR data. For both the cost-efficient production of MWIR single color MCT detectors, as well as 3rd generation multicolor MCT detectors, AIM makes use of MBE growth of MCT on large-area GaAs substrates. The now-available AIM MWIR single color MBE MCT detectors grown on GaAs are qualified, delivered, and have reached a maturity fully meeting customers' requirements. Representing AIM's multicolor detector development, latest test results on a 640x512 pixels with a 20 μm pitch design will be presented. The MWIR/MWIR diodes demonstrate high QE, very low color cross talk, and excellent NETD in conjunction with low defect densities.

  6. On-line fresh-cut lettuce quality measurement system using hyperspectral imaging

    USDA-ARS?s Scientific Manuscript database

    Lettuce, which is a main type of fresh-cut vegetable, has been used in various fresh-cut products. In this study, an online quality measurement system for detecting foreign substances on the fresh-cut lettuce was developed using hyperspectral reflectance imaging. The online detection system with a s...

  7. Incorporating Cutting Edge Scientific Results from the MARGINS-GeoPRISMS Program into the Undergraduate Curriculum: An Overview

    NASA Astrophysics Data System (ADS)

    Morgan, J. K.; Costa, A.; Goodliffe, A. M.; Marshall, J. S.; Iverson, E. A. R.

    2014-12-01

    The NSF-MARGINS Program funded a decade of research on continental margin processes, organized around four initiatives: (1) chemical cycling in subduction zones (SubFac), (2) seismogenic zone processes at subduction zones (SEIZE), (3) rupturing continental lithosphere (RCL), and (4) source to sink sediment cycling at continental margins (S2S). The outcomes of this research provided critical new observations and insights into fundamental geologic processes along continental margins, and associated geologic hazards and economic resources. The transition to the successor GeoPRISMS Program provided a unique opportunity to identify and synthesize the highlights of MARGINS research, and to disseminate this knowledge to educators and students who will carry out the next phase of cutting-edge scientific research. The NSF TUES Program funded a two-year project entitled: "Bringing NSF MARGINS Continental Margins Research into the Undergraduate Curriculum," enabling development of ~15 mini-lessons drawing on key MARGINS results and data sets. The mini-lesson development team consists of 18 educators and scientists, grouped by initiative, and guided by experts in MARGINS science and current educational research and practices. Webinars and virtual check-ins enable team interactions and exchange of ideas and experiences; in person workshops solidified pedagogical approaches and assessment strategies, as well as initiative frameworks for the mini-lessons. Field testing by team members and outside volunteers during AY 2013-14 identified challenges and opportunities, guiding mini-lesson revision and finalization. The MARGINS mini-lessons define coordinated, data-rich educational resources, easy to access and free to the public, ready to be incorporated into multiple common geoscience course frameworks, taking the first step toward building a community of practice of scientists and curriculum specialists with the shared goal of moving cutting-edge science into undergraduate

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

    PubMed

    Haq, Izhar; Anwar, Shahzad; Shah, Kamran; Khan, Muhammad Tahir; Shah, Shaukat Ali

    2015-01-01

    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.

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

    PubMed Central

    Haq, Izhar

    2015-01-01

    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. PMID:26407133

  10. Effect of cutting edge radius on surface roughness in diamond tool turning of transparent MgAl2O4 spinel ceramic

    NASA Astrophysics Data System (ADS)

    Yue, Xiaobin; Xu, Min; Du, Wenhao; Chu, Chong

    2017-09-01

    Transparent magnesium aluminate spinel (MgAl2O4) ceramic is one of an important optical materials. However, due to its pronounced hardness and brittleness, the optical machining of this material is very difficult. Diamond turning has advantages over the grinding process in flexibility and material removal rate. However, there is a lack of research that could support the use of diamond turning technology in the machining of MgAl2O4 spinel ceramic. Using brittle-ductile transition theory of brittle material machining, this work provides critical information that may help to realize ductile-regime turning of MgAl2O4 spinel ceramic. A characterization method of determination the cutting edge radius is introduced here. Suitable diamond tools were measured for sharpness and then chosen from a large number of candidate tools. The influence of rounded cutting edges on surface roughness of the MgAl2O4 spinel ceramic is also investigated. These results indicate that surface quality of MgAl2O4 spinel is relate to the radius of diamond tool's cutting edge, cutting speed, and feed rate. Sharp diamond tools (small radius of cutting edge) facilitated ductile-regime turning of MgAl2O4 spinel and shows great potential to reduce surface roughness and produce smoother final surface.

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

    PubMed

    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.

  12. Coastline Extraction from Aerial Images Based on Edge Detection

    NASA Astrophysics Data System (ADS)

    Paravolidakis, V.; Moirogiorgou, K.; Ragia, L.; Zervakis, M.; Synolakis, C.

    2016-06-01

    Nowadays coastline extraction and tracking of its changes become of high importance because of the climate change, global warming and rapid growth of human population. Coastal areas play a significant role for the economy of the entire region. In this paper we propose a new methodology for automatic extraction of the coastline using aerial images. A combination of a four step algorithm is used to extract the coastline in a robust and generalizable way. First, noise distortion is reduced in order to ameliorate the input data for the next processing steps. Then, the image is segmented into two regions, land and sea, through the application of a local threshold to create the binary image. The result is further processed by morphological operators with the aim that small objects are being eliminated and only the objects of interest are preserved. Finally, we perform edge detection and active contours fitting in order to extract and model the coastline. These algorithmic steps are illustrated through examples, which demonstrate the efficacy of the proposed methodology.

  13. National Intrepid Center of Excellence: Cutting Edge Interdisciplinary Care for TBI & PH

    DTIC Science & Technology

    2011-01-26

    interdisciplinary approach and calming milieu • Actigraphy and sleep diary/assessment early in the program allows for modification of sleep architecture ...Interdisciplinary Team interview (Day One) – Internist, Neuro/ Sleep , Psych, Neuropsych, Family Therapy, Chaplain • First Four days - initial...including Sleep Evaluation) ― Clinical Pharmacy Evaluation ― PM&R/OT/PT assessments 28 Comprehensive Neuro-Imaging • Brain Structure • Brain Lesions • Brain

  14. Cutting-edge technologies of medical radiography: tomosynthesis and double energy

    NASA Astrophysics Data System (ADS)

    Ustinov, A. O.; Dabagov, A. R.

    2017-02-01

    The tomosynthesis technology is on the fringe of linear and computer tomography, combining high information capacity and low exposure. Diagnosing pathology of chest organs at early stages is complicated due to overlapping views of the lung and bone tissues. By using different X-ray energy ranges tissues with different absorption factors are separated and their separate images are received. This technology ensures that pathology is revealed at the early stage during routine screening.

  15. Real-time oriented edge detection via difference of shifted image

    NASA Astrophysics Data System (ADS)

    Jeong, Kiseon; Jin, Moonyong; Hwang, Daegyu; Yoon, Sook; Park, Dong Sun

    2013-12-01

    We propose a novel oriented edge detection method called Difference of Shifted Image (DoSI) which has only subtractions between neighborhood pixels using padding-based shifting operation. Firstly, we can more quickly extract an oriented edge component in each direction from 8-neighborhoods using DoSI because there are no multiplications. Then, we can make a final edge map using all edge components by taking maximum value per each pixel. Moreover, we propose various types of oriented edge operators based on the Prewitt, Sobel and Laplacian. They are achieved by combinations of some oriented edge components obtained from DoSI. They have similar performance to existing edge operators based on convolution operations and also their procedures can be implemented in parallel. The experimental results show that the proposed edge detection methods requires less computation time than convolution-based methods and most of them are similar in edge description ability to the existing oriented edge operators.

  16. Remote Sensing Forage Quality for Browsing Herbivores: A Case Study of Cutting Edge Koala Conservation

    NASA Astrophysics Data System (ADS)

    Youngentob, K. N.; Au, J.; Held, A. A.; Foley, W. J.; Possingham, H. P.

    2014-12-01

    Managing landscapes for conservation requires a capacity to measure habitat quality. Although multiple factors are often responsible for the distribution and abundance of herbivores, spatial variations in the quality and quantity of plant forage are known to be important for many species. While we cannot see the chemical complexity of landscapes with our naked-eye, advances in imaging spectroscopy are making it possible to assess the quality of forage on a landscape-scale. Much research in this area has focused on the ability to estimate foliar nitrogen (N), because N is believed to be a limiting nutrient for many leaf eating animals. However, the total quantity of foliar N does not necessarily reflect the amount of N that can be utilized by herbivores. Available nitrogen (AvailN) is an invitro measure of forage quality that integrates the influence of tannins and fibre on the amount of foliar N that is available for digestion by herbivores. This may be a more meaningful measure of forage quality than total N for the many herbivorous species that are sensitive to the effects of tannins. Our previous research has demonstrated that it is possible to estimate this integrated measure of foliar nutritional quality at an individual tree crown level across multiple tree species using imaging spectroscopy (HyMap). Here we present a case study of how this remote sensing data is being used to help inform landscape management and conservation decisions for an iconic Australian species, the koala (Phascolarctos cinereus). We review the methods involved in developing maps of integrated measures of foliar nutritional quality for browsing herbivores with airborne imaging spectroscopy data and discuss their applications for wildlife management.

  17. Lung tumor segmentation in PET images using graph cuts.

    PubMed

    Ballangan, Cherry; Wang, Xiuying; Fulham, Michael; Eberl, Stefan; Feng, David Dagan

    2013-03-01

    The aim of segmentation of tumor regions in positron emission tomography (PET) is to provide more accurate measurements of tumor size and extension into adjacent structures, than is possible with visual assessment alone and hence improve patient management decisions. We propose a segmentation energy function for the graph cuts technique to improve lung tumor segmentation with PET. Our segmentation energy is based on an analysis of the tumor voxels in PET images combined with a standardized uptake value (SUV) cost function and a monotonic downhill SUV feature. The monotonic downhill feature avoids segmentation leakage into surrounding tissues with similar or higher PET tracer uptake than the tumor and the SUV cost function improves the boundary definition and also addresses situations where the lung tumor is heterogeneous. We evaluated the method in 42 clinical PET volumes from patients with non-small cell lung cancer (NSCLC). Our method improves segmentation and performs better than region growing approaches, the watershed technique, fuzzy-c-means, region-based active contour and tumor customized downhill.

  18. Edge Sharpness Assessment by Parametric Modeling: Application to Magnetic Resonance Imaging.

    PubMed

    Ahmad, R; Ding, Y; Simonetti, O P

    2015-05-01

    In biomedical imaging, edge sharpness is an important yet often overlooked image quality metric. In this work, a semi-automatic method to quantify edge sharpness in the presence of significant noise is presented with application to magnetic resonance imaging (MRI). The method is based on parametric modeling of image edges. First, an edge map is automatically generated and one or more edges-of-interest (EOI) are manually selected using graphical user interface. Multiple exclusion criteria are then enforced to eliminate edge pixels that are potentially not suitable for sharpness assessment. Second, at each pixel of the EOI, an image intensity profile is read along a small line segment that runs locally normal to the EOI. Third, the profiles corresponding to all EOI pixels are individually fitted with a sigmoid function characterized by four parameters, including one that represents edge sharpness. Last, the distribution of the sharpness parameter is used to quantify edge sharpness. For validation, the method is applied to simulated data as well as MRI data from both phantom imaging and cine imaging experiments. This method allows for fast, quantitative evaluation of edge sharpness even in images with poor signal-to-noise ratio. Although the utility of this method is demonstrated for MRI, it can be adapted for other medical imaging applications.

  19. Comparing object recognition from binary and bipolar edge images for visual prostheses.

    PubMed

    Jung, Jae-Hyun; Pu, Tian; Peli, Eli

    2016-11-01

    Visual prostheses require an effective representation method due to the limited display condition which has only 2 or 3 levels of grayscale in low resolution. Edges derived from abrupt luminance changes in images carry essential information for object recognition. Typical binary (black and white) edge images have been used to represent features to convey essential information. However, in scenes with a complex cluttered background, the recognition rate of the binary edge images by human observers is limited and additional information is required. The polarity of edges and cusps (black or white features on a gray background) carries important additional information; the polarity may provide shape from shading information missing in the binary edge image. This depth information may be restored by using bipolar edges. We compared object recognition rates from 16 binary edge images and bipolar edge images by 26 subjects to determine the possible impact of bipolar filtering in visual prostheses with 3 or more levels of grayscale. Recognition rates were higher with bipolar edge images and the improvement was significant in scenes with complex backgrounds. The results also suggest that erroneous shape from shading interpretation of bipolar edges resulting from pigment rather than boundaries of shape may confound the recognition.

  20. Comparing object recognition from binary and bipolar edge images for visual prostheses

    NASA Astrophysics Data System (ADS)

    Jung, Jae-Hyun; Pu, Tian; Peli, Eli

    2016-11-01

    Visual prostheses require an effective representation method due to the limited display condition which has only 2 or 3 levels of grayscale in low resolution. Edges derived from abrupt luminance changes in images carry essential information for object recognition. Typical binary (black and white) edge images have been used to represent features to convey essential information. However, in scenes with a complex cluttered background, the recognition rate of the binary edge images by human observers is limited and additional information is required. The polarity of edges and cusps (black or white features on a gray background) carries important additional information; the polarity may provide shape from shading information missing in the binary edge image. This depth information may be restored by using bipolar edges. We compared object recognition rates from 16 binary edge images and bipolar edge images by 26 subjects to determine the possible impact of bipolar filtering in visual prostheses with 3 or more levels of grayscale. Recognition rates were higher with bipolar edge images and the improvement was significant in scenes with complex backgrounds. The results also suggest that erroneous shape from shading interpretation of bipolar edges resulting from pigment rather than boundaries of shape may confound the recognition.

  1. On the Cutting Edge Workshop on Effective and Innovative Course Design: A Model for Designing Rigorous Introductory Courses

    NASA Astrophysics Data System (ADS)

    Tewksbury, B. J.; MacDonald, R. H.

    2004-12-01

    As part of a professional development program for faculty in the geosciences, the NSF-funded program On the Cutting Edge (http://serc.carleton.edu/NAGTWorkshops/) has developed and offered workshops for geoscience faculty that guide participants through a stimulating process designed to help faculty members articulate goals and design effective and innovative courses that both meet those goals and assess outcomes. Of approximately 150 faculty members who have participated in the workshops, more than 120 have designed introductory courses in topics ranging from physical geology to Earth systems to historical geology to oceanography. The method of course design taught through these workshops leads to the development of rigorous, student-centered introductory courses. Our method of course design begins, not with a list of content items, but with setting goals by answering the question, "What do I want my students to be able to do on their own when they are done with my class?", rather than the question, "What do I want my students to know in this subject?" Focusing on what faculty members want students to be able to do, rather than on what topics should be covered by the faculty member, promotes designing courses in which students are actively engaged in doing geoscience. This course design method emphasizes setting goals for students involving higher order thinking skills (e.g., analysis, synthesis, design, formulation, prediction, interpretation, evaluation), rather than lower order thinking skills (e.g., identification, description, recognition, classification). For example, the goal of having students be able to evaluate the geologic hazards in an unfamiliar region involves higher order thinking skills and engages the student in deeper analysis than simply asking students to recall and describe examples of geologic hazards covered in class. This goal also has imbedded in it many lower order thinking skills tasks (e.g., identification, description). Rigor comes in

  2. A Semi-Automatic Method for Image Analysis of Edge Dynamics in Living Cells.

    PubMed

    Huang, Lawrence; Helmke, Brian P

    2011-06-01

    Spatial asymmetry of actin edge ruffling contributes to the process of cell polarization and directional migration, but mechanisms by which external cues control actin polymerization near cell edges remain unclear. We designed a quantitative image analysis strategy to measure the spatiotemporal distribution of actin edge ruffling. Time-lapse images of endothelial cells (ECs) expressing mRFP-actin were segmented using an active contour method. In intensity line profiles oriented normal to the cell edge, peak detection identified the angular distribution of polymerized actin within 1 µm of the cell edge, which was localized to lamellipodia and edge ruffles. Edge features associated with filopodia and peripheral stress fibers were removed. Circular statistical analysis enabled detection of cell polarity, indicated by a unimodal distribution of edge ruffles. To demonstrate the approach, we detected a rapid, nondirectional increase in edge ruffling in serum-stimulated ECs and a change in constitutive ruffling orientation in quiescent, nonpolarized ECs. Error analysis using simulated test images demonstrate robustness of the method to variations in image noise levels, edge ruffle arc length, and edge intensity gradient. These quantitative measurements of edge ruffling dynamics enable investigation at the cellular length scale of the underlying molecular mechanisms regulating actin assembly and cell polarization.

  3. A Semi-Automatic Method for Image Analysis of Edge Dynamics in Living Cells

    PubMed Central

    Huang, Lawrence; Helmke, Brian P.

    2011-01-01

    Spatial asymmetry of actin edge ruffling contributes to the process of cell polarization and directional migration, but mechanisms by which external cues control actin polymerization near cell edges remain unclear. We designed a quantitative image analysis strategy to measure the spatiotemporal distribution of actin edge ruffling. Time-lapse images of endothelial cells (ECs) expressing mRFP-actin were segmented using an active contour method. In intensity line profiles oriented normal to the cell edge, peak detection identified the angular distribution of polymerized actin within 1 µm of the cell edge, which was localized to lamellipodia and edge ruffles. Edge features associated with filopodia and peripheral stress fibers were removed. Circular statistical analysis enabled detection of cell polarity, indicated by a unimodal distribution of edge ruffles. To demonstrate the approach, we detected a rapid, nondirectional increase in edge ruffling in serum-stimulated ECs and a change in constitutive ruffling orientation in quiescent, nonpolarized ECs. Error analysis using simulated test images demonstrate robustness of the method to variations in image noise levels, edge ruffle arc length, and edge intensity gradient. These quantitative measurements of edge ruffling dynamics enable investigation at the cellular length scale of the underlying molecular mechanisms regulating actin assembly and cell polarization. PMID:21643526

  4. Gattini 2010: cutting edge science at the bottom of the world

    NASA Astrophysics Data System (ADS)

    Moore, Anna M.; Ahmed, Sara; Ashley, Michael C. B.; Barreto, Max K.; Cui, Xiangqun; Delacroix, Alex; Feng, Longlong; Gong, Xuefei; Lawrence, Jon; Luong-van, Daniel M.; Martin, D. Christopher; Riddle, Reed; Rowley, Nicole; Shang, Zhaohui; Storey, John W. V.; Tothill, Nick F. H.; Travouillon, Tony; Wang, Lifan; Yang, Huigen; Yang, Ji; Zhou, Xu; Zhu, Zhengxi

    2010-07-01

    The high altitude Antarctic sites of Dome A and the South Pole offer intriguing locations for future large scale optical astronomical Observatories. The Gattini project was created to measure the optical sky brightness, large area cloud cover and aurora of the winter-time sky above such high altitude Antarctic sites. The Gattini- DomeA camera was installed on the PLATO instrument module as part of the Chinese-led traverse to the highest point on the Antarctic plateau in January 2008. This single automated wide field camera contains a suite of Bessel photometric filters (B, V, R) and a long-pass red filter for the detection and monitoring of OH emission. We have in hand one complete winter-time dataset (2009) from the camera that was recently returned in April 2010. The Gattini-South Pole UV camera is a wide-field optical camera that in 2011 will measure for the first time the UV properties of the winter-time sky above the South Pole dark sector. This unique dataset will consist of frequent images taken in both broadband U and B filters in addition to high resolution (R~5000) long slit spectroscopy over a narrow bandwidth of the central field. The camera is a proof of concept for the 2m-class Antarctic Cosmic Web Imager telescope, a dedicated experiment to directly detect and map the redshifted lyman alpha fluorescence or Cosmic Web emission we believe possible due to the unique geographical qualities of the site. We present the current status of both projects.

  5. Improving radiotherapy planning, delivery accuracy, and normal tissue sparing using cutting edge technologies

    PubMed Central

    Glide-Hurst, Carri K.

    2014-01-01

    In the United States, more than half of all new invasive cancers diagnosed are non-small cell lung cancer, with a significant number of these cases presenting at locally advanced stages, resulting in about one-third of all cancer deaths. While the advent of stereotactic ablative radiation therapy (SABR, also known as stereotactic body radiotherapy, or SBRT) for early-staged patients has improved local tumor control to >90%, survival results for locally advanced stage lung cancer remain grim. Significant challenges exist in lung cancer radiation therapy including tumor motion, accurate dose calculation in low density media, limiting dose to nearby organs at risk, and changing anatomy over the treatment course. However, many recent technological advancements have been introduced that can meet these challenges, including four-dimensional computed tomography (4DCT) and volumetric cone-beam computed tomography (CBCT) to enable more accurate target definition and precise tumor localization during radiation, respectively. In addition, advances in dose calculation algorithms have allowed for more accurate dosimetry in heterogeneous media, and intensity modulated and arc delivery techniques can help spare organs at risk. New delivery approaches, such as tumor tracking and gating, offer additional potential for further reducing target margins. Image-guided adaptive radiation therapy (IGART) introduces the potential for individualized plan adaptation based on imaging feedback, including bulky residual disease, tumor progression, and physiological changes that occur during the treatment course. This review provides an overview of the current state of the art technology for lung cancer volume definition, treatment planning, localization, and treatment plan adaptation. PMID:24688775

  6. a Novel Approach for Edge Detection of Low Contrast Satellite Images

    NASA Astrophysics Data System (ADS)

    Singh, K. K.; Bajpai, M. K.; Pandey, R. K.

    2015-03-01

    Discrimination between texture edges and geometrical edges is very difficult in low contrast images. Satellite images are low contrast images. It is important to extract the edges that are not clearly visible in case of Satellite images. The present work encompasses a new edge detection algorithm using newly constructed differentiator. Chebyshev polynomial based fractional order differentiator has been used for filtering operation on an image. High pass and Low pass filters are designed with the concept of Quadrature Mirror Filter (QMF). Pre-processing has been performed by using this filter. Sobel edge detection method has been applied on this pre-processed image. The algorithm has been tested with two different satellite images.

  7. Probabilistic Framework for the Characterization of Surfaces and Edges in Range Images, with Application to Edge Detection.

    PubMed

    Lejeune, Antoine; Verly, Jacques G; Droogenbroeck, Marc Van

    2017-08-29

    We develop a powerful probabilistic framework for the local characterization of surfaces and edges in range images, which is useful in many applications of computer vision, such as filtering, edge detection, feature extraction, and classification. We use the geometrical nature of the data to derive an analytic expression for the joint probability density function (pdf) for the random variables used to model the ranges of a set of pixels in a local neighborhood of an image. We decompose this joint pdf by considering independently the cases where two real world points corresponding to two neighboring pixels are locally on the same real world surface or not. In particular, we show that this joint pdf is linked to the Voigt pdf and not to the Gaussian pdf as it is assumed in some applications. We apply our framework to edge detection and develop a locally adaptive algorithm that is based on a probabilistic decision rule. We show in an objective evaluation that this new edge detector performs better than prior art edge detectors. This proves the benefits of the probabilistic characterization of the local neighborhood as a tool to improve applications that involve range images.

  8. MGDS: Free, on-line, cutting-edge tools to enable the democratisation of geoscience data

    NASA Astrophysics Data System (ADS)

    Goodwillie, A. M.; Ryan, W. B.; O'Hara, S.; Ferrini, V.; Arko, R. A.; Coplan, J.; Chan, S.; Carbotte, S. M.; Nitsche, F. O.; Bonczkowski, J.; Morton, J. J.; Weissel, R.; Leung, A.

    2010-12-01

    The availability of user-friendly, effective cyber-information resources for accessing and manipulating geoscience data has grown rapidly in recent years. Based at Lamont-Doherty Earth Observatory the MGDS group has developed a number of free tools that have wide application across the geosciences for both educators and researchers. A simple web page (http://www.marine-geo.org/) allows users to search for and download many types of data by key word, geographical region, or published citation. The popular Create Maps and Grids function and the downloadable Google Earth-compatible KML files appeal to a wide user base. MGDS MediaBank galleries (http://media.marine-geo.org/) enable users to view and download compelling images that are purposefully selected for their educational value from NSF-funded field programs. GeoMapApp (http://www.geomapapp.org), a free map-based interactive tool that works on any machine, is increasingly being adopted across a broad suite of users from middle school students to university researchers. GeoMapApp allows users to plot, manipulate and present data in an intuitive geographical reference frame. GeoMapApp offers a convenient way to explore the wide range of built-in data sets, to quickly generate maps and images that aid visualisation and, when importing their own gridded and tabular data sets, to access the same rich built-in functionality. A user guide, short multi-media tutorials, and webinar are available on-line. The regularly-updated Global Multi-Resolution Topography (GMRT) Synthesis is used as the default GeoMapApp base map and is an increasingly popular means to rapidly create location maps. Additionally, the layer manager offers a fast way to overlay and compare multiple data sets and is augmented by the ability to alter layer transparency so that underlying layers become visible. Examples of GeoMapApp built-in data sets include high-resolution land topography and ocean floor bathymetry derived from satellite and multi

  9. Range image segmentation using Zernike moment-based generalized edge detector

    NASA Technical Reports Server (NTRS)

    Ghosal, S.; Mehrotra, R.

    1992-01-01

    The authors proposed a novel Zernike moment-based generalized step edge detection method which can be used for segmenting range and intensity images. A generalized step edge detector is developed to identify different kinds of edges in range images. These edge maps are thinned and linked to provide final segmentation. A generalized edge is modeled in terms of five parameters: orientation, two slopes, one step jump at the location of the edge, and the background gray level. Two complex and two real Zernike moment-based masks are required to determine all these parameters of the edge model. Theoretical noise analysis is performed to show that these operators are quite noise tolerant. Experimental results are included to demonstrate edge-based segmentation technique.

  10. Range image segmentation using Zernike moment-based generalized edge detector

    NASA Technical Reports Server (NTRS)

    Ghosal, S.; Mehrotra, R.

    1992-01-01

    The authors proposed a novel Zernike moment-based generalized step edge detection method which can be used for segmenting range and intensity images. A generalized step edge detector is developed to identify different kinds of edges in range images. These edge maps are thinned and linked to provide final segmentation. A generalized edge is modeled in terms of five parameters: orientation, two slopes, one step jump at the location of the edge, and the background gray level. Two complex and two real Zernike moment-based masks are required to determine all these parameters of the edge model. Theoretical noise analysis is performed to show that these operators are quite noise tolerant. Experimental results are included to demonstrate edge-based segmentation technique.

  11. Advances in the optical imaging transition-edge sensory array

    NASA Astrophysics Data System (ADS)

    Bay, Thomas Joel

    Our universe contains many faint, compact objects that have an optical magnitude which can vary over the millisecond time scale, such as pulsars, low- mass X-ray binaries or cataclysmic variables. Maximally probing the detailed physics of these objects requires single photon detection with extremely high time and energy resolution. This regime is unaccessible to current conventional detectors. Transition-edge sensors are superconducting-based microcalorimeters that are able to measure the energy and time-of-arrival for single photons at high count rates. A constant voltage-bias stably maintains the TESs in the sharp transition region between the superconducting and normal states. The absorption of a photon will heat the detector, thereby raising its resistance. Using an inductor placed in series with the TES to couple it to a flux-locked SQUID readout, we can measure the resulting change in current, and hence, measure the energy and time-of-arrival of single photons. This thesis describes the first imaging TES detector designed to be sensitive to optical wave-length photons. Using thin-film tungsten TESs, we have demonstrated less than microsecond time resolution and energy resolution as low as 0.15 eV over the near-IR/optical/near-UV wave-length range with count rates of up to 30 kHz per pixel. To construct a working and useful detector array many challenges had to be overcome. The most significant challenge was to minimize unwanted infrared power loading on the array while maintaining an acceptable in-band throughput. I discuss the process of choosing a proper filter set and describe my contributions to the redesign of the 50 mK base stage in this context. Other topics discussed are the physics of transition-edge sensors, the fabrication of the tungsten TESs, the experimental apparatus and single and multiple pixel results.

  12. Simple method for modulation transfer function determination of digital imaging detectors from edge images

    NASA Astrophysics Data System (ADS)

    Buhr, Egbert; Guenther-Kohfahl, Susanne; Neitzel, Ulrich

    2003-06-01

    A simple variant of the edge method to determine the presampled modulation transfer function (MTF) of digital imaging detectors has been developed that produces sufficiently accurate MTF values for frequencies up to the Nyquist frequency limit of the detector with only a small amount of effort for alignment and computing. An oversampled edge spread function (ESF) is generated from the image of a slanted edge by rearranging the pixel data of N consecutive lines that correspond to a lateral shift of the edge of one pixel. The original data are used for the computational analysis without further data preprocessing. Since the number of lines leading to an edge shift of one pixel is generally a fractional number rather than an integer, a systematic error may be introduced in the MTF obtained. Simulations and theoretical investigations show that for all frequencies up to the Nyquist limit the relative error ΔMTF/MTF is below 1/(2N) and can thus be kept below a given threshold by a suitable choice of N. The method is especially useful for applications where the MTF is needed for frequencies up to the Nyquist frequency limit, like the determination of the detective quantum efficiency (DQE).

  13. Responses to dural puncture during institution of combined spinal-epidural analgesia: a comparison of 27 gauge pencil-point and 27 gauge cutting-edge needles.

    PubMed

    van den Berg, A A; Ghatge, S; Armendariz, G; Cornelius, D; Wang, S

    2011-03-01

    Pencil-point spinal needles are popular for combined spinal-epidural analgesia because they cause less dural puncture headache than cutting-edge spinal needles. However many parturients move, grimace, vocalise or experience paraesthesia or dysaesthesia during dural puncture when performing 'needle through needle' combined spinal-epidural analgesia. We compared dural puncture responses induced by pencil-point and cutting-edge needles (both 27 gauge). With institutional approval, 115 parturients presenting for elective caesarean section or labour analgesia were audited. After lignocaine infiltration, a Tuohy-type needle was inserted to loss of resistance to saline at a mid-lumbar interspace, and either a 27 gauge cutting-edge or 27 gauge pencil-point needle was inserted 'needle through needle' through the dura. During dural penetration, the occurrence of patient movement, grimacing or vocalisation was noted by a blinded observer, as was the patient's response to the question "Did you feel that?" asked by the anaesthetist. The audit comprised two similar groups of patients (caesarean section, n=30; labour analgesia, n=85). In both groups, grimacing and movement during thecal penetration occurred more frequently with pencil-point needles (P < 0.05 and P < 0.025, respectively). Pooled data analysis revealed that pencil-point and cutting-edge needles induced grimacing and movement in 17 (22%) and 2 (5%), spontaneous vocalisation in 4 (5%) and 1 (3%) and was perceived by 13 (17%) and 3 (8%) parturients (P < 0.025, P=NS, P=NS), respectively. Overall, 34 and 6 objective and subjective patient responses (P < 0.005) occurred when inserting these needles, respectively. Dural puncture by a 27 gauge pencil-point needle inserted 'needle through needle' when instituting combined spinal-epidural analgesia induces more iatrogenic responses than a 27 gauge cutting-edge needle.

  14. GeoMapApp, Virtual Ocean and Other Cutting-Edge Resources for Representing Geoscience Data

    NASA Astrophysics Data System (ADS)

    Goodwillie, A. M.; Ryan, W. B.; Coplan, J.; Carbotte, S. M.; Arko, R. A.; O'Hara, S.; Ferrini, V.; Bonczkowski, J.; Chan, S.; Weissel, R.; Morton, J. J.; de Leonardo, S.; Leung, A.

    2009-12-01

    bathymetry and high-resolution grids in the oceans, with highly-detailed land elevations to produce a seamless physiographic earth representation. The use of the GMRT base map provides a high visual impact. These tools are being developed by the Marine Geoscience Data System group, http://www.marine-geo.org/ . Other resources for enhancing the representation of data include a suite of KML files created to allow users to view a number of MGDS-related data sets using Google Earth™ (http://www.marine-geo.org/tools/kmls.php). MediaBank (http://media.marine-geo.org/), an on-line image and video gallery, contains many images - life forms around hydrothermal vents, for example - purposefully selected for use in education and communication with the general public. Examples will be shown of using these resources to effectively represent and analyse data.

  15. Understanding the Deep Earth: Slabs, Drips, Plumes and More - An On the Cutting Edge Workshop

    NASA Astrophysics Data System (ADS)

    Williams, M. L.; Mogk, D. W.; McDaris, J. R.

    2010-12-01

    Exciting new science is emerging from the study of the deep Earth using a variety of approaches: observational instrumentation (e.g. EarthScope’s USArray; IRIS), analysis of rocks (xenoliths, isotopic tracers), experimental methods (COMPRES facilities), and modeling (physical and computational, e.g. CIG program). New images and models of active faults, subducting plates, mantle drips, and rising plumes are spurring a new excitement about deep Earth processes and connections between Earth’s internal systems, the plate tectonic system, and the physiography of Earth’s surface. The integration of these lines of research presents unique opportunities and also challenges in geoscience education. How can we best teach about the architecture, composition, and processes of Earth where it is hidden from direct observation. How can we make deep Earth science relevant and meaningful to students across the geoscience curriculum? And how can we use the exciting new discoveries about Earth processes to attract new students into science? To explore the intersection of research and teaching about the deep Earth, a virtual workshop was convened in February 2010 for experts in deep Earth research and undergraduate geoscience education. The six-day workshop consisted of online plenary talks, large and small group discussions, asynchronous contributions using threaded listservs and web-based work spaces, as well as development and review of new classroom and laboratory activities. The workshop goals were to: 1) help participants stay current about data, tools, services, and research related to the deep earth, 2) address the "big science questions" related to deep earth (e.g. plumes, slabs, drips, post-perovskite, etc.) and explore exciting new scientific approaches, 3) to consider ways to effectively teach about "what can't be seen", at least not directly, and 4) develop and review classroom teaching activities for undergraduate education using these data, tools, services, and

  16. Picasso at the Nanoscale: The Art of Using Cutting-Edge Science to Understand Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Rose, Volker

    2015-03-01

    Scientists are using high-energy X-ray instruments to solve mysteries behind art masterpieces, including artwork by Picasso. Learn how Argonne National Laboratory is working with major art institutions, such as The Art Institute of Chicago and Smithsonian Institute, to unlock groundbreaking information about art, the artist, and our cultural heritage. A deep connection to our past and shared cultural heritage must be preserved to foster a balanced society where all humanity can thrive. This talk will describe analysis of paint materials used by Pablo Picasso at the nanoscale, as only possible at the brightest synchrotron sources. It will highlight how new imaging techniques can reveal the invisible, bringing to light underlying compositions of old masters' paintings. This in turn enables the writing of new art history and provides important material clues that can assist with attribution and authentication. We will explain how the use of new technology can lead to new discoveries, which, in turn, can change the public's and the specialists' perception of great works of art. In collaboration with scientists from The Art Institute of Chicago we have teamed up to study the chemical make up of zinc oxide pigments used in artworks by Pablo Picasso. We will show how highly focused X-ray beams with nanoscale spatial resolution and trace element sensitivity have helped to determine that Picasso has used conventional house paint in some of his paintings. Surprisingly, the study gives also new insights into the pigment material zinc oxide, which has also great potential in a variety of applications such as in spintronics or as transparent electrodes in solar panels. Work at the Advanced Photon Source and the Center for Nanoscale Materials was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DEAC02-06CH11357.

  17. Graph cut-based method for segmenting the left ventricle from MRI or echocardiographic images.

    PubMed

    Bernier, Michael; Jodoin, Pierre-Marc; Humbert, Olivier; Lalande, Alain

    2017-04-02

    In this paper, we present a fast and interactive graph cut method for 3D segmentation of the endocardial wall of the left ventricle (LV) adapted to work on two of the most widely used modalities: magnetic resonance imaging (MRI) and echocardiography. Our method accounts for the fundamentally different nature of both modalities: 3D echocardiographic images have a low contrast, a poor signal-to-noise ratio and frequent signal drop, while MR images are more detailed but also cluttered and contain highly anisotropic voxels. The main characteristic of our method is to work in a 3D Bezier coordinate system instead of the original Euclidean space. This comes with several advantages, including an implicit shape prior and a result guarantied not to have any holes in it. The proposed method is made of 4 steps. First, a 3D sampling of the LV cavity is made based on a Bezier coordinate system. This allows to warp the input 3D image to a Bezier space in which a plane corresponds to an anatomically plausible 3D Euclidean bullet shape. Second, a 3D graph is built and an energy term (which is based on the image gradient and a 3D probability map) is assigned to each edge of the graph, some of which being given an infinite energy to ensure the resulting 3D structure passes through key anatomical points. Third, a max-flow min-cut procedure is executed on the energy graph to delineate the endocardial surface. And fourth, the resulting surface is projected back to the Euclidean space where a post-processing convex hull algorithm is applied on every short axis slice to remove local concavities. Results obtained on two datasets reveal that our method takes between 2 and 5s to segment a 3D volume, it has better results overall than most state-of-the-art methods on the CETUS echocardiographic dataset and is statistically as good as a human operator on MR images.

  18. GeoMapApp and MARGINS Mini-Lessons: Cutting-Edge Resources for Modern Educators

    NASA Astrophysics Data System (ADS)

    Goodwillie, A. M.; Ryan, W. B.; Coplan, J.; Carbotte, S. M.; Arko, R. A.; O'Hara, S.; Ferrini, V.; Bonczkowski, J.; Chan, S.; Weissel, R.; Morton, J. J.; de Leonardo, S.; Leung, A.

    2009-12-01

    are available and contain examples of using these resources in MARGINS mini-lessons. MARGINS MediaBank (http://media.marine-geo.org/album/margins), an on-line gallery, uses web technology to serve a number of downloadable, searchable images from the NSF MARGINS project. Examples of MARGINS mini-lessons, GeoMapApp and MARGINS MediaBank will be shown.

  19. Ultrasound image edge detection based on a novel multiplicative gradient and Canny operator.

    PubMed

    Zheng, Yinfei; Zhou, Yali; Zhou, Hao; Gong, Xiaohong

    2015-07-01

    To achieve the fast and accurate segmentation of ultrasound image, a novel edge detection method for speckle noised ultrasound images was proposed, which was based on the traditional Canny and a novel multiplicative gradient operator. The proposed technique combines a new multiplicative gradient operator of non-Newtonian type with the traditional Canny operator to generate the initial edge map, which is subsequently optimized by the following edge tracing step. To verify the proposed method, we compared it with several other edge detection methods that had good robustness to noise, with experiments on the simulated and in vivo medical ultrasound image. Experimental results showed that the proposed algorithm has higher speed for real-time processing, and the edge detection accuracy could be 75% or more. Thus, the proposed method is very suitable for fast and accurate edge detection of medical ultrasound images. © The Author(s) 2014.

  20. Piezoelectric polymer gated OFET: Cutting-edge electro-mechanical transducer for organic MEMS-based sensors.

    PubMed

    Thuau, Damien; Abbas, Mamatimin; Wantz, Guillaume; Hirsch, Lionel; Dufour, Isabelle; Ayela, Cédric

    2016-12-07

    The growth of micro electro-mechanical system (MEMS) based sensors on the electronic market is forecast to be invigorated soon by the development of a new branch of MEMS-based sensors made of organic materials. Organic MEMS have the potential to revolutionize sensor products due to their light weight, low-cost and mechanical flexibility. However, their sensitivity and stability in comparison to inorganic MEMS-based sensors have been the major concerns. In the present work, an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET) has been demonstrated. Using poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer as active gate dielectric in the transistor mounted on a polymeric micro-cantilever, unique electro-mechanical properties were observed. Such an advanced scheme enables highly efficient integrated electro-mechanical transduction for physical and chemical sensing applications. Record relative sensitivity over 600 in the low strain regime (<0.3%) was demonstrated, which represents a key-step for the development of highly sensitive all organic MEMS-based sensors.

  1. Piezoelectric polymer gated OFET: Cutting-edge electro-mechanical transducer for organic MEMS-based sensors

    PubMed Central

    Thuau, Damien; Abbas, Mamatimin; Wantz, Guillaume; Hirsch, Lionel; Dufour, Isabelle; Ayela, Cédric

    2016-01-01

    The growth of micro electro-mechanical system (MEMS) based sensors on the electronic market is forecast to be invigorated soon by the development of a new branch of MEMS-based sensors made of organic materials. Organic MEMS have the potential to revolutionize sensor products due to their light weight, low-cost and mechanical flexibility. However, their sensitivity and stability in comparison to inorganic MEMS-based sensors have been the major concerns. In the present work, an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET) has been demonstrated. Using poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer as active gate dielectric in the transistor mounted on a polymeric micro-cantilever, unique electro-mechanical properties were observed. Such an advanced scheme enables highly efficient integrated electro-mechanical transduction for physical and chemical sensing applications. Record relative sensitivity over 600 in the low strain regime (<0.3%) was demonstrated, which represents a key-step for the development of highly sensitive all organic MEMS-based sensors. PMID:27924853

  2. Getting to low-cost algal biofuels: A monograph on conventional and cutting-edge harvesting and extraction technologies

    SciTech Connect

    Coons, James E.; Kalb, Daniel M.; Dale, Taraka; Marrone, Babetta L.

    2014-08-31

    Among the most formidable challenges to algal biofuels is the ability to harvest algae and extract intracellular lipids at low cost and with a positive energy balance. Here, we construct two paradigms that contrast energy requirements and costs of conventional and cutting-edge Harvesting and Extraction (H&E) technologies. By application of the parity criterion and the moderate condition reference state, an energy–cost paradigm is created that allows 1st stage harvesting technologies to be compared with easy reference to the National Alliance for Advanced Biofuels and Bioproducts (NAABB) target of $0.013/gallon of gasoline equivalent (GGE) and to the U.S. DOE's Bioenergy Technologies Office 2022 cost metrics. Drawing from the moderate condition reference state, a concentration-dependency paradigm is developed for extraction technologies, making easier comparison to the National Algal Biofuels Technology Roadmap (NABTR) target of less than 10% total energy. This monograph identifies cost-bearing factors for a variety of H&E technologies, describes a design basis for ultrasonic harvesters, and provides a framework to measure future technological advancements toward reducing H&E costs. Finally, we show that ultrasonic harvesters and extractors are uniquely capable of meeting both NAABB and NABTR targets. Ultrasonic technologies require further development and scale-up before they can achieve low-cost performance at industrially relevant scales. But, the advancement of this technology would greatly reduce H&E costs and accelerate the commercial viability of algae-based biofuels.

  3. Nicotinic Acetylcholine Receptors as Targets for Tobacco Cessation Therapeutics: Cutting-Edge Methodologies to Understand Receptor Assembly and Trafficking.

    PubMed

    Fox-Loe, Ashley M; Dwoskin, Linda P; Richards, Christopher I

    2016-01-01

    Tobacco dependence is a chronic relapsing disorder and nicotine, the primary alkaloid in tobacco, acts at nicotinic receptors to stimulate dopamine release in brain, which is responsible for the reinforcing properties of nicotine, leading to addiction. Although the majority of tobacco users express the desire to quit, only a small percentage of those attempting to quit are successful using the currently available pharmacotherapies. Nicotine upregulates the number of specific nicotinic receptors on the neuronal cell surface. An increase in receptor trafficking or preferential stoichiometric assembly of receptor subunits involves changes in assembly, endoplasmic reticulum export, vesicle transport, decreased degradation, desensitization, enhanced maturation of functional pentamers, and pharmacological chaperoning. Understanding these changes on a mechanistic level is important to the development of nicotinic receptors as drug targets. For this reason, cutting-edge methodologies are being developed and employed to pinpoint distinct changes in localization, assembly, export, vesicle trafficking, and stoichiometry in order to further understand the physiology of these receptors and to evaluate the action of novel therapeutics for smoking cessation.

  4. Piezoelectric polymer gated OFET: Cutting-edge electro-mechanical transducer for organic MEMS-based sensors

    NASA Astrophysics Data System (ADS)

    Thuau, Damien; Abbas, Mamatimin; Wantz, Guillaume; Hirsch, Lionel; Dufour, Isabelle; Ayela, Cédric

    2016-12-01

    The growth of micro electro-mechanical system (MEMS) based sensors on the electronic market is forecast to be invigorated soon by the development of a new branch of MEMS-based sensors made of organic materials. Organic MEMS have the potential to revolutionize sensor products due to their light weight, low-cost and mechanical flexibility. However, their sensitivity and stability in comparison to inorganic MEMS-based sensors have been the major concerns. In the present work, an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET) has been demonstrated. Using poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer as active gate dielectric in the transistor mounted on a polymeric micro-cantilever, unique electro-mechanical properties were observed. Such an advanced scheme enables highly efficient integrated electro-mechanical transduction for physical and chemical sensing applications. Record relative sensitivity over 600 in the low strain regime (<0.3%) was demonstrated, which represents a key-step for the development of highly sensitive all organic MEMS-based sensors.

  5. Iterative edge- and wavelet-based image registration of AVHRR and GOES satellite imagery

    NASA Technical Reports Server (NTRS)

    LeMoigne, Jacqueline; El-Saleous, Nazmi; Vermote, Eric

    1997-01-01

    Most automatic registration methods are either correlation-based, feature-based, or a combination of both. Examples of features which can be utilized for automatic image registration are edges, regions, corners, or wavelet-extracted features. In this paper, we describe two proposed approaches, based on edge or edge-like features, which are very appropriate to highlight regions of interest such as coastlines. The two iterative methods utilize the Normalized Cross-Correlation of edge and wavelet features and are applied to such problems as image-to-map registration, landmarking, and channel-to-channel co-registration, utilizing test data, AVHRR data, as well as GOES image data.

  6. Classification of visible and infrared hyperspectral images based on image segmentation and edge-preserving filtering

    NASA Astrophysics Data System (ADS)

    Cui, Binge; Ma, Xiudan; Xie, Xiaoyun; Ren, Guangbo; Ma, Yi

    2017-03-01

    The classification of hyperspectral images with a few labeled samples is a major challenge which is difficult to meet unless some spatial characteristics can be exploited. In this study, we proposed a novel spectral-spatial hyperspectral image classification method that exploited spatial autocorrelation of hyperspectral images. First, image segmentation is performed on the hyperspectral image to assign each pixel to a homogeneous region. Second, the visible and infrared bands of hyperspectral image are partitioned into multiple subsets of adjacent bands, and each subset is merged into one band. Recursive edge-preserving filtering is performed on each merged band which utilizes the spectral information of neighborhood pixels. Third, the resulting spectral and spatial feature band set is classified using the SVM classifier. Finally, bilateral filtering is performed to remove "salt-and-pepper" noise in the classification result. To preserve the spatial structure of hyperspectral image, edge-preserving filtering is applied independently before and after the classification process. Experimental results on different hyperspectral images prove that the proposed spectral-spatial classification approach is robust and offers more classification accuracy than state-of-the-art methods when the number of labeled samples is small.

  7. Locating edges and removing ringing artifacts in JPEG images by frequency-domain analysis.

    PubMed

    Popovici, Irina; Withers, W Douglas

    2007-05-01

    We present a method of locating edges in JPEG-coded images which operates in frequency space on the DCT coefficients. Applied to the quantized DCT coefficients of a block containing a straight edge, the method yields an equation for the edge in a fraction of the operations needed to dequantize and transform the coefficents to pixel values. As a sample application of this method, we present a technique for alleviating ringing artifacts in JPEG-coded images.

  8. Edge Detection Method Based on Neural Networks for COMS MI Images

    NASA Astrophysics Data System (ADS)

    Lee, Jin-Ho; Park, Eun-Bin; Woo, Sun-Hee

    2016-12-01

    Communication, Ocean And Meteorological Satellite (COMS) Meteorological Imager (MI) images are processed for radiometric and geometric correction from raw image data. When intermediate image data are matched and compared with reference landmark images in the geometrical correction process, various techniques for edge detection can be applied. It is essential to have a precise and correct edged image in this process, since its matching with the reference is directly related to the accuracy of the ground station output images. An edge detection method based on neural networks is applied for the ground processing of MI images for obtaining sharp edges in the correct positions. The simulation results are analyzed and characterized by comparing them with the results of conventional methods, such as Sobel and Canny filters.

  9. Visible imaging of edge fluctuations in the TFTR tokamak

    NASA Astrophysics Data System (ADS)

    Zweben, S. J.; Medley, S. S.

    1989-10-01

    Images of the visible light emission from the inner wall region of the TFTR tokamak [M. G. Bell et al., in Plasma Physics and Controlled Nuclear Fusion Research 1988, Proceedings of the 12th International Conference, Nice, France (IAEA, Vienna, in press)] have been made using a rapidly gated, intensified TV camera. Strong ``filamentation'' of the neutral deuterium Dα light is observed when the camera gating time is <100 μsec during neutral-beam-heated discharges. These turbulent filaments vary in position randomly versus time and have a poloidal wavelength of ≊3-5 cm, which is much shorter than their parallel wavelength of ≊100 cm. A second and new type of edge fluctuation phenomenon, which is called a ``merfe,'' is also described. Merfes are a regular poloidal pattern of toroidally symmetric, small-scale marfes that move away from the inner midplane during the current decay after neutral beam injection. Some tentative interpretations of these two phenomena are presented.

  10. [The frequency features and application of edge detection differential operators in medical image].

    PubMed

    Wu, Jian; Ding, Hui; Wang, Guangzhi; Ding, Haishu; Zhou, Yiyi

    2005-02-01

    Edge detection is an absolutely necessary step in medical image processing, and the use of differential operators to detect edge is one of the most common and effective methods. In this paper are analyzed the frequency features of the Roberts operator, Prewitt operator, Sobel operator and Laplacian operator from the viewpoint of frequency domain, and it is proposed that the frequency features of the differential operators should be considered when differential operator is being used and/or constructed. Because edge detection operator is sensitive to the edge type, the appropriate operator should be adopted in different edge type detection. Finally, the importance and necessity of selecting edge detection operator are validated in the MRI image edge processing.

  11. Riding the Cutting Edge

    ERIC Educational Resources Information Center

    Freit-Hammes, Lori

    2007-01-01

    When Western Wisconsin Technical College created the Health Benefits Improvement Team, they had no experience with the complexity and ever-changing demands of health care and its associated costs. See how they've embraced their mission and are changing the way business is done in their community.

  12. Cutting Edge EDU. @ USC.

    ERIC Educational Resources Information Center

    Mosher, Diana

    2000-01-01

    Discusses the principles and components of the University of Southern California's "smart building": the Marshall School of Business. The building's design, learning environment, use of high-tech learning tools, audio/video teleconferencing, and more than 1,100 data/power hookups, making it the most technologically advanced in the…

  13. Cutting Edge Cable Management.

    ERIC Educational Resources Information Center

    Peach, Roger

    1997-01-01

    Describes how one school district was able to efficiently install fragile telecommunication cabling throughout its high school and save thousands of dollars. Discusses solutions to some common cable-management problems. (GR)

  14. Cutting Edge Cable Management.

    ERIC Educational Resources Information Center

    Peach, Roger

    1997-01-01

    Describes how one school district was able to efficiently install fragile telecommunication cabling throughout its high school and save thousands of dollars. Discusses solutions to some common cable-management problems. (GR)

  15. Edge detection based on genetic algorithm and sobel operator in image

    NASA Astrophysics Data System (ADS)

    Tong, Xin; Ren, Aifeng; Zhang, Haifeng; Ruan, Hang; Luo, Ming

    2011-10-01

    Genetic algorithm (GA) is widely used as the optimization problems using techniques inspired by natural evolution. In this paper we present a new edge detection technique based on GA and sobel operator. The sobel edge detection built in DSP Builder is first used to determine the boundaries of objects within an image. Then the genetic algorithm using SOPC Builder proposes a new threshold algorithm for the image processing. Finally, the performance of the new edge detection technique-based the best threshold approaches in DSP Builder and Quartus II software is compared both qualitatively and quantitatively with the single sobel operator. The new edge detection technique is shown to perform very well in terms of robustness to noise, edge search capability and quality of the final edge image.

  16. Edge extraction of CT medical image based on wavelet transform algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Xiaojun; Li, Xinzheng; Lai, Weidong

    2011-06-01

    Since computer tomography (CT) image has been widely applied in clinic diagnostics, while for many applications the information directly provided by CT images is incomplete corrupted by noise or instrument defect, there has great demand to further the processing methods for improving the CT image quality. Among all image features, the edge profile of clinic focus has obvious influence on accurately translating CT image. In this paper, the wavelet filtering algorithm based on modulus maximum method is put forward to extract and enhance the CT image edges. Edges in the brain lobe CT image can be outlined after wavelet transform, during which the wavelet assigned as the first order derivative of Gauss function. Further manipulation through maximum threshold checking to the modulus have been attenuated the pseudo-edges. After segmented with the original CT image, the edge structure has been distinctly enhanced, and high contrast is achieved between the brain lobe microstructure and the artificially established edges. The proposed algorithm is more efficient than the common first order differential operator, for the latter it even deteriorates the edge features. The algorithm proposed in this article can be integrated in medical image analyzing software to obtain higher accuracy for symptom interpretation.

  17. Fluorescence hyperspectral imaging technique for the foreign substance detection on fresh-cut lettuce

    USDA-ARS?s Scientific Manuscript database

    Nondestructive methods based on fluorescence hyperspectral imaging (HSI) techniques were developed in order to detect worms on fresh-cut lettuce. The optimal wavebands for detecting worms on fresh-cut lettuce were investigated using the one-way ANOVA analysis and correlation analysis. The worm detec...

  18. Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I. J.; George, G. N.; Gupta, M.; Chapman, D.

    2008-09-01

    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.

  19. Simulation of router action on a lathe to test the cutting tool performance in edge-trimming of graphite/epoxy composite

    NASA Astrophysics Data System (ADS)

    Ramulu, M.; Rogers, E.

    1994-04-01

    The predominant machining application with graphite/epoxy composite materials in aerospace industry is peripheral trimming. The computer numerically controlled (CNC) high speed routers required to do edge trimming work are generally scheduled for production work in industry and are not available for extensive cutter testing. Therefore, an experimental method of simulating the conditions of periphery trim using a lathe is developed in this paper. The validity of the test technique will be demonstrated by conducting carbide tool wear tests under dry cutting conditions. The experimental results will be analyzed to characterize the wear behavior of carbide cutting tools in machining the composite materials.

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

    NASA Astrophysics Data System (ADS)

    Kawalec-Latała, Ewa

    2014-03-01

    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.

  1. Getting Started in Academic Careers: On the Cutting Edge Resources for Graduate Students, Postdoctoral Fellows, and Early Career Faculty

    NASA Astrophysics Data System (ADS)

    MacDonald, R.; Ormand, C.; Manduca, C. A.; Wright-Dunbar, R.; Allen-King, R.

    2007-12-01

    The professional development program,'On the Cutting Edge', offers on-line resources and annual multi-day workshops for graduate students and post-doctoral fellows interested in pursuing academic careers. Pre- workshop surveys reveal that early career faculty, post-docs, and graduate students have many questions about teaching (e.g., what are effective teaching strategies, how to design a course, how to prepare a syllabus, how to teach large courses), research (e.g., initiate and fund future research, set up and manage a lab, obtain equipment), and career management (e.g., understand tenure requirements, balance all it all). The graduate students and post-docs also have questions about jobs and the job search process. Their questions show a lack of familiarity with the nature of academic positions at different kinds of educational institutions (two-year colleges, primarily undergraduate institutions, and research universities). In particular, they are uncertain about what educational setting will best fit their values and career goals and how teaching loads and research expectations vary by institution. Common questions related to the job search process include where to find job listings (the most common question in recent years), when to start the job search process, how to stand out as an applicant, and how to prepare for interviews. Both groups have questions about how to develop new skills: how to develop, plan and prepare a new course (without it taking all of their time), how to expand beyond their PhD (or postdoc) research projects, how to develop a research plan, and where to apply for funding. These are important topics for advisors to discuss with all of their students and postdocs who are planning on careers in academia. On the Cutting Edge offers workshops and web resources to help current and future faculty navigate these critical stages of their careers. The four-day workshop for Early Career Geoscience Faculty: Teaching, Research, and Managing Your

  2. Cytoplasm segmentation on cervical cell images using graph cut-based approach.

    PubMed

    Zhang, Ling; Kong, Hui; Chin, Chien Ting; Wang, Tianfu; Chen, Siping

    2014-01-01

    This paper proposes a method to segment the cytoplasm in cervical cell images using graph cut-based algorithm. First, the A* channel in CIE LAB color space is extracted for contrast enhancement. Then, in order to effectively extract cytoplasm boundaries when image histograms present non-bimodal distribution, Otsu multiple thresholding is performed on the contrast enhanced image to generate initial segments, based on which the segments are refined by the multi-way graph cut method. We use 21 cervical cell images with non-ideal imaging condition to evaluate cytoplasm segmentation performance. The proposed method achieved a 93% accuracy which outperformed state-of-the-art works.

  3. Enhancing your Teaching and Developing New Leadership: Impact of the On the Cutting Edge Professional Development Program

    NASA Astrophysics Data System (ADS)

    Iverson, E.; Manduca, C.; McLaughlin, J. A.; MacDonald, H.

    2005-12-01

    The goal of the On the Cutting Edge faculty professional development program is to improve geoscience education by keeping geoscience faculty up to date with changes in content and teaching methods. Six workshops each year focus on emerging themes in pedagogy and content; teaching upper division courses in the major; course design; teaching, research and career management for early career faculty; and preparing for an academic career. To date over 500 faculty, post-docs, and graduate students have participated in one or more workshops. To determine the impact of the workshops and associated websites, evaluators interviewed 54 of the program's participants and conducted an online survey for which nearly 50% of all participants responded. The interviews and related survey indicate four major areas of impact: 1) a change in participants' focus from "what do I teach" to "what are they learning"; 2) introduction of new teaching methods into courses; 3) increased emphasis in course content on emerging geoscience research (emerging theme workshop participants) and connections between geoscience and humans; 4) increased confidence, new skills, and new connections that enable participants to expand their sphere of influence and take on leadership positions in a wide range of venues (e.g. campus, regional, national, international) and in new professional areas (e.g. geoscience education, teacher preparation). Both the workshops and the associated websites are viewed as important resources in enabling these changes. The websites have played an important role in allowing participants to share what they have learned with colleagues both on campus and beyond. In sum, most participants believe that the workshops are of high value and can articulate important changes in their professional work that resulted from their participation.

  4. Getting to low-cost algal biofuels: A monograph on conventional and cutting-edge harvesting and extraction technologies

    DOE PAGES

    Coons, James E.; Kalb, Daniel M.; Dale, Taraka; ...

    2014-08-31

    Among the most formidable challenges to algal biofuels is the ability to harvest algae and extract intracellular lipids at low cost and with a positive energy balance. Here, we construct two paradigms that contrast energy requirements and costs of conventional and cutting-edge Harvesting and Extraction (H&E) technologies. By application of the parity criterion and the moderate condition reference state, an energy–cost paradigm is created that allows 1st stage harvesting technologies to be compared with easy reference to the National Alliance for Advanced Biofuels and Bioproducts (NAABB) target of $0.013/gallon of gasoline equivalent (GGE) and to the U.S. DOE's Bioenergy Technologiesmore » Office 2022 cost metrics. Drawing from the moderate condition reference state, a concentration-dependency paradigm is developed for extraction technologies, making easier comparison to the National Algal Biofuels Technology Roadmap (NABTR) target of less than 10% total energy. This monograph identifies cost-bearing factors for a variety of H&E technologies, describes a design basis for ultrasonic harvesters, and provides a framework to measure future technological advancements toward reducing H&E costs. Finally, we show that ultrasonic harvesters and extractors are uniquely capable of meeting both NAABB and NABTR targets. Ultrasonic technologies require further development and scale-up before they can achieve low-cost performance at industrially relevant scales. But, the advancement of this technology would greatly reduce H&E costs and accelerate the commercial viability of algae-based biofuels.« less

  5. An energy-based model for the image edge-histogram specification problem.

    PubMed

    Mignotte, Max

    2012-01-01

    In this correspondence, we present an original energy-based model that achieves the edge-histogram specification of a real input image and thus extends the exact specification method of the image luminance (or gray level) distribution recently proposed by Coltuc et al. Our edge-histogram specification approach is stated as an optimization problem in which each edge of a real input image will tend iteratively toward some specified gradient magnitude values given by a target edge distribution (or a normalized edge histogram possibly estimated from a target image). To this end, a hybrid optimization scheme combining a global and deterministic conjugate-gradient-based procedure and a local stochastic search using the Metropolis criterion is proposed herein to find a reliable solution to our energy-based model. Experimental results are presented, and several applications follow from this procedure.

  6. Edge structure preserving 3D image denoising by local surface approximation.

    PubMed

    Qiu, Peihua; Mukherjee, Partha Sarathi

    2012-08-01

    In various applications, including magnetic resonance imaging (MRI) and functional MRI (fMRI), 3D images are becoming increasingly popular. To improve the reliability of subsequent image analyses, 3D image denoising is often a necessary preprocessing step, which is the focus of the current paper. In the literature, most existing image denoising procedures are for 2D images. Their direct extensions to 3D cases generally cannot handle 3D images efficiently because the structure of a typical 3D image is substantially more complicated than that of a typical 2D image. For instance, edge locations are surfaces in 3D cases which would be much more challenging to handle compared to edge curves in 2D cases. We propose a novel 3D image denoising procedure in this paper, based on local approximation of the edge surfaces using a set of surface templates. An important property of this method is that it can preserve edges and major edge structures (e.g., intersections of two edge surfaces and pointed corners). Numerical studies show that it works well in various applications.

  7. Region quad-tree decomposition based edge detection for medical images.

    PubMed

    Dua, Sumeet; Kandiraju, Naveen; Chowriappa, Pradeep

    2010-05-28

    Edge detection in medical images has generated significant interest in the medical informatics community, especially in recent years. With the advent of imaging technology in biomedical and clinical domains, the growth in medical digital images has exceeded our capacity to analyze and store them for efficient representation and retrieval, especially for data mining applications. Medical decision support applications frequently demand the ability to identify and locate sharp discontinuities in an image for feature extraction and interpretation of image content, which can then be exploited for decision support analysis. However, due to the inherent high dimensional nature of the image content and the presence of ill-defined edges, edge detection using classical procedures is difficult, if not impossible, for sensitive and specific medical informatics-based discovery. In this paper, we propose a new edge detection technique based on the regional recursive hierarchical decomposition using quadtree and post-filtration of edges using a finite difference operator. We show that in medical images of common origin, focal and/or penumbral blurred edges can be characterized by an estimable intensity gradient. This gradient can further be used for dismissing false alarms. A detailed validation and comparison with related works on diabetic retinopathy images and CT scan images show that the proposed approach is efficient and accurate.

  8. Swarm Intelligence for Optimizing Hybridized Smoothing Filter in Image Edge Enhancement

    NASA Astrophysics Data System (ADS)

    Rao, B. Tirumala; Dehuri, S.; Dileep, M.; Vindhya, A.

    In this modern era, image transmission and processing plays a major role. It would be impossible to retrieve information from satellite and medical images without the help of image processing techniques. Edge enhancement is an image processing step that enhances the edge contrast of an image or video in an attempt to improve its acutance. Edges are the representations of the discontinuities of image intensity functions. For processing these discontinuities in an image, a good edge enhancement technique is essential. The proposed work uses a new idea for edge enhancement using hybridized smoothening filters and we introduce a promising technique of obtaining best hybrid filter using swarm algorithms (Artificial Bee Colony (ABC), Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO)) to search for an optimal sequence of filters from among a set of rather simple, representative image processing filters. This paper deals with the analysis of the swarm intelligence techniques through the combination of hybrid filters generated by these algorithms for image edge enhancement.

  9. Real-time image edge enhancement with a spiral phase filter and graphic processing unit.

    PubMed

    Zhong, Zhi; Gao, Pengjun; Shan, Mingguang; Wang, Ying; Zhang, Yabin

    2014-07-01

    Isotropic image edge enhancement with high contrast can be achieved using a spiral phase filter (SPF) in a 4f optical system. However, real-time application of edge enhancement with SPF has generally been limited due to the requirement of coherent light or complex phase-shifting operation. In this paper, we demonstrate a real-time image edge enhancement method using a SPF and a graphic processing unit (GPU). By implementing the process of virtual spiral phase filtering on GPU, we are able to speed up the whole procedure by more than 8.3× with respect to CPU processing, and ultimately achieve video rate for megapixel images. In particular, our implementation can achieve higher speedup for more multiple images. These developments are increasing the potential for image edge enhancement of moving objects.

  10. Lung vessel segmentation in CT images using graph-cuts

    NASA Astrophysics Data System (ADS)

    Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

    2016-03-01

    Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are based on analyzing the eigenvalues of the Hessian matrix are popular for pulmonary vessel enhancement. However, due to their low response at vessel bifurcations and vessel boundaries, extracting lung vessels by thresholding the vesselness is not sufficiently accurate. Some methods turn to graph-cuts for more accurate segmentation, as it incorporates neighbourhood information. In this work, we propose a new graph-cuts cost function combining appearance and shape, where CT intensity represents appearance and vesselness from a Hessian-based filter represents shape. Due to the amount of voxels in high resolution CT scans, the memory requirement and time consumption for building a graph structure is very high. In order to make the graph representation computationally tractable, those voxels that are considered clearly background are removed from the graph nodes, using a threshold on the vesselness map. The graph structure is then established based on the remaining voxel nodes, source/sink nodes and the neighbourhood relationship of the remaining voxels. Vessels are segmented by minimizing the energy cost function with the graph-cuts optimization framework. We optimized the parameters used in the graph-cuts cost function and evaluated the proposed method with two manually labeled sub-volumes. For independent evaluation, we used 20 CT scans of the VESSEL12 challenge. The evaluation results of the sub-volume data show that the proposed method produced a more accurate vessel segmentation compared to the previous methods, with F1 score 0.76 and 0.69. In the VESSEL12 data-set, our method obtained a competitive performance with an area under the ROC curve of 0.975, especially among the binary submissions.

  11. Laser cutting of graphite anodes for automotive lithium-ion secondary batteries: investigations in the edge geometry and heat-affected zone

    NASA Astrophysics Data System (ADS)

    Schmieder, Benjamin

    2012-03-01

    To serve the high need of lithium-ion secondary batteries of the automobile industry in the next ten years it is necessary to establish highly reliable, fast and non abrasive machining processes. In previous works [1] it was shown that high cutting speeds with several meters per second are achievable. For this, mainly high power single mode fibre lasers with up to several kilo watts were used. Since lithium-ion batteries are very fragile electro chemical systems, the cutting speed is not the only thing important. To guarantee a high cycling stability and a long calendrical life time the edge quality and the heat affected zone (HAZ) are equally important. Therefore, this paper tries to establish an analytical model for the geometry of the cutting edge based on the ablation thresholds of the different materials. It also deals with the composition of the HAZ in dependence of the pulse length, generated by laser remote cutting with pulsed fibre laser. The characterisation of the HAZ was done by optical microscopy, SEM, EDX and Raman microscopy.

  12. X-ray imaging characterization of active edge silicon pixel sensors

    NASA Astrophysics Data System (ADS)

    Ponchut, C.; Ruat, M.; Kalliopuska, J.

    2014-05-01

    The aim of this work was the experimental characterization of edge effects in active-edge silicon pixel sensors, in the frame of X-ray pixel detectors developments for synchrotron experiments. We produced a set of active edge pixel sensors with 300 to 500 μm thickness, edge widths ranging from 100 μm to 150 μm, and n or p pixel contact types. The sensors with 256 × 256 pixels and 55 × 55 μm2 pixel pitch were then bump-bonded to Timepix readout chips for X-ray imaging measurements. The reduced edge widths makes the edge pixels more sensitive to the electrical field distribution at the sensor boundaries. We characterized this effect by mapping the spatial response of the sensor edges with a finely focused X-ray synchrotron beam. One of the samples showed a distortion-free response on all four edges, whereas others showed variable degrees of distortions extending at maximum to 300 micron from the sensor edge. An application of active edge pixel sensors to coherent diffraction imaging with synchrotron beams is described.

  13. Development of the iterative edge detection method applied on blurred satellite images: state of the art

    NASA Astrophysics Data System (ADS)

    Rahimzadegan, Majid; Sadeghi, Behnam

    2016-07-01

    This paper aims to implement an iterative fuzzy edge detection (IFED) method on blurred satellite images. Some degradation effects such as atmospheric effects, clouds and their shadows, atmospheric aerosols, and fog remarkably decline the quality satellite images. Hence, some processes such as enhancement and edge detection in satellite images are challenging. One group of methods that can deal with these effects is fuzzy logic methods. Therefore, IFED method was applied in this work on the subimages of the Ikonos, Landsat 7, and SPOT 5 satellite images, contaminated by aforementioned effects. Such as most FED methods, IFED has two components: enhancement and edge detection. In this context, a six-step iterative method, using the if-then-else mechanism, was implemented on the images to perform fuzzy enhancement, and subsequently, edge detection was done. To evaluate the merit of the enhancement and select the best number of iterations, edge gray-value rate criterion was applied. The peak signal-to-noise ratio (PSNR) is applied for the quantitative evaluation of the IFED method. The results of IFED, in comparison with some prior edge detection methods, showed higher PSNR values and a high performance in the edge detection of the earth features in the blurred satellite images.

  14. Lithographic imaging-driven pattern edge placement errors at 10nm node

    NASA Astrophysics Data System (ADS)

    Tyminski, Jacek K.; Renwick, Stephen P.; Palmer, Shane R.; Sakamoto, Julia A.; Slonaker, Steven D.

    2016-03-01

    Demand for ever increasing level of microelectronics integration continues unabated, driving the reduction of the integrated circuit critical dimensions, and escalating requirements for image overlay and pattern dimension control. The challenges to meet these demands are compounded by requirement that pattern edge placement errors be at single nanometer levels. Layout design together with the patterning tools performance play key roles in determining location of the pattern edges at different device layers. However, complexities of the layout design often lead to stringent tradeoffs for viable optical proximity correction and imaging strategy solutions. As a result, in addition to scanner overlay performance, pattern imaging plays a key role in the pattern edge placement. The imaging contributes to edge displacement by impacting the image dimensions and by shifting the images relative to their target locations. In this report we discuss various aspects of advanced image control at 10 nm integrated circuit design rules. We analyze the impact of pattern design and scanner performance on pattern edges. We present an example of complex, three step litho-etch patterning involving immersion scanners. We draw conclusion on edge placement control when complex images interact with wafer topography.

  15. On the Cutting Edge: Face-to-Face and Virtual Professional Development for Current and Future Geoscience Faculty

    NASA Astrophysics Data System (ADS)

    Macdonald, H.; Manduca, C. A.; Mogk, D. W.; Tewksbury, B. J.; Iverson, E. A.; Kirk, K. B.; Beane, R. J.; McConnell, D.; Wiese, K.; Wysession, M. E.

    2011-12-01

    On the Cutting Edge, a comprehensive, discipline-wide professional development program for current and future geoscience faculty, aims to develop a geoscience professoriate committed to high-quality instruction based on currency in scientific knowledge, good pedagogic practice, and research on learning. Our program provides an integrated workshop series and online teaching resources. Since 2002, we have offered more than 80 face-to-face workshops, virtual workshops and webinars, and hybrid events. Participants come from two-year colleges and four-year colleges and universities. The workshop series is designed to address the needs of faculty in all career stages at the full spectrum of institutions and covering the breadth of the geoscience curriculum. We select timely and compelling topics and create opportunities of interest to faculty. We offer workshops on course design, new geoscience research and pedagogical topics, core geoscience curriculum topics, and introductory courses as well as workshops for early career faculty and for future faculty. Our workshops are designed to model good teaching practice. We set workshop goals that guide workshop planning and evaluation. Workshops are interactive, emphasize participant learning, provide opportunities for participants to interact and share experience/knowledge, provide good resources, give participants time to reflect and to develop action plans, and help transform their ideas about teaching. We emphasize the importance of adaptation in the context of their specific situations. For virtual workshops and webinars we use icebreakers and other structured interactions to build a comfortable workshop community; promote interaction through features on webinar software, chat-aided question and answer, small-group synchronous interactions, and/or discussion boards; plan detailed schedules for workshop events; use asynchronous discussions and recordings of synchronous events given that participants are busy with their

  16. On the Cutting Edge Professional Development Program: Workshop and Web Resources for Current and Future Geoscience Faculty

    NASA Astrophysics Data System (ADS)

    MacDonald, R.; Manduca, C. A.; Mogk, D. W.; Tewksbury, B. J.

    2004-12-01

    Recognizing that many college and university faculty receive little formal training in teaching, are largely unaware of advances in research on teaching and learning, and face a variety of challenges in advancing in academic careers, the National Science Foundation-funded program On the Cutting Edge provides professional development for current and future faculty in the geosciences at various stages in their careers. The program includes a series of six multi-day workshops, sessions and one-day workshops at professional meetings, and a website with information about workshop opportunities and a variety of resources that bring workshop content to faculty (http://serc.carleton.edu/NAGTWorkshops). The program helps faculty improve their teaching and their job satisfaction by providing resources on instructional methods, geoscience content, and strategies for career planning. Workshop and website resources address innovative and effective practices in teaching, course design, delivery of instructional materials, and career planning, as well as approaches for teaching particular topics and strategies for starting and maintaining a research program in various institutional settings. Each year, special workshops for graduate students and post-doctoral fellows interested in academic careers and for early career faculty complement offerings on course design and emerging topics that are open to the full geoscience community. These special workshops include sessions on topics such as dual careers, gender issues, family-work balance, interviewing and negotiating strategies. The workshops serve as opportunities for networking and community building, with participants building connections with other participants as well as workshop leaders. Workshop participants reflect the full range of institutional diversity as well as ethnic and racial diversity beyond that of the geoscience faculty workforce. More than 40 percent of the faculty participants are female. Of the faculty

  17. Simultaneous x-ray fluorescence and K-edge CT imaging with photon-counting detectors

    NASA Astrophysics Data System (ADS)

    Li, Liang; Li, Ruizhe; Zhang, Siyuan; Chen, Zhiqiang

    2016-10-01

    Rapid development of the X-ray phonon-counting detection technology brings tremendous research and application opportunities. In addition to improvements in conventional X-ray imaging performance such as radiation dose utilization and beam hardening correction, photon-counting detectors allows significantly more efficient X-ray fluorescence (XRF) and K-edge imaging, and promises a great potential of X-ray functional, cellular and molecular imaging. XRF is the characteristic emission of secondary X-ray photons from a material excited by initial X-rays. The phenomenon is widely used for chemical and elemental analysis. K-edge imaging identifies a material based on its chemically-specific absorption discontinuity over X-ray photon energy. In this paper, we try to combine XRF and K-edge signals from the contrast agents (e.g., iodine, gadolinium, gold nanoparticles) to simultaneously realize XFCT and K-edge CT imaging for superior image performance. As a prerequisite for this dual-modality imaging, the accurate energy calibration of multi-energy-bin photon-counting detectors is critically important. With the measured XRF data of different materials, we characterize the energy response function of a CZT detector for energy calibration and spectrum reconstruction, which can effectively improve the energy resolution and decrease the inconsistence of the photon counting detectors. Then, a simultaneous K-edge and X-ray fluorescence CT imaging (SKYFI) experimental setup is designed which includes a cone-beam X-ray tube, two separate photon counting detector arrays, a pin-hole collimator and a rotation stage. With a phantom containing gold nanoparticles the two types of XFCT and K-edge CT datasets are collected simultaneously. Then, XFCT and K-edge CT images are synergistically reconstructed in a same framework. Simulation results are presented and quantitative analyzed and compared with the separate XFCT and K-edge CT results.

  18. Optimal Gabor filter-based edge detection of high spatial resolution remotely sensed images

    NASA Astrophysics Data System (ADS)

    Zhao, Haohao; Xiao, Pengfeng; Feng, Xuezhi

    2017-01-01

    Edge extraction from high spatial resolution (HSR) remotely sensed images is one of the essential tasks for image segmentation and object identification. We present an optimal Gabor-based edge detection method which mainly focuses on selecting optimal parameters, including central frequency and spectrum scale, for Gabor filter. The central frequency is automatically optimized by phase randomization and the human visual system-based structure similarity index. Next, the optimal spectrum scale is determined based on two-dimensional power spectrum density. The edge detection method is comprehensively discussed in the analysis of parameter sensitivity, overall performance, and comparative tests with several widely used methods. Qualitative and quantitative experimental studies, performed on six test images with various spatial resolution, show that the proposed method provides a promising solution to edge detection from HSR remotely sensed images.

  19. Preprocessing of Edge of Light images: towards a quantitative evaluation

    NASA Astrophysics Data System (ADS)

    Liu, Zheng; Forsyth, David S.; Marincak, Anton

    2003-08-01

    A computer vision inspection system, named Edge of Light TM (EOL), was invented and developed at the Institute for Aerospace Research of the National Research Council Canada. One application of interest is the detection and quantitative measurement of "pillowing" caused by corrosion in the faying surfaces of aircraft fuselage joints. To quantify the hidden corrosion, one approach is to relate the average corrosion of a region to the peak-to-peak amplitude between two diagonally adjacent rivet centers. This raises the requirement for automatically locating the rivet centers. The first step to achieve this is the rivet edge detection. In this study, gradient-based edge detection, local energy based feature extraction, and an adaptive threshold method were employed to identify the edge of rivets, which facilitated the first step in the EOL quantification procedure. Furthermore, the brightness profile is processed by the derivative operation, which locates the pillowing along the scanning direction. The derivative curves present an estimation of the inspected surface.

  20. Color Image Segmentation Based on Different Color Space Models Using Automatic GrabCut

    PubMed Central

    Ebied, Hala Mousher; Hussein, Ashraf Saad; Tolba, Mohamed Fahmy

    2014-01-01

    This paper presents a comparative study using different color spaces to evaluate the performance of color image segmentation using the automatic GrabCut technique. GrabCut is considered as one of the semiautomatic image segmentation techniques, since it requires user interaction for the initialization of the segmentation process. The automation of the GrabCut technique is proposed as a modification of the original semiautomatic one in order to eliminate the user interaction. The automatic GrabCut utilizes the unsupervised Orchard and Bouman clustering technique for the initialization phase. Comparisons with the original GrabCut show the efficiency of the proposed automatic technique in terms of segmentation, quality, and accuracy. As no explicit color space is recommended for every segmentation problem, automatic GrabCut is applied with RGB, HSV, CMY, XYZ, and YUV color spaces. The comparative study and experimental results using different color images show that RGB color space is the best color space representation for the set of the images used. PMID:25254226

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

    NASA Astrophysics Data System (ADS)

    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

  2. Liver Segmentation Based on Snakes Model and Improved GrowCut Algorithm in Abdominal CT Image

    PubMed Central

    He, Baochun; Ma, Zhiyuan; Zong, Mao; Zhou, Xiangrong; Fujita, Hiroshi

    2013-01-01

    A novel method based on Snakes Model and GrowCut algorithm is proposed to segment liver region in abdominal CT images. First, according to the traditional GrowCut method, a pretreatment process using K-means algorithm is conducted to reduce the running time. Then, the segmentation result of our improved GrowCut approach is used as an initial contour for the future precise segmentation based on Snakes model. At last, several experiments are carried out to demonstrate the performance of our proposed approach and some comparisons are conducted between the traditional GrowCut algorithm. Experimental results show that the improved approach not only has a better robustness and precision but also is more efficient than the traditional GrowCut method. PMID:24066017

  3. Image-Data Compression Using Edge-Optimizing Algorithm for WFA Inference.

    ERIC Educational Resources Information Center

    Culik, Karel II; Kari, Jarkko

    1994-01-01

    Presents an inference algorithm that produces a weighted finite automata (WFA), in particular, the grayness functions of graytone images. Image-data compression results based on the new inference algorithm produces a WFA with a relatively small number of edges. Image-data compression results alone and in combination with wavelets are discussed.…

  4. Image-Data Compression Using Edge-Optimizing Algorithm for WFA Inference.

    ERIC Educational Resources Information Center

    Culik, Karel II; Kari, Jarkko

    1994-01-01

    Presents an inference algorithm that produces a weighted finite automata (WFA), in particular, the grayness functions of graytone images. Image-data compression results based on the new inference algorithm produces a WFA with a relatively small number of edges. Image-data compression results alone and in combination with wavelets are discussed.…

  5. The optimization of edge and line detectors for forest image analysis

    Treesearch

    Zhiling Long; Joseph Picone; Victor A. Rudis

    2000-01-01

    Automated image analysis for forestry applications is becoming increasingly important with the rapid evolution of satellite and land-based remote imaging industries. Features derived from line information play a very important role in analyses of such images. Many edge and line detection algorithms have been proposed but few, if any, comprehensive studies exist that...

  6. Device for cutting protrusions

    DOEpatents

    Bzorgi, Fariborz M [Knoxville, TN

    2011-07-05

    An apparatus for clipping a protrusion of material is provided. The protrusion may, for example, be a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab protruding from a substrate surface of assembled components. The apparatus typically includes a cleaver having a cleaving edge and a cutting blade having a cutting edge. Generally, a mounting structure configured to confine the cleaver and the cutting blade and permit a range of relative movement between the cleaving edge and the cutting edge is provided. Also typically included is a power device coupled to the cutting blade. The power device is configured to move the cutting edge toward the cleaving edge. In some embodiments the power device is activated by a momentary switch. A retraction device is also generally provided, where the retraction device is configured to move the cutting edge away from the cleaving edge.

  7. Genetic parameters of Visual Image Analysis primal cut carcass traits of commercial prime beef slaughter animals.

    PubMed

    Moore, K L; Mrode, R; Coffey, M P

    2017-03-15

    Visual Image analysis (VIA) of carcass traits provides the opportunity to estimate carcass primal cut yields on large numbers of slaughter animals. This allows carcases to be better differentiated and farmers to be paid based on the primal cut yields. It also creates more accurate genetic selection due to high volumes of data which enables breeders to breed cattle that better meet the abattoir specifications and market requirements. In order to implement genetic evaluations for VIA primal cut yields, genetic parameters must first be estimated and that was the aim of this study. Slaughter records from the UK prime slaughter population for VIA carcass traits was available from two processing plants. After edits, there were 17 765 VIA carcass records for six primal cut traits, carcass weight as well as the EUROP conformation and fat class grades. Heritability estimates after traits were adjusted for age ranged from 0.32 (0.03) for EUROP fat to 0.46 (0.03) for VIA Topside primal cut yield. Adjusting the VIA primal cut yields for carcass weight reduced the heritability estimates, with estimates of primal cut yields ranging from 0.23 (0.03) for Fillet to 0.29 (0.03) for Knuckle. Genetic correlations between VIA primal cut yields adjusted for carcass weight were very strong, ranging from 0.40 (0.06) between Fillet and Striploin to 0.92 (0.02) between Topside and Silverside. EUROP conformation was also positively correlated with the VIA primal cuts with genetic correlation estimates ranging from 0.59 to 0.84, whereas EUROP fat was estimated to have moderate negative correlations with primal cut yields, estimates ranged from -0.11 to -0.46. Based on these genetic parameter estimates, genetic evaluation of VIA primal cut yields can be undertaken to allow the UK beef industry to select carcases that better meet abattoir specification and market requirements.

  8. Rank-ordered filter for edge enhancement of cellular images using interval type II fuzzy set.

    PubMed

    Chaira, Tamalika

    2015-10-01

    An edge-enhancement technique using an interval type II fuzzy set that uses rank-ordered filter to enhance the edges of cellular images is proposed. When cellular images from any laboratory are digitized, scanned, and stored, some kind of degradation occurs, and directly using a rank-ordered filter may not produce clear edges. These images contain uncertainties, present in edges or boundaries of the image. Fuzzy sets that take into account these uncertainties may be a good tool to process these images. However, a fuzzy set sometimes does not produce better results. We used an interval type II fuzzy set, which considers the uncertainty in a different way. It considers the membership function in the fuzzy set as "fuzzy," so the membership values lie within an interval range. A type II fuzzy set has upper and lower membership levels, and with the two levels, a new membership function is computed using Hamacher t-conorm. A new fuzzy image is formed. A rank-ordered filter is applied to the image to obtain an edge-enhanced image. The proposed method is compared with the existing methods visually and quantitatively using entropic method. Entropy of the proposed method is higher (0.4418) than the morphology method (0.2275), crisp method (0.3599), and Sobel method (0.2669), implying that the proposed method is better.

  9. Rank-ordered filter for edge enhancement of cellular images using interval type II fuzzy set

    PubMed Central

    Chaira, Tamalika

    2015-01-01

    Abstract. An edge-enhancement technique using an interval type II fuzzy set that uses rank-ordered filter to enhance the edges of cellular images is proposed. When cellular images from any laboratory are digitized, scanned, and stored, some kind of degradation occurs, and directly using a rank-ordered filter may not produce clear edges. These images contain uncertainties, present in edges or boundaries of the image. Fuzzy sets that take into account these uncertainties may be a good tool to process these images. However, a fuzzy set sometimes does not produce better results. We used an interval type II fuzzy set, which considers the uncertainty in a different way. It considers the membership function in the fuzzy set as “fuzzy,” so the membership values lie within an interval range. A type II fuzzy set has upper and lower membership levels, and with the two levels, a new membership function is computed using Hamacher t-conorm. A new fuzzy image is formed. A rank-ordered filter is applied to the image to obtain an edge-enhanced image. The proposed method is compared with the existing methods visually and quantitatively using entropic method. Entropy of the proposed method is higher (0.4418) than the morphology method (0.2275), crisp method (0.3599), and Sobel method (0.2669), implying that the proposed method is better. PMID:26702406

  10. Cutting tool form compensaton system and method

    DOEpatents

    Barkman, William E.; Babelay, Jr., Edwin F.; Klages, Edward J.

    1993-01-01

    A compensation system for a computer-controlled machining apparatus having a controller and including a cutting tool and a workpiece holder which are movable relative to one another along a preprogrammed path during a machining operation utilizes a camera and a vision computer for gathering information at a preselected stage of a machining operation relating to the actual shape and size of the cutting edge of the cutting tool and for altering the preprogrammed path in accordance with detected variations between the actual size and shape of the cutting edge and an assumed size and shape of the cutting edge. The camera obtains an image of the cutting tool against a background so that the cutting tool and background possess contrasting light intensities, and the vision computer utilizes the contrasting light intensities of the image to locate points therein which correspond to points along the actual cutting edge. Following a series of computations involving the determining of a tool center from the points identified along the tool edge, the results of the computations are fed to the controller where the preprogrammed path is altered as aforedescribed.

  11. Cutting tool form compensation system and method

    DOEpatents

    Barkman, W.E.; Babelay, E.F. Jr.; Klages, E.J.

    1993-10-19

    A compensation system for a computer-controlled machining apparatus having a controller and including a cutting tool and a workpiece holder which are movable relative to one another along a preprogrammed path during a machining operation utilizes a camera and a vision computer for gathering information at a preselected stage of a machining operation relating to the actual shape and size of the cutting edge of the cutting tool and for altering the preprogrammed path in accordance with detected variations between the actual size and shape of the cutting edge and an assumed size and shape of the cutting edge. The camera obtains an image of the cutting tool against a background so that the cutting tool and background possess contrasting light intensities, and the vision computer utilizes the contrasting light intensities of the image to locate points therein which correspond to points along the actual cutting edge. Following a series of computations involving the determining of a tool center from the points identified along the tool edge, the results of the computations are fed to the controller where the preprogrammed path is altered as aforedescribed. 9 figures.

  12. Image analysis tools to quantify cell shape and protein dynamics near the leading edge.

    PubMed

    Ryan, Gillian L; Watanabe, Naoki; Vavylonis, Dimitrios

    2013-01-01

    We present a set of flexible image analysis tools to analyze dynamics of cell shape and protein concentrations near the leading edge of cells adhered to glass coverslips. Plugins for ImageJ streamline common analyses of microscopic images of cells, including the calculation of leading edge speeds, total and average intensities of fluorescent markers, and retrograde flow rate measurements of fluorescent single-molecule speckles. We also provide automated calculations of auto- and cross-correlation functions between velocity and intensity measurements. The application of the methods is illustrated on images of XTC cells.

  13. BgCut: Automatic Ship Detection from UAV Images

    PubMed Central

    Zhang, Zhengning; Feng, Zhiyong

    2014-01-01

    Ship detection in static UAV aerial images is a fundamental challenge in sea target detection and precise positioning. In this paper, an improved universal background model based on Grabcut algorithm is proposed to segment foreground objects from sea automatically. First, a sea template library including images in different natural conditions is built to provide an initial template to the model. Then the background trimap is obtained by combing some templates matching with region growing algorithm. The output trimap initializes Grabcut background instead of manual intervention and the process of segmentation without iteration. The effectiveness of our proposed model is demonstrated by extensive experiments on a certain area of real UAV aerial images by an airborne Canon 5D Mark. The proposed algorithm is not only adaptive but also with good segmentation. Furthermore, the model in this paper can be well applied in the automated processing of industrial images for related researches. PMID:24977182

  14. BgCut: automatic ship detection from UAV images.

    PubMed

    Xu, Chao; Zhang, Dongping; Zhang, Zhengning; Feng, Zhiyong

    2014-01-01

    Ship detection in static UAV aerial images is a fundamental challenge in sea target detection and precise positioning. In this paper, an improved universal background model based on Grabcut algorithm is proposed to segment foreground objects from sea automatically. First, a sea template library including images in different natural conditions is built to provide an initial template to the model. Then the background trimap is obtained by combing some templates matching with region growing algorithm. The output trimap initializes Grabcut background instead of manual intervention and the process of segmentation without iteration. The effectiveness of our proposed model is demonstrated by extensive experiments on a certain area of real UAV aerial images by an airborne Canon 5D Mark. The proposed algorithm is not only adaptive but also with good segmentation. Furthermore, the model in this paper can be well applied in the automated processing of industrial images for related researches.

  15. Evaluation of edge effect due to phase contrast imaging for mammography.

    PubMed

    Matsuo, Satoru; Katafuchi, Tetsuro; Tohyama, Keiko; Morishita, Junji; Yamada, Katsuhiko; Fujita, Hiroshi

    2005-08-01

    It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase contrast imaging with x-ray from synchrotron radiation or micro-focus x-ray tubes. In this study, we conducted the phase contrast imaging of a plastic fiber and plant seeds using a customized mammography equipment with a 0.1 mm focal spot, and the improvement of image sharpness was evaluated in terms of spatial frequency response of the images. We observed that the image contrast of the plastic fiber was increased by edge enhancement, and, as predicted elsewhere, spectral analysis revealed that as the spatial frequencies of the x-ray images increased, so did the sharpness gained through phase contrast imaging. Thus, phase contrast imaging using a practical molybdenum anode tube with a 0.1 mm-focal spot would benefit mammography, in which the morphological detectability of small species such as microcalcifications is of great concern. And detectability of tumor-surrounded glandular tissues in dense breast would be also improved by the phase contrast imaging.

  16. Direct imaging of topological edge states at a bilayer graphene domain wall.

    PubMed

    Yin, Long-Jing; Jiang, Hua; Qiao, Jia-Bin; He, Lin

    2016-06-17

    The AB-BA domain wall in gapped graphene bilayers is a rare naked structure hosting topological electronic states. Although it has been extensively studied in theory, a direct imaging of its topological edge states is still missing. Here we image the topological edge states at the graphene bilayer domain wall by using scanning tunnelling microscope. The simultaneously obtained atomic-resolution images of the domain wall provide us unprecedented opportunities to measure the spatially varying edge states within it. The one-dimensional conducting channels are observed to be mainly located around the two edges of the domain wall, which is reproduced quite well by our theoretical calculations. Our experiment further demonstrates that the one-dimensional topological states are quite robust even in the presence of high magnetic fields. The result reported here may raise hopes of graphene-based electronics with ultra-low dissipation.

  17. The registration of dual-modality ship target images based on edge extraction

    NASA Astrophysics Data System (ADS)

    Zhang, Weimin; Wang, Risheng; Zhou, Fugen

    2014-11-01

    In this paper, we study the problem of visible and IR(infrared) ship target image registration with scale changes. We mainly focus on the infrared and visible image feature extraction and matching method. A method based on Force Field Transformation is used to determine the ship target contour area. Canny edge detection method is applied to obtain the edge features. During the process of image registration, we take the cross-correlation as the similarity measure and propose an improved Powell algorithm based on multi-scale searching to optimize the registration parameters. Through the edge fusion results, we can see the corresponding edges are almost overlapped, indicating that the method could achieve satisfying results. Also the average error distance of match is less than one pixel.

  18. Multispectral image sharpening using a shift-invariant wavelet transform and adaptive processing of multiresolution edges

    USGS Publications Warehouse

    Lemeshewsky, G.P.; Rahman, Z.-U.; Schowengerdt, R.A.; Reichenbach, S.E.

    2002-01-01

    Enhanced false color images from mid-IR, near-IR (NIR), and visible bands of the Landsat thematic mapper (TM) are commonly used for visually interpreting land cover type. Described here is a technique for sharpening or fusion of NIR with higher resolution panchromatic (Pan) that uses a shift-invariant implementation of the discrete wavelet transform (SIDWT) and a reported pixel-based selection rule to combine coefficients. There can be contrast reversals (e.g., at soil-vegetation boundaries between NIR and visible band images) and consequently degraded sharpening and edge artifacts. To improve performance for these conditions, I used a local area-based correlation technique originally reported for comparing image-pyramid-derived edges for the adaptive processing of wavelet-derived edge data. Also, using the redundant data of the SIDWT improves edge data generation. There is additional improvement because sharpened subband imagery is used with the edge-correlation process. A reported technique for sharpening three-band spectral imagery used forward and inverse intensity, hue, and saturation transforms and wavelet-based sharpening of intensity. This technique had limitations with opposite contrast data, and in this study sharpening was applied to single-band multispectral-Pan image pairs. Sharpening used simulated 30-m NIR imagery produced by degrading the spatial resolution of a higher resolution reference. Performance, evaluated by comparison between sharpened and reference image, was improved when sharpened subband data were used with the edge correlation.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Edge guided image reconstruction in linear scan CT by weighted alternating direction TV minimization.

    PubMed

    Cai, Ailong; Wang, Linyuan; Zhang, Hanming; Yan, Bin; Li, Lei; Xi, Xiaoqi; Li, Jianxin

    2014-01-01

    Linear scan computed tomography (CT) is a promising imaging configuration with high scanning efficiency while the data set is under-sampled and angularly limited for which high quality image reconstruction is challenging. In this work, an edge guided total variation minimization reconstruction (EGTVM) algorithm is developed in dealing with this problem. The proposed method is modeled on the combination of total variation (TV) regularization and iterative edge detection strategy. In the proposed method, the edge weights of intermediate reconstructions are incorporated into the TV objective function. The optimization is efficiently solved by applying alternating direction method of multipliers. A prudential and conservative edge detection strategy proposed in this paper can obtain the true edges while restricting the errors within an acceptable degree. Based on the comparison on both simulation studies and real CT data set reconstructions, EGTVM provides comparable or even better quality compared to the non-edge guided reconstruction and adaptive steepest descent-projection onto convex sets method. With the utilization of weighted alternating direction TV minimization and edge detection, EGTVM achieves fast and robust convergence and reconstructs high quality image when applied in linear scan CT with under-sampled data set.

  1. Edge Detection and Shape Recognition in Neutron Transmission Images

    SciTech Connect

    Sword, Eric D; McConchie, Seth M

    2012-01-01

    Neutron transmission measurements are a valuable tool for nondestructively imaging special nuclear materials. Analysis of these images, however, tends to require significant user interaction to determine the sizes, shapes, and likely compositions of measured objects. Computer vision (CV) techniques can be a useful approach to automatically extracting important information from either neutron transmission images or fission-site-mapping images. An automatable approach has been developed that processes an input image and, through recursive application of CV techniques, produces a set of basic shapes that define surfaces observed in the image. These shapes can then be compared to a library of known shape configurations to determine if the measured object matches its expected configuration, as could be done behind an information barrier for arms control treaty verification inspections.

  2. Deep Edge Guided Recurrent Residual Learning for Image Super-Resolution.

    PubMed

    Yang, Wenhan; Feng, Jiashi; Yang, Jianchao; Zhao, Fang; Liu, Jiaying; Guo, Zongming; Yan, Shuicheng

    2017-09-08

    In this work, we consider the image super-resolution (SR) problem. The main challenge of image SR is to recover high-frequency details of a low-resolution (LR) image that are important for human perception. To address this essentially illposed problem, we introduce a Deep Edge Guided REcurrent rEsidual (DEGREE) network to progressively recover the highfrequency details. Different from most of existing methods that aim at predicting high-resolution (HR) images directly, DEGREE investigates an alternative route to recover the difference between a pair of LR and HR images by recurrent residual learning. DEGREE further augments the SR process with edge-preserving capability, namely the LR image and its edge map can jointly infer the sharp edge details of the HR image during the recurrent recovery process. To speed up its training convergence rate, by-pass connections across multiple layers of DEGREE are constructed. In addition, we offer an understanding on DEGREE from the view-point of sub-band frequency decomposition on image signal and experimentally demonstrate how DEGREE can recover different frequency bands separately. Extensive experiments on three benchmark datasets clearly demonstrate the superiority of DEGREE over well-established baselines and DEGREE also provides new state-of-the-arts on these datasets. We also present addition experiments for JPEG artifacts reduction to demonstrate the good generality and flexibility of our proposed DEGREE network to handle other image processing tasks.

  3. Analysis of edge effects in attenuating phase-shift masks using quantitative phase imaging

    NASA Astrophysics Data System (ADS)

    Shanker, Aamod; Sczyrba, Martin; Connolly, Brid; Neureuther, Andy; Waller, Laura

    2013-09-01

    Thick mask electromagnetic edge effects in attenuating phase-shift masks (ATT-PSM) are analyzed by extracting optical phase at the wafer plane from a series of through focus aerial images with 193nm light. The thick edges of an ATT-PSM can lead to phase distortions, creating asymmetric intensity contrast on either side of focus. Here we use through focus intensity images from an AIMS tool to quantitatively recover phase via the Transport of Intensity Equation (TIE). The TIE can recover the effective phase across the mask due to edge effects by analyzing the through focus image stack. We verify a previously proposed model for edge effects by adding quadrature phase boundary layers at the edges during simulation and compare the simulated through focus images with experimental data. After tuning the real and imaginary part of the boundary layer and the angle of the substrate, the simulated through focus behavior agrees with experiment, giving a measure of the edge effects. This leads to comparable quantitative phase profiles recovered at the wafer plane for simulation and experiment with the ATT-PSM. We expect that the method is applicable for the approximation of topographical effects in other types of thick masks as well.

  4. The roles of image decomposition and edge curvature in the 'snake' lightness illusion.

    PubMed

    Todorović, Dejan; Zdravković, Sunčica

    2014-04-01

    The snake illusion is an effect in which the lightness of target patches is strongly affected by the luminance of remote patches. One explanation is that such images are decomposed into a pattern of illumination and a pattern of reflectance, involving a classification of luminance edges into illumination and reflectance edges. Based on this decomposition, perceived reflectance is determined by discounting the illumination. A problem for this account is that image decomposition is not unique, and that different decompositions may lead to different lightness predictions. One way to rule out alternative decompositions and ensure correct predictions is to postulate that the visual system tends to classify curved luminance edges as reflectance edges rather than illumination edges. We have constructed several variations of the basic snake display in order to test the proposed curvature constraint and the more general image decomposition hypothesis. Although the results from some displays have confirmed previous findings of the effect of curvature, the general pattern of data questions the relevance of the shape of luminance edges for the determination of lightness in this class of displays. The data also argue against an image decomposition mechanism as an explanation of this effect. As an alternative, a tentative neurally based account is sketched.

  5. Multispectral image sharpening using wavelet transform techniques and spatial correlation of edges

    USGS Publications Warehouse

    Lemeshewsky, George P.; Schowengerdt, Robert A.

    2000-01-01

    Several reported image fusion or sharpening techniques are based on the discrete wavelet transform (DWT). The technique described here uses a pixel-based maximum selection rule to combine respective transform coefficients of lower spatial resolution near-infrared (NIR) and higher spatial resolution panchromatic (pan) imagery to produce a sharpened NIR image. Sharpening assumes a radiometric correlation between the spectral band images. However, there can be poor correlation, including edge contrast reversals (e.g., at soil-vegetation boundaries), between the fused images and, consequently, degraded performance. To improve sharpening, a local area-based correlation technique originally reported for edge comparison with image pyramid fusion is modified for application with the DWT process. Further improvements are obtained by using redundant, shift-invariant implementation of the DWT. Example images demonstrate the improvements in NIR image sharpening with higher resolution pan imagery.

  6. The cutting edges in DNA repair, licensing, and fidelity: DNA and RNA repair nucleases sculpt DNA to measure twice, cut once

    PubMed Central

    Lafrance-Vanasse, Julien

    2014-01-01

    To avoid genome instability, DNA repair nucleases must precisely target the correct damaged substrate before they are licensed to incise. Damage identification is a challenge for all DNA damage response proteins, but especially for nucleases that cut the DNA and necessarily create a cleaved DNA repair intermediate, likely more toxic than the initial damage. How do these enzymes achieve exquisite specificity without specific sequence recognition or, in some cases, without a non-canonical DNA nucleotide? Combined structural, biochemical, and biological analyses of repair nucleases are revealing their molecular tools for damage verification and safeguarding against inadvertent incision. Surprisingly, these enzymes also often act on RNA, which deserves more attention. Here, we review protein-DNA structures for nucleases involved in replication, base excision repair, mismatch repair, double strand break repair (DSBR), and telomere maintenance: apurinic/apyrimidinic endonuclease 1 (APE1), Endonuclease IV (Nfo), tyrosyl DNA phosphodiesterase (TDP2), UV Damage endonuclease (UVDE), very short patch repair endonuclease (Vsr), Endonuclease V (Nfi), Flap endonuclease 1 (FEN1), exonuclease 1 (Exo1), RNase T and Meiotic recombination 11 (Mre11). DNA and RNA structure-sensing nucleases are essential to life with roles in DNA replication, repair, and transcription. Increasingly these enzymes are employed as advanced tools for synthetic biology and as targets for cancer prognosis and interventions. Currently their structural biology is most fully illuminated for DNA repair, which is also essential to life. How DNA repair enzymes maintain genome fidelity is one of the DNA double helix secrets missed by Watson-Crick, that is only now being illuminated though structural biology and mutational analyses. Structures reveal motifs for repair nucleases and mechanisms whereby these enzymes follow the old carpenter adage: measure twice, cut once. Furthermore, to measure twice these nucleases

  7. Semi-automatic breast ultrasound image segmentation based on mean shift and graph cuts.

    PubMed

    Zhou, Zhuhuang; Wu, Weiwei; Wu, Shuicai; Tsui, Po-Hsiang; Lin, Chung-Chih; Zhang, Ling; Wang, Tianfu

    2014-10-01

    Computerized tumor segmentation on breast ultrasound (BUS) images remains a challenging task. In this paper, we proposed a new method for semi-automatic tumor segmentation on BUS images using Gaussian filtering, histogram equalization, mean shift, and graph cuts. The only interaction required was to select two diagonal points to determine a region of interest (ROI) on an input image. The ROI image was shrunken by a factor of 2 using bicubic interpolation to reduce computation time. The shrunken image was smoothed by a Gaussian filter and then contrast-enhanced by histogram equalization. Next, the enhanced image was filtered by pyramid mean shift to improve homogeneity. The object and background seeds for graph cuts were automatically generated on the filtered image. Using these seeds, the filtered image was then segmented by graph cuts into a binary image containing the object and background. Finally, the binary image was expanded by a factor of 2 using bicubic interpolation, and the expanded image was processed by morphological opening and closing to refine the tumor contour. The method was implemented with OpenCV 2.4.3 and Visual Studio 2010 and tested for 38 BUS images with benign tumors and 31 BUS images with malignant tumors from different ultrasound scanners. Experimental results showed that our method had a true positive rate (TP) of 91.7%, a false positive (FP) rate of 11.9%, and a similarity (SI) rate of 85.6%. The mean run time on Intel Core 2.66 GHz CPU and 4 GB RAM was 0.49 ± 0.36 s. The experimental results indicate that the proposed method may be useful in BUS image segmentation. © The Author(s) 2014.

  8. Image demosaic via Nevatia-Babu edge detection

    NASA Astrophysics Data System (ADS)

    Reinhart, Craig; Bodie, James

    2007-02-01

    A template matching approach is used to demosaic (reconstruct) a full color image from the sparse pixel data captured by a CMOS imager. The proposed method is based on the Nevatia-Babu template-based linear feature extraction algorithm. This approach provides the color accuracy of gradient based algorithms yet reaps the benefit of regularity of processing of bilinear interpolation. In this paper we describe the algorithm (gradient estimation and color interpolation), compare results to other approaches, and present a hardware implementation. The consideration of hardware implementation is especially important as CMOS imagers find their way into low cost devices such as cell phones and other novelty camera applications.

  9. An image matching method based on closed edges incorporated with vertex angles

    NASA Astrophysics Data System (ADS)

    Zhang, Baoming; Chen, Xiaowei; Lu, Jun; Gong, Zhihui; Guo, Haitao

    2015-10-01

    An image matching method based on closed edges incorporated with vertex angles is proposed in this paper. Based on edge detection results by Edison operator, invariant moments of closed edges and angles between the two branches for edge vertexes are used as matching entities to determine conjugate features candidates. The transformation relationship between images is approximated by similarity transformation model, and a set of transformation parameters can be determined by each pair of conjugate features after combining conjugate feature candidates in pair-wise. Furthermore, considering that the difference among transformation parameters which calculated by real conjugate features are minor, K-d tree method and K-means Spatial clustering method are used in succession to eliminate pairs which contain mismatching features. Therefore, conjugate features can be obtained from the similarity transformation parameters. Experimental results turn out that this method shows a stable performance and presents a satisfactory matching result.

  10. Atomic-scale imaging of few-layer black phosphorus and its reconstructed edge

    NASA Astrophysics Data System (ADS)

    Lee, Yangjin; Yoon, Jun-Yeong; Scullion, Declan; Jang, Jeongsu; Santos, Elton J. G.; Jeong, Hu Young; Kim, Kwanpyo

    2017-03-01

    Black phosphorus (BP) has recently emerged as an alternative 2D semiconductor owing to its fascinating electronic properties such as tunable bandgap and high charge carrier mobility. The structural investigation of few-layer BP, such as identification of layer thickness and atomic-scale edge structure, is of great importance to fully understand its electronic and optical properties. Here we report atomic-scale analysis of few-layered BP performed by aberration corrected transmission electron microscopy (TEM). We establish the layer-number-dependent atomic resolution imaging of few-layer BP via TEM imaging and image simulations. The structural modification induced by the electron beam leads to revelation of crystalline edge and formation of BP nanoribbons. Atomic resolution imaging of BP clearly shows the reconstructed zigzag (ZZ) edge structures, which is also corroborated by van der Waals first principles calculations on the edge stability. Our study on the precise identification of BP thickness and atomic-resolution imaging of edge structures will lay the groundwork for investigation of few-layer BP, especially BP in nanostructured forms.

  11. Combining volumetric edge display and multiview display for expression of natural 3D images

    NASA Astrophysics Data System (ADS)

    Yasui, Ryota; Matsuda, Isamu; Kakeya, Hideki

    2006-02-01

    In the present paper the authors present a novel stereoscopic display method combining volumetric edge display technology and multiview display technology to realize presentation of natural 3D images where the viewers do not suffer from contradiction between binocular convergence and focal accommodation of the eyes, which causes eyestrain and sickness. We adopt volumetric display method only for edge drawing, while we adopt stereoscopic approach for flat areas of the image. Since focal accommodation of our eyes is affected only by the edge part of the image, natural focal accommodation can be induced if the edges of the 3D image are drawn on the proper depth. The conventional stereo-matching technique can give us robust depth values of the pixels which constitute noticeable edges. Also occlusion and gloss of the objects can be roughly expressed with the proposed method since we use stereoscopic approach for the flat area. We can attain a system where many users can view natural 3D objects at the consistent position and posture at the same time in this system. A simple optometric experiment using a refractometer suggests that the proposed method can give us 3-D images without contradiction between binocular convergence and focal accommodation.

  12. Compensation of extreme ultraviolet lithography image field edge effects through optical proximity correction

    NASA Astrophysics Data System (ADS)

    Maloney, Chris

    For EUVL to be enabled for HVM, the printing of densely spaced die must be allowed. To achieve this requirement, a mitigation strategy to compensate for field edge effects is vital. This study has two goals. First, we will show that field edge effects can be modeled for reticles with an absorber border and for those with an etched ML border. The second is to investigate the limitations that exist when compensating for field edge effects with OPC, including image quality, REMA blade stability and OoB variability. This thesis shows that for different reticles different mitigation strategies are required in order to enable EUV HVM.

  13. Edge detection in untextured and textured images-a common computational framework.

    PubMed

    Ganesan, L; Bhattacharyya, P

    1997-01-01

    In this paper, a unified computational framework is presented for facilitating edge detection both in untextured as well as textured two-dimensional (2-D) images. The framework is based on a complete set of difference operators which are easily configurable from a set of orthogonal polynomials. The widely known Roberts, Sobel, Prewitt, and Marr's LOG edge operators can easily be represented in terms of these operators. For detection of untextured or textured edges, the proposed operators are employed to separate out the responses toward edge or texture and noise. Untextured edges are detected by maximizing signal-to-noise ratio (SNR) or identifying the zero crossings in the second directional derivatives. Textured edges are detected in two stages. First, the significance of responses toward texture is computed statistically in order to test the presence of microtexture and compute a local descriptor called "pronum" for its representation. Finally, a global descriptor for texture called "prospectrum" is obtained by observing the frequency of occurrence of pronums. The textured edges are detected at the second stage by applying the methods of detection of untextured edges on these prospectrums. The results are encouraging.

  14. The segmentation of the CT image based on k clustering and graph-cut

    NASA Astrophysics Data System (ADS)

    Chen, Yuke; Wu, Xiaoming; Yang, Rongqian; Ou, Shanxin; Cai, Ken; Chen, Hai

    2011-11-01

    Computed tomography angiography (CTA) is widely used to assess heart disease, like coronary artery disease. In order to complete the auto-segmentation of cardiac image of dual-source CT (DSCT) and extract the structure of heart accurately, this paper proposes a hybrid segmentation method based on k clustering and Graph-Cuts (GC). It identifies the initial label of pixels by this method. Based on this, it creates the energy function of the label with the knowledge of anatomic construction of heart and constructs the network diagram. Finally, it minimizes the energy function by the method of max-flow/min-cut theorem and picks up region of interest. The experiment results indicate that the robust, accurate segmentation of the cardiac DSCT image can be realized by combining Graph-Cut and k clustering algorithm.

  15. Using neural networks to locate edges and linear features in satellite images

    NASA Astrophysics Data System (ADS)

    Penn, B. S.; Gordon, A. J.; Wendlandt, R. F.

    1993-11-01

    Edges and linear features are manifestations of discontinuities. In geologic applications of satellite imagery, edges and linear features are used to identify faults, lineaments, or lithology changes. Two techniques for detecting these types of features in satellite imagery are skilled human interpretation and mathematical manipulation (e.g. Fourier analysis). The former approach has the advantage of being able to learn, combined with a high degree of fault tolerance. Disadvantages to this approach are that it is labor intensive (slow) and somewhat arbitrary in its decision process. The latter approach is purely mathematical and, when implemented on a computer, is fast and consistent. The disadvantages of the mathematical approach are the lack of both fault tolerance and learning ability. A third approach, applied here, is to use neural networks (NNs). NNs combine the speed and accuracy of computers with the fault tolerance of human beings. NNs are arrays of highly interconnected, simple processing units which excel at pattern recognition. Because of this ability, they are appropriate tools for recognizing edges and linear features in two-dimensional (2-D) data, such as satellite imagery, aeromagnetic, and gravity data. Image interpretation is comprised of two phases. The syntactic phase identifies image primitives such as lines and edges, and the semantic phase resolves the meaning of the lines and edges. This study focused on the first aspect of locating syntactical information in an image. We determined that NNs are of only limited use for detecting linear features, but they are capable of detecting edges at various scales.

  16. Run-Length and Edge Statistics Based Approach for Image Splicing Detection

    NASA Astrophysics Data System (ADS)

    Dong, Jing; Wang, Wei; Tan, Tieniu; Shi, Yun Q.

    In this paper, a simple but efficient approach for blind image splicing detection is proposed. Image splicing is a common and fundamental operation used for image forgery. The detection of image splicing is a preliminary but desirable study for image forensics. Passive detection approaches of image splicing are usually regarded as pattern recognition problems based on features which are sensitive to splicing. In the proposed approach, we analyze the discontinuity of image pixel correlation and coherency caused by splicing in terms of image run-length representation and sharp image characteristics. The statistical features extracted from image run-length representation and image edge statistics are used for splicing detection. The support vector machine (SVM) is used as the classifier. Our experimental results demonstrate that the two proposed features outperform existing ones both in detection accuracy and computational complexity.

  17. Novel lattice Boltzmann method based on integrated edge and region information for medical image segmentation.

    PubMed

    Wen, Junling; Yan, Zhuangzhi; Jiang, Jiehui

    2014-01-01

    The lattice Boltzmann (LB) method is a mesoscopic method based on kinetic theory and statistical mechanics. The main advantage of the LB method is parallel computation, which increases the speed of calculation. In the past decade, LB methods have gradually been introduced for image processing, e.g., image segmentation. However, a major shortcoming of existing LB methods is that they can only be applied to the processing of medical images with intensity homogeneity. In practice, however, many medical images possess intensity inhomogeneity. In this study, we developed a novel LB method to integrate edge and region information for medical image segmentation. In contrast to other segmentation methods, we added edge information as a relaxing factor and used region information as a source term. The proposed method facilitates the segmentation of medical images with intensity inhomogeneity and it still allows parallel computation. Preliminary tests of the proposed method are presented in this paper.

  18. A novel edge detection in medical images by fusing of multi-model from different spatial structure clues.

    PubMed

    Jia, Xibin; Huang, Haiyong; Wang, Runyuan

    2014-01-01

    Edge detection has been widely used in medical image processing, automatic diagnosis, et al. A novel edge detection algorithm, based on the fusion model, is proposed by combination with the two proposed models as follows: the matrix of most probable distribution of edge point and the matrix of the difference weight of each point. The most probable distribution of edge point can be obtained by analyzing the variance among 4-connected neighborhood points around each pixel under estimation in the image to label the all candidate edge points in the image. The difference weight of each point can be gotten by analyzing the brightness difference between the neighborhood point and the under-estimating pixel to represent the probability of being edge. The two matrices gotten from the different descriptions of spatial structure are fused together and derive from the final edge image with thresholding method on the fusion matrix. The experiments are performed based on the public diabetic retinopathy database DRIVE. According to the edge images obtained, the proposed method is subjectively analyzed to be complete and close to the Ground Truth image with very low noise in comparison with the Sobel, Canny and LOG edge detectors. The F1 measure, ROC measure and PFOM measure are separately adopted to make quantitative evaluation of the proposed edge detection algorithm. Experimental results show that the proposed method is able to improve the effect of edge detection on medical images.

  19. Surface and cut-edge corrosion behavior of Zn-Mg-Al alloy-coated steel sheets as a function of the alloy coating microstructure

    NASA Astrophysics Data System (ADS)

    Oh, Min-Suk; Kim, Sang-Heon; Kim, Jong-Sang; Lee, Jae-Won; Shon, Je-Ha; Jin, Young-Sool

    2016-01-01

    The effects of Mg and Al content on the microstructure and corrosion resistance of hot-dip Zn-Mg-Al alloycoated steel sheets were investigated. Pure Zn and Zn-based alloy coatings containing Mg (0-5 wt%) and Al (0.2-55 wt%) were produced by a hot-dip galvanizing method. Mg and Al addition induced formation of intermetallic microstructures, like primary Zn, Zn/MgZn2 binary eutectic, dendric Zn/Al eutectoid, and Zn/Al/MgZn2/ternary eutectic structures in the coating layer. MgZn2-related structures (Zn/MgZn2, Zn/Al/MgZn2, MgZn2) played an important role in increasing the corrosion resistance of Zn-Mg-Al alloy-coated steel sheets. Zn-3%Mg-2.5%Al coating layer containing a large volume of lamellar-shaped Zn/MgZn2 binary eutectic structures showed the best cut-edge corrosion resistance. The analysis indicated that Mg dissolved from MgZn2 in the early stage of corrosion and migrated to the cathodic region of steel-exposed cut-edge area to form dense and ordered protective corrosion products, leading to prolonged cathodic protection of Zn-Mg-Al alloy-coated steel sheets.

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  1. Automatic Assessment and Reduction of Noise using Edge Pattern Analysis in Non-Linear Image Enhancement

    NASA Technical Reports Server (NTRS)

    Jobson, Daniel J.; Rahman, Zia-Ur; Woodell, Glenn A.; Hines, Glenn D.

    2004-01-01

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

  2. Assessment of transmitral flow after mitral valve edge-to-edge repair using High-speed particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Jeyhani, Morteza; Shahriari, Shahrokh; Labrosse, Michel; Kadem, Lyes

    2013-11-01

    Approximately 500,000 people in North America suffer from mitral valve regurgitation (MR). MR is a disorder of the heart in which the mitral valve (MV) leaflets do not close securely during systole. Edge-to-edge repair (EtER) technique can be used to surgically treat MR. This technique produces a double-orifice configuration for the MV. Under these un-physiological conditions, flow downstream of the MV forms a double jet structure that may disturb the intraventricular hemodynamics. Abnormal flow patterns following EtER are mainly characterized by high-shear stress and stagnation zones in the left ventricle (LV), which increase the potential of blood component damage. In this study, a custom-made prosthetic bicuspid MV was used to analyze the LV flow patterns after EtER by means of digital particle image velocimetry (PIV). Although the repair of a MV using EtER technique is an effective approach, this study confirms that EtER leads to changes in the LV flow field, including the generation of a double mitral jet flow and high shear stress regions.

  3. Invited Review Article: Gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion devices

    DOE PAGES

    Zweben, S. J.; Terry, J. L.; Stotler, D. P.; ...

    2017-04-27

    Gas puff imaging (GPI) is a diagnostic of plasma turbulence which uses a puff of neutral gas at the plasma edge to increase the local visible light emission for improved space-time resolution of plasma fluctuations. This paper reviews gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion research, with a focus on the instrumentation, diagnostic cross-checks, and interpretation issues. The gas puff imaging hardware, optics, and detectors are described for about 10 GPI systems implemented over the past similar to 15 years. Comparison of GPI results with other edge turbulence diagnostic results is described, and many common featuresmore » are observed. Here, several issues in the interpretation of GPI measurements are discussed, and potential improvements in hardware and modeling are suggested.« less

  4. Bladder segmentation in MR images with watershed segmentation and graph cut algorithm

    NASA Astrophysics Data System (ADS)

    Blaffert, Thomas; Renisch, Steffen; Schadewaldt, Nicole; Schulz, Heinrich; Wiemker, Rafael

    2014-03-01

    Prostate and cervix cancer diagnosis and treatment planning that is based on MR images benefit from superior soft tissue contrast compared to CT images. For these images an automatic delineation of the prostate or cervix and the organs at risk such as the bladder is highly desirable. This paper describes a method for bladder segmentation that is based on a watershed transform on high image gradient values and gray value valleys together with the classification of watershed regions into bladder contents and tissue by a graph cut algorithm. The obtained results are superior if compared to a simple region-after-region classification.

  5. Edge-on illumination photon-counting for medical imaging

    NASA Astrophysics Data System (ADS)

    Doni, M.; Visser, J.; Koffeman, E.; Herrmann, C.

    2015-08-01

    In medical X-ray Computed Tomography (CT) a silicon based sensor (300-1000 μm) in face-on configuration does not collect the incoming X-rays effectively because of their high energy (40-140 keV). For example, only 2% of the incoming photons at 100 keV are stopped by a 500 μm thick silicon layer. To increase the efficiency, one possibility is to use materials with higher Z (e.g. GaAs, CZT), which have some drawbacks compared to silicon, such as short carrier lifetime or low mobility. Therefore, we investigate whether illuminating silicon edge-on instead of face-on is a solution. Aim of the project is to find and take advantage of the benefits of this new geometry when used for a pixel detector. In particular, we employ a silicon hybrid pixel detector, which is read out by a chip from the Medipix family. Its capabilities to be energy selective will be a notable advantage in energy resolved (spectral) X-ray CT.

  6. Combining STEREO SECCHI COR2 and HI1 images for automatic CME front edge tracking

    NASA Astrophysics Data System (ADS)

    Kirnosov, Vladimir; Chang, Lin-Ching; Pulkkinen, Antti

    2016-12-01

    COR2 coronagraph images are the most commonly used data for coronal mass ejection (CME) analysis among the various types of data provided by the STEREO (Solar Terrestrial Relations Observatory) SECCHI (Sun-Earth Connection Coronal and Heliospheric Investigation) suite of instruments. The field of view (FOV) in COR2 images covers 2-15 solar radii (Rs) that allow for tracking the front edge of a CME in its initial stage to forecast the lead-time of a CME and its chances of reaching the Earth. However, estimating the lead-time of a CME using COR2 images gives a larger lead-time, which may be associated with greater uncertainty. To reduce this uncertainty, CME front edge tracking should be continued beyond the FOV of COR2 images. Therefore, heliospheric imager (HI1) data that covers 15-90 Rs FOV must be included. In this paper, we propose a novel automatic method that takes both COR2 and HI1 images into account and combine the results to track the front edges of a CME continuously. The method consists of two modules: pre-processing and tracking. The pre-processing module produces a set of segmented images, which contain the signature of a CME, for both COR2 and HI1 separately. In addition, the HI1 images are resized and padded, so that the center of the Sun is the central coordinate of the resized HI1 images. The resulting COR2 and HI1 image set is then fed into the tracking module to estimate the position angle (PA) and track the front edge of a CME. The detected front edge is then used to produce a height-time profile that is used to estimate the speed of a CME. The method was validated using 15 CME events observed in the period from January 1, 2008 to August 31, 2009. The results demonstrate that the proposed method is effective for CME front edge tracking in both COR2 and HI1 images. Using this method, the CME front edge can now be tracked automatically and continuously in a much larger range, i.e., from 2 to 90 Rs, for the first time. These improvements can

  7. Combining Stereo SECCHI COR2 and HI1 Images for Automatic CME Front Edge Tracking

    NASA Technical Reports Server (NTRS)

    Kirnosov, Vladimir; Chang, Lin-Ching; Pulkkinen, Antti

    2016-01-01

    COR2 coronagraph images are the most commonly used data for coronal mass ejection (CME) analysis among the various types of data provided by the STEREO (Solar Terrestrial Relations Observatory) SECCHI (Sun-Earth Connection Coronal and Heliospheric Investigation) suite of instruments. The field of view (FOV) in COR2 images covers 215 solar radii (Rs) that allow for tracking the front edge of a CME in its initial stage to forecast the lead-time of a CME and its chances of reaching the Earth. However, estimating the lead-time of a CME using COR2 images gives a larger lead-time, which may be associated with greater uncertainty. To reduce this uncertainty, CME front edge tracking should be continued beyond the FOV of COR2 images. Therefore, heliospheric imager (HI1) data that covers 1590 Rs FOV must be included. In this paper, we propose a novel automatic method that takes both COR2 and HI1 images into account and combine the results to track the front edges of a CME continuously. The method consists of two modules: pre-processing and tracking. The pre-processing module produces a set of segmented images, which contain the signature of a CME, for both COR2 and HI1 separately. In addition, the HI1 images are resized and padded, so that the center of the Sun is the central coordinate of the resized HI1 images. The resulting COR2 andHI1 image set is then fed into the tracking module to estimate the position angle (PA) and track the front edge of a CME. The detected front edge is then used to produce a height-time profile that is used to estimate the speed of a CME. The method was validated using 15 CME events observed in the period from January 1, 2008 to August 31, 2009. The results demonstrate that the proposed method is effective for CME front edge tracking in both COR2 and HI1 images. Using this method, the CME front edge can now be tracked automatically and continuously in a much larger range, i.e., from 2 to 90 Rs, for the first time. These improvement scan greatly

  8. Edge Enhancement in Cold Neutron Imaging: A Comparison of Experiments at Edges and Interfaces with Ray-tracing based on Refraction and Reflection

    NASA Astrophysics Data System (ADS)

    Butler, Leslie G.; Lehmann, Eberhard H.

    In the past decade, increased neutron image resolution with digital detectors, approaching 10 μm, combined with more images obtained with cold neutrons, i.e., with neutrons having wavelengths longer than 3 Å, have yielded many examples of edge en- hancement. Line profiles across an air-metal interface can show both reflection and refraction; in some samples, reflection can dominate while other samples show structure that is largely due to refraction. Thus far, evidence for Fresnel diffraction at sharp edges is lacking due to, as yet, insufficient detector resolution. With the exception of titanium, most common engineering metals have a neutron refractive index slightly less than one and application of geometrical optics such as Snell's law and the Fresnel equations show that edge enhancement is detectable for low attenuation samples at about 4 Å and rapidly grows at longer wave- lengths. Looking forward, imaging at a time-of-flight system could make use of the edge enhancement for sensitive detection of internal cracks and voids. Reduction, but not complete suppression, of edge enhancement is possible with close sample-to-detector distances. Edge enhancement effects have been shown to be determined by a number of parameters, both sample and beamline. As the range of samples grows, beamline performance increases, and the variety of imaging methods evolves, we should prepare for new examples of the edge enhancement effects as well as a change in the relative weights of reflection, refraction, and diffraction.

  9. Multidimensional EMD-based edge detection and the application to GPR imaging

    NASA Astrophysics Data System (ADS)

    Jeng, Yih; Chen, Chih-Sung; Chen, Sung-Chih

    2017-04-01

    The edge detection is an effective approach in identifying object boundaries within a digital image. In recent years, it has been introduced to process geophysical data in the hope of enhancing the target boundary and improving the delineation of geological structures. However, most successful cases are applications to potential-field data. For GPR imaging, the edge detection is an emerging technique, and much effort is needed to make this method become an essential GPR data processing component. The major difficulty of applying edge detection to GPR data is that the GPR profile is orientation dependent, and a method successful in processing the digital image or potential-field data may not have the same achievement in GPR. Another concern for applying the edge detection is that the data must have acceptable signal-to-noise ratios, but the signal enhancement in GPR imaging has not been completely solved yet. In this study, we introduce a multidimensional EMD-based edge detection which can reduce the mentioned difficulties and improve the effect of edge detection. The proposed scheme suggests that the GPR data are pre-processed and reconstructed by using the multidimensional EMD to enhance the signal to noise ratio. This procedure is decisive because the adaptability of the EMD decomposition and the dyadic nature of the EMD components both allow the reconstructed data to have less noise and retain more signal than using conventional filters. In addition, the multidimensional EMD is efficient in identifying structure in different directions, which is suitable for processing orientation dependent data. Moreover, all the advantages gained in the multidimensional EMD do not rely on any prerequisite knowledge of the noise frequency band. After the multidimensional EMD process, we then apply the edge detection to the reconstructed data for the final interpretation. With the typical model study, the proposed scheme is also tested on the GPR data acquired in a buried hot

  10. High quality image-pair-based deblurring method using edge mask and improved residual deconvolution

    NASA Astrophysics Data System (ADS)

    Cui, Guangmang; Zhao, Jufeng; Gao, Xiumin; Feng, Huajun; Chen, Yueting

    2017-04-01

    Image deconvolution problem is a challenging task in the field of image process. Using image pairs could be helpful to provide a better restored image compared with the deblurring method from a single blurred image. In this paper, a high quality image-pair-based deblurring method is presented using the improved RL algorithm and the gain-controlled residual deconvolution technique. The input image pair includes a non-blurred noisy image and a blurred image captured for the same scene. With the estimated blur kernel, an improved RL deblurring method based on edge mask is introduced to obtain the preliminary deblurring result with effective ringing suppression and detail preservation. Then the preliminary deblurring result is served as the basic latent image and the gain-controlled residual deconvolution is utilized to recover the residual image. A saliency weight map is computed as the gain map to further control the ringing effects around the edge areas in the residual deconvolution process. The final deblurring result is obtained by adding the preliminary deblurring result with the recovered residual image. An optical experimental vibration platform is set up to verify the applicability and performance of the proposed algorithm. Experimental results demonstrate that the proposed deblurring framework obtains a superior performance in both subjective and objective assessments and has a wide application in many image deblurring fields.

  11. High quality image-pair-based deblurring method using edge mask and improved residual deconvolution

    NASA Astrophysics Data System (ADS)

    Cui, Guangmang; Zhao, Jufeng; Gao, Xiumin; Feng, Huajun; Chen, Yueting

    2017-02-01

    Image deconvolution problem is a challenging task in the field of image process. Using image pairs could be helpful to provide a better restored image compared with the deblurring method from a single blurred image. In this paper, a high quality image-pair-based deblurring method is presented using the improved RL algorithm and the gain-controlled residual deconvolution technique. The input image pair includes a non-blurred noisy image and a blurred image captured for the same scene. With the estimated blur kernel, an improved RL deblurring method based on edge mask is introduced to obtain the preliminary deblurring result with effective ringing suppression and detail preservation. Then the preliminary deblurring result is served as the basic latent image and the gain-controlled residual deconvolution is utilized to recover the residual image. A saliency weight map is computed as the gain map to further control the ringing effects around the edge areas in the residual deconvolution process. The final deblurring result is obtained by adding the preliminary deblurring result with the recovered residual image. An optical experimental vibration platform is set up to verify the applicability and performance of the proposed algorithm. Experimental results demonstrate that the proposed deblurring framework obtains a superior performance in both subjective and objective assessments and has a wide application in many image deblurring fields.

  12. OPTICAL DATA PROCESSING: Two-dimensional image edge enhancement in the two-phonon diffraction

    NASA Astrophysics Data System (ADS)

    Kotov, V. M.; Averin, S. V.; Shkerdin, G. N.; Voronko, A. I.

    2010-06-01

    We suggest using the two-phonon Bragg scattering regime for two-dimensional image edge enhancement by means of acousto-optic (AO) diffraction on a single sound wave. Image edge enhancement is demonstrated in the first diffraction order by using an AO cell made of the TeO2 single crystal. To explain this effect, a three-dimensional model of AO interaction is proposed, which takes into account the angular selectivity of diffraction both in the plane of Bragg scattering and in the plane orthogonal to it.

  13. Quantitative characterization of edge enhancement in phase contrast x-ray imaging.

    PubMed

    Monnin, P; Bulling, S; Hoszowska, J; Valley, J F; Meuli, R; Verdun, F R

    2004-06-01

    The aim of this study was to model the edge enhancement effect in in-line holography phase contrast imaging. A simple analytical approach was used to quantify refraction and interference contrasts in terms of beam energy and imaging geometry. The model was applied to predict the peak intensity and frequency of the edge enhancement for images of cylindrical fibers. The calculations were compared with measurements, and the relationship between the spatial resolution of the detector and the amplitude of the phase contrast signal was investigated. Calculations using the analytical model were in good agreement with experimental results for nylon, aluminum and copper wires of 50 to 240 microm diameter, and with numerical simulations based on Fresnel-Kirchhoff theory. A relationship between the defocusing distance and the pixel size of the image detector was established. This analytical model is a useful tool for optimizing imaging parameters in phase contrast in-line holography, including defocusing distance, detector resolution and beam energy.

  14. Discrimination methods of biological contamination on fresh-cut lettuce based on VNIR and NIR hyperspectral imaging

    USDA-ARS?s Scientific Manuscript database

    Multispectral imaging algorithms were developed using visible-near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging (HSI) techniques to detect worms on fresh-cut lettuce. The optimal wavebands that detect worm on fresh-cut lettuce for each type of HSI were investigated using the one-way...

  15. Penalized likelihood PET image reconstruction using patch-based edge-preserving regularization.

    PubMed

    Wang, Guobao; Qi, Jinyi

    2012-12-01

    Iterative image reconstruction for positron emission tomography (PET) can improve image quality by using spatial regularization that penalizes image intensity difference between neighboring pixels. The most commonly used quadratic penalty often oversmoothes edges and fine features in reconstructed images. Nonquadratic penalties can preserve edges but often introduce piece-wise constant blocky artifacts and the results are also sensitive to the hyper-parameter that controls the shape of the penalty function. This paper presents a patch-based regularization for iterative image reconstruction that uses neighborhood patches instead of individual pixels in computing the nonquadratic penalty. The new regularization is more robust than the conventional pixel-based regularization in differentiating sharp edges from random fluctuations due to noise. An optimization transfer algorithm is developed for the penalized maximum likelihood estimation. Each iteration of the algorithm can be implemented in three simple steps: an EM-like image update, an image smoothing and a pixel-by-pixel image fusion. Computer simulations show that the proposed patch-based regularization can achieve higher contrast recovery for small objects without increasing background variation compared with the quadratic regularization. The reconstruction is also more robust to the hyper-parameter than conventional pixel-based nonquadratic regularizations. The proposed regularization method has been applied to real 3-D PET data.

  16. Efficient postprocessing scheme for block-coded images based on multiscale edge detection

    NASA Astrophysics Data System (ADS)

    Wu, Shuanhu; Yan, Hong; Tan, Zheng

    2001-09-01

    The block discrete cosine transform (BDCT) is the most widely used technique for the compression of both still and moving images, a major problem related with the BDCT techniques is that the decoded images, especially at low bit rate, exhibit visually annoying blocking effects. In this paper, based on Mallets multiscale edge detection, we proposed an efficient deblocking algorithm to further improved the coding performance. The advantage of our algorithm is that it can efficiently preserve texture structure in the original decompressed images. Our method is similar to that of Z. Xiong's, where the Z.Xiong's method is not suitable for images with a large portion of texture; for instance, the Barbara Image. The difference of our method and the Z.Xiong's is that our method adopted a new thresholding scheme for multi-scale edge detection instead of exploiting cross-scale correlation for edge detection. Numerical experiment results show that our scheme not only outperforms Z.Xiong's for various images in the case of the same computational complexity, but also preserve texture structure in the decompressed images at the same time. Compared with the best iterative-based method (POCS) reported in the literature, our algorithm can achieve the same peak signal-to-noise ratio (PSNR) improvement and give visually very pleasing images as well.

  17. On the Edge

    NASA Image and Video Library

    2015-02-04

    In today's image, Mercury's horizon cuts a striking edge against the stark blackness of space. On the right, sunlight harshly brings the landscape into relief while on the left, the surface is shrouded in the darkness of night. This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere. Date acquired: January 20, 2015 Image Mission Elapsed Time (MET): 64084239 Image ID: 7831084 Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS) WAC filter: 7 (748 nanometers) Center Latitude: -54.45° Center Longitude: 90.52° E Center Resolution: 401 meters/pixel http://photojournal.jpl.nasa.gov/catalog/PIA19192

  18. Imaging the Impact of Proton Irradiation on Edge Terminations in Vertical GaN pin Diodes

    DOE PAGES

    Collins, Kimberlee C.; King, Michael P.; Dickerson, Jeramy R.; ...

    2017-05-29

    Devices based on GaN have shown great promise for high power electronics, including their potential use as radiation tolerant components. An important step to realizing high power diodes is the design and implementation of an edge termination to mitigate field crowding, which can lead to premature breakdown. However, little is known about the effects of radiation on edge termination functionality. We experimentally examine the effects of proton irradiation on multiple field ring edge terminations in high power vertical GaN pin diodes using in operando imaging with electron beam induced current (EBIC). We find that exposure to proton irradiation influences fieldmore » spreading in the edge termination as well as carrier transport near the anode. By using depth-dependent EBIC measurements of hole diffusion length in homoepitaxial n-GaN we demonstrate that the carrier transport effect is due to a reduction in hole diffusion length following proton irradiation.« less

  19. Face recognition via edge-based Gabor feature representation for plastic surgery-altered images

    NASA Astrophysics Data System (ADS)

    Chude-Olisah, Chollette C.; Sulong, Ghazali; Chude-Okonkwo, Uche A. K.; Hashim, Siti Z. M.

    2014-12-01

    Plastic surgery procedures on the face introduce skin texture variations between images of the same person (intra-subject), thereby making the task of face recognition more difficult than in normal scenario. Usually, in contemporary face recognition systems, the original gray-level face image is used as input to the Gabor descriptor, which translates to encoding some texture properties of the face image. The texture-encoding process significantly degrades the performance of such systems in the case of plastic surgery due to the presence of surgically induced intra-subject variations. Based on the proposition that the shape of significant facial components such as eyes, nose, eyebrow, and mouth remains unchanged after plastic surgery, this paper employs an edge-based Gabor feature representation approach for the recognition of surgically altered face images. We use the edge information, which is dependent on the shapes of the significant facial components, to address the plastic surgery-induced texture variation problems. To ensure that the significant facial components represent useful edge information with little or no false edges, a simple illumination normalization technique is proposed for preprocessing. Gabor wavelet is applied to the edge image to accentuate on the uniqueness of the significant facial components for discriminating among different subjects. The performance of the proposed method is evaluated on the Georgia Tech (GT) and the Labeled Faces in the Wild (LFW) databases with illumination and expression problems, and the plastic surgery database with texture changes. Results show that the proposed edge-based Gabor feature representation approach is robust against plastic surgery-induced face variations amidst expression and illumination problems and outperforms the existing plastic surgery face recognition methods reported in the literature.

  20. Finite element modelling for the investigation of edge effect in acoustic micro imaging of microelectronic packages

    NASA Astrophysics Data System (ADS)

    Shen Lee, Chean; Zhang, Guang-Ming; Harvey, David M.; Ma, Hong-Wei; Braden, Derek R.

    2016-02-01

    In acoustic micro imaging of microelectronic packages, edge effect is often presented as artifacts of C-scan images, which may potentially obscure the detection of defects such as cracks and voids in the solder joints. The cause of edge effect is debatable. In this paper, a 2D finite element model is developed on the basis of acoustic micro imaging of a flip-chip package using a 230 MHz focused transducer to investigate acoustic propagation inside the package in attempt to elucidate the fundamental mechanism that causes the edge effect. A virtual transducer is designed in the finite element model to reduce the coupling fluid domain, and its performance is characterised against the physical transducer specification. The numerical results showed that the under bump metallization (UBM) structure inside the package has a significant impact on the edge effect. Simulated wavefields also showed that the edge effect is mainly attributed to the horizontal scatter, which is observed in the interface of silicon die-to-the outer radius of solder bump. The horizontal scatter occurs even for a flip-chip package without the UBM structure.

  1. A quantitative study of the orientation bias of some edge detector schemes. [in ERTS satellite image processing

    NASA Technical Reports Server (NTRS)

    Deutsch, E. S.; Fram, J. R.

    1978-01-01

    The article discusses the orientational biases of various edge detection methods. On the basis of ERTS satellite images, three methods are compared: (1) Heuckel's local visual operator (1973), (2) Macleod's Gaussian edge mask detector (1972), and (3) Rosenfeld's local difference calculations (1971). The results yielded by these techniques are compared to the method for quantifying edge detector performance developed by Herskovits (1970).

  2. EVolution: an edge-based variational method for non-rigid multi-modal image registration

    NASA Astrophysics Data System (ADS)

    de Senneville, B. Denis; Zachiu, C.; Ries, M.; Moonen, C.

    2016-10-01

    Image registration is part of a large variety of medical applications including diagnosis, monitoring disease progression and/or treatment effectiveness and, more recently, therapy guidance. Such applications usually involve several imaging modalities such as ultrasound, computed tomography, positron emission tomography, x-ray or magnetic resonance imaging, either separately or combined. In the current work, we propose a non-rigid multi-modal registration method (namely EVolution: an edge-based variational method for non-rigid multi-modal image registration) that aims at maximizing edge alignment between the images being registered. The proposed algorithm requires only contrasts between physiological tissues, preferably present in both image modalities, and assumes deformable/elastic tissues. Given both is shown to be well suitable for non-rigid co-registration across different image types/contrasts (T1/T2) as well as different modalities (CT/MRI). This is achieved using a variational scheme that provides a fast algorithm with a low number of control parameters. Results obtained on an annotated CT data set were comparable to the ones provided by state-of-the-art multi-modal image registration algorithms, for all tested experimental conditions (image pre-filtering, image intensity variation, noise perturbation). Moreover, we demonstrate that, compared to existing approaches, our method possesses increased robustness to transient structures (i.e. that are only present in some of the images).

  3. EVolution: an edge-based variational method for non-rigid multi-modal image registration.

    PubMed

    Denis de Senneville, B; Zachiu, C; Ries, M; Moonen, C

    2016-10-21

    Image registration is part of a large variety of medical applications including diagnosis, monitoring disease progression and/or treatment effectiveness and, more recently, therapy guidance. Such applications usually involve several imaging modalities such as ultrasound, computed tomography, positron emission tomography, x-ray or magnetic resonance imaging, either separately or combined. In the current work, we propose a non-rigid multi-modal registration method (namely EVolution: an edge-based variational method for non-rigid multi-modal image registration) that aims at maximizing edge alignment between the images being registered. The proposed algorithm requires only contrasts between physiological tissues, preferably present in both image modalities, and assumes deformable/elastic tissues. Given both is shown to be well suitable for non-rigid co-registration across different image types/contrasts (T1/T2) as well as different modalities (CT/MRI). This is achieved using a variational scheme that provides a fast algorithm with a low number of control parameters. Results obtained on an annotated CT data set were comparable to the ones provided by state-of-the-art multi-modal image registration algorithms, for all tested experimental conditions (image pre-filtering, image intensity variation, noise perturbation). Moreover, we demonstrate that, compared to existing approaches, our method possesses increased robustness to transient structures (i.e. that are only present in some of the images).

  4. Edge-detected detail enhancement through synthesis of multi-light images

    NASA Astrophysics Data System (ADS)

    Zheng, Jinghong; Li, Zhengguo; Rahardja, Susanto; Yao, Susu

    2010-01-01

    A collaborative image processing method is proposed to enhance the shape and details of a scene through synthesizing a set of multi-light images that capture a scene with fixed view-point but various lighting positions. A very challenging problem is to remove the artifacts due to shadow edges from the synthesized image. To address this problem, a simple Sobel filter based method is provided by utilizing the feature of multi-light images in which the shadow edges are usually not overlapped. A detail layer that contains the details of all images is firstly constructed by using a gradient domain method and a quadratic filter. Then a base layer is produced by using only one input image. The detail layer is finally added to the base layer to produce the desired detail enhanced image. Using this method, the details lost in the shadow of original input image can be reproduced by the details of other images and the sense of depth is preserved well in the synthesized image. Interactivities are also provided for users to adjust the appearance of the detail enhanced image according to their preferences.

  5. Edge pixel response studies of edgeless silicon sensor technology for pixellated imaging detectors

    NASA Astrophysics Data System (ADS)

    Maneuski, D.; Bates, R.; Blue, A.; Buttar, C.; Doonan, K.; Eklund, L.; Gimenez, E. N.; Hynds, D.; Kachkanov, S.; Kalliopuska, J.; McMullen, T.; O'Shea, V.; Tartoni, N.; Plackett, R.; Vahanen, S.; Wraight, K.

    2015-03-01

    Silicon sensor technologies with reduced dead area at the sensor's perimeter are under development at a number of institutes. Several fabrication methods for sensors which are sensitive close to the physical edge of the device are under investigation utilising techniques such as active-edges, passivated edges and current-terminating rings. Such technologies offer the goal of a seamlessly tiled detection surface with minimum dead space between the individual modules. In order to quantify the performance of different geometries and different bulk and implant types, characterisation of several sensors fabricated using active-edge technology were performed at the B16 beam line of the Diamond Light Source. The sensors were fabricated by VTT and bump-bonded to Timepix ROICs. They were 100 and 200 μ m thick sensors, with the last pixel-to-edge distance of either 50 or 100 μ m. The sensors were fabricated as either n-on-n or n-on-p type devices. Using 15 keV monochromatic X-rays with a beam spot of 2.5 μ m, the performance at the outer edge and corners pixels of the sensors was evaluated at three bias voltages. The results indicate a significant change in the charge collection properties between the edge and 5th (up to 275 μ m) from edge pixel for the 200 μ m thick n-on-n sensor. The edge pixel performance of the 100 μ m thick n-on-p sensors is affected only for the last two pixels (up to 110 μ m) subject to biasing conditions. Imaging characteristics of all sensor types investigated are stable over time and the non-uniformities can be minimised by flat-field corrections. The results from the synchrotron tests combined with lab measurements are presented along with an explanation of the observed effects.

  6. Edge-enhanced imaging obtained with very broad energy band x-rays

    SciTech Connect

    Taibi, A.; Cardarelli, P.; Di Domenico, G.; Marziani, M.; Gambaccini, M.; Hanashima, T.; Yamada, H.

    2010-04-05

    We demonstrate both theoretically and experimentally that edge-enhancement effects are produced when objects, in contact with the x-ray detector, are imaged by using very broad x-ray spectra. Radiographs of thin Al objects have been obtained with a table-top synchrotron source which generates x-rays in the energy range from a few kilo-electron-volts up to 6 MeV. Edge-enhancement effects arise from the combination of x-ray absorption (kilo-electron-volt part of the spectrum) and secondary particle emission (mega-electron-volt part of the spectrum) within the sample. The exact contribution of absorption and emission profiles in the edge-enhanced images has been calculated via Monte Carlo simulation.

  7. Direct imaging of topological edge states in cold-atom systems

    PubMed Central

    Goldman, Nathan; Dalibard, Jean; Dauphin, Alexandre; Gerbier, Fabrice; Lewenstein, Maciej; Zoller, Peter; Spielman, Ian B.

    2013-01-01

    Detecting topological order in cold-atom experiments is an ongoing challenge, the resolution of which offers novel perspectives on topological matter. In material systems, unambiguous signatures of topological order exist for topological insulators and quantum Hall devices. In quantum Hall systems, the quantized conductivity and the associated robust propagating edge modes—guaranteed by the existence of nontrivial topological invariants—have been observed through transport and spectroscopy measurements. Here, we show that optical-lattice-based experiments can be tailored to directly visualize the propagation of topological edge modes. Our method is rooted in the unique capability for initially shaping the atomic gas and imaging its time evolution after suddenly removing the shaping potentials. Our scheme, applicable to an assortment of atomic topological phases, provides a method for imaging the dynamics of topological edge modes, directly revealing their angular velocity and spin structure. PMID:23569266

  8. Direct imaging of topological edge states in cold-atom systems.

    PubMed

    Goldman, Nathan; Dalibard, Jean; Dauphin, Alexandre; Gerbier, Fabrice; Lewenstein, Maciej; Zoller, Peter; Spielman, Ian B

    2013-04-23

    Detecting topological order in cold-atom experiments is an ongoing challenge, the resolution of which offers novel perspectives on topological matter. In material systems, unambiguous signatures of topological order exist for topological insulators and quantum Hall devices. In quantum Hall systems, the quantized conductivity and the associated robust propagating edge modes--guaranteed by the existence of nontrivial topological invariants--have been observed through transport and spectroscopy measurements. Here, we show that optical-lattice-based experiments can be tailored to directly visualize the propagation of topological edge modes. Our method is rooted in the unique capability for initially shaping the atomic gas and imaging its time evolution after suddenly removing the shaping potentials. Our scheme, applicable to an assortment of atomic topological phases, provides a method for imaging the dynamics of topological edge modes, directly revealing their angular velocity and spin structure.

  9. [Deciphering the "ugly duckling", but escaping the "telly belly". Exploratory algorithm of the diagnostic cutting edge of melanoma].

    PubMed

    Quatresooz, P; Piérard, G E; Piérard-Franchimont, C

    2010-04-01

    In a manichean ideal, one expects unreservedly a clear-cut distinction between benign melanocytic neoplasms and the malignant ones. Such a distinction is commonly established by a clinico-pathologic confrontation for the majority of neoplasms. However, the boundaries may be blurred and uncertain for some lesions. We present an exploratory clinicopathologic algorithm of the border area between seemingly benign and seemingly malignant melanocytic neoplasms. The concept of a group of neoplasms called skin melanocytomas shed some light on such quandaries where the risk of misdiagnosis is quite high.

  10. A novel edge-parameter analysis approach of blur identification for image de-blurring application

    NASA Astrophysics Data System (ADS)

    He, Jinping; Gao, Kun; Ni, Guoqiang

    2008-12-01

    In this paper, a novel edge-parameter analysis method of the blu' identification based on the single-threshold Pulse Coupled Neural Networks (PCNN) model is proposed for image de-blurring application. It suits to the identification of the horizontal linear motion blur. This new identification method not only improves on the traditional PCNN, but also uses the normalized local entropy. On the one hand, the new method uses the local entropy which is normalized between 0 and 255. On the other hand, a new model called the single-threshold PCNN is proposed in this article. Comparing with the traditional PCNN, the improved one calculates faster, and it is more sensitive to the image edges. The experimental results which are obtained from the different images and the same image with the different resolution show that the new algorithm is very effective and the curve is the very steady graph. The identification precision is about 4 to 30 pixels.

  11. Real time /ital K/-edge subtraction x-ray imaging

    SciTech Connect

    Fukagawa, H.; Noda, C.; Suzuki, Y.; Hasegawa, S.; Ando, M.; Hyodo, K.; Nishimura, K.; Akisada, M.; Takenaka, E.; Hosaka, R.; and others

    1989-07-01

    This paper describes an x-ray /ital K/-edge subtraction television system for noninvasive angiography utilizing synchrotron radiation. The phantom, including contrast material (iodine), is irradiated by monochromatized dual-energy x-ray flux, alternately, using a high speed monochromator. The monochromator consists of a silicon crystal plate vibrating at 15 Hz so that the phantom is irradiated by the x-ray flux of 150 eV above and below the /ital K/-edge photon energy of iodine, 15 times per second. As an x-ray detector, TV cameras optically coupled to an x-ray image intensifier are used and the video signal is processed to display the subtraction image of pairs of successive images in real time. This system was fully implemented and moving phantoms were examined. Both the time interval between the energy change and the exposure time of each image has been shortened to 2 ms.

  12. Satellite Image Edge Detection for Population Distribution Pattern Identification using Levelset with Morphological Filtering Process

    NASA Astrophysics Data System (ADS)

    Harsiti; Munandar, T. A.; Suhendar, A.; Abdullah, A. G.; Rohendi, D.

    2017-03-01

    Population distribution pattern is directly related with economic gap of a region. Analysis of population distribution pattern is usually performed by studying statistical data on population. This study aimed to analyze population distribution pattern using image analysis concept, i.e. using satellite images. Levelset and morphological image filtering methods were used to analyze images to see distribution pattern. The research result showed that Levelset and morphological image filtering could remove a lot of noises in analysis result images and form object edge contours very clearly. The detected object contours were used as references to recognize population distribution pattern based on satellite image analysis. The pattern made based on the research result didn’t show optimal result because Levelset performed image segmentation based on the contours of the analyzed objects. Other segmentation methods should be combined with it to produce clearer population distribution pattern.

  13. [The analysis and comparison of different edge detection algorithms in ultrasound B-scan images].

    PubMed

    Zhang, Luo-ping; Yang, Bo-yuan; Wang, Chun-hong

    2006-05-01

    In this paper, some familiar algorithms of edge detection in ultrasound B-scan images are analyzed and studied. The results show that Sobel, Prewitt and Laplacian operators are sensitive to noise, Hough transform adapts to the whole detection, while LoG algorithm's average is zero and it couldn't change the whole dynamic area. Accordingly LoG algorithm is preferable.

  14. X-ray Phase Imaging Microscopy with Two-Dimensional Knife-Edge Filters

    NASA Astrophysics Data System (ADS)

    Choi, Jaeho; Park, Yong-Sung

    2012-04-01

    A novel scheme of X-ray differential phase imaging was implemented with an array source and a two-dimensional Foucault knife-edge (2DFK). A pinhole array lens was employed to manipulate the X-ray beam on the Fourier space. An emerging biaxial scanning procedure was also demonstrated with the periodic 2DFK. The differential phase images (DPIs) of the midrib in a leaf of a rose bush were visualized to verify the phase imaging of biological specimens by the proposed method. It also has features of depicting multiple-stack phase images, and rendering morphological DPIs, because it acquires pure phase information.

  15. Edge-enhanced imaging with polyvinyl alcohol/acrylamide photopolymer gratings.

    PubMed

    Márquez, Andrés; Neipp, Cristian; Beléndez, Augusto; Gallego, Sergi; Ortuño, Manuel; Pascual, Inmaculada

    2003-09-01

    We demonstrate edge-enhanced imaging produced by volume phase gratings recorded on a polyvinyl alcohol/acrylamide photopolymer. Bragg diffraction, exhibited by volume gratings, modifies the impulse response of the imaging system, facilitating spatial filtering operations with no need for a physical Fourier plane. We demonstrate that Kogelnik's coupled-wave theory can be used to calculate the transfer function for the transmitted and the diffracted orders. The experimental and simulated results agree, and they demonstrate the feasibility of our proposal.

  16. Edge detection and reduction of brightness of students' bubble form images

    NASA Astrophysics Data System (ADS)

    Ilkin, Sümeyya; Şahin, Suhap

    2015-03-01

    Optical Mark Recognition (OMR) is a traditional data input technique and an important human computer interaction technique which is widely used in education testing. This paper proposes a new idea for grading multiple-choice test which is based on a camera on smartphone. The system key techniques and relevant implementations, which include the image scan, edge detection and reduction of brightness on colorful bubble form images, are presented.

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

    SciTech Connect

    Tsantis, Stavros; Spiliopoulos, Stavros; Karnabatidis, Dimitrios; Skouroliakou, Aikaterini; Hazle, John D.; Kagadis, George C. E-mail: George.Kagadis@med.upatras.gr

    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 new wavelet

  18. Fibre laser cutting stainless steel: Fluid dynamics and cut front morphology

    NASA Astrophysics Data System (ADS)

    Pocorni, Jetro; Powell, John; Deichsel, Eckard; Frostevarg, Jan; Kaplan, Alexander F. H.

    2017-01-01

    In this paper the morphology of the laser cut front generated by fibre lasers was investigated by observation of the 'frozen' cut front, additionally high speed imaging (HSI) was employed to study the fluid dynamics on the cut front while cutting. During laser cutting the morphology and flow properties of the melt film on the cut front affect cut quality parameters such as cut edge roughness and dross (residual melt attached to the bottom of the cut edge). HSI observation of melt flow down a laser cutting front using standard cutting parameters is experimentally problematic because the cut front is narrow and surrounded by the kerf walls. To compensate for this, artificial parameters are usually chosen to obtain wide cut fronts which are unrepresentative of the actual industrial process. This paper presents a new experimental cutting geometry which permits HSI of the laser cut front using standard, commercial parameters. These results suggest that the cut front produced when cutting medium section (10 mm thick) stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered by a thin layer of liquid. HSI observation and theoretical analysis reveal that under these conditions the humps move down the cut front at an average speed of approximately 0.4 m/s while the covering liquid flows at an average speed of approximately 1.1 m/s, with an average melt depth at the bottom of the cut zone of approximately 0.17 mm.

  19. Gas Puff Imaging Studies of Tokamak Edge Physics in the National Spherical Torus Experiment

    NASA Astrophysics Data System (ADS)

    Sechrest, Yancey

    In order to be viable, Next-step fusion devices must overcome two pressing problems: they must be able to achieve high levels of confinement while also handling potentially damaging heat loads on material surfaces. The study of plasma edge physics promises solutions to both problems because the plasma edge, being the boundary between confined and unconfined regions, plays a key role in determining the global confinement and the plasma interaction with material surfaces (e.g. edge transport barriers, pedestal evolution, and edge localized modes). However, the steep gradients in density and temperature in the plasma edge that drive strong fluctuations in plasma parameters require measurements of fluctuations with high spatial and temporal resolution. By measuring drift scale (kyrhos < 2) fluctuations for frequencies less than ˜ 200 kHz, Gas Puff Imaging (GPI) meets these requirements while providing two-dimensional coverage at a large number of measurement locations. This dissertation presents GPI studies of transitions from low to high confinement regimes (L-H transitions) and Edge Localized Modes (ELMs). In 2010, a study of L-H transitions with the GPI diagnostic revealed quasi-periodic reductions in the scrape-off-layer turbulence levels during the 30 ms preceding the transition. The two-dimensional flow fields for these "quiet-periods", estimated from the GPI data by a pattern-matching velocimetry technique, exhibit intriguing similarity with the Drift Wave - Zonal Flow paradigm, a leading candidate in explaining L-H transitions. Following this study, a survey of GPI data from RF heated H-mode plasmas near the L-H power threshold identified short-lived, coherent oscillations in edge emission preceding the ELM crash. These observations provide detailed two-dimensional dynamics of the growth, filamentation, and crash of the ELM event, which could improve our understanding through comparison with nonlinear simulation. Cross diagnostic comparisons of GPI and Beam

  20. K-edge ratio method for identification of multiple nanoparticulate contrast agents by spectral CT imaging

    PubMed Central

    Ghadiri, H; Ay, M R; Shiran, M B; Soltanian-Zadeh, H

    2013-01-01

    Objective: Recently introduced energy-sensitive X-ray CT makes it feasible to discriminate different nanoparticulate contrast materials. The purpose of this work is to present a K-edge ratio method for differentiating multiple simultaneous contrast agents using spectral CT. Methods: The ratio of two images relevant to energy bins straddling the K-edge of the materials is calculated using an analytic CT simulator. In the resulting parametric map, the selected contrast agent regions can be identified using a thresholding algorithm. The K-edge ratio algorithm is applied to spectral images of simulated phantoms to identify and differentiate up to four simultaneous and targeted CT contrast agents. Results: We show that different combinations of simultaneous CT contrast agents can be identified by the proposed K-edge ratio method when energy-sensitive CT is used. In the K-edge parametric maps, the pixel values for biological tissues and contrast agents reach a maximum of 0.95, whereas for the selected contrast agents, the pixel values are larger than 1.10. The number of contrast agents that can be discriminated is limited owing to photon starvation. For reliable material discrimination, minimum photon counts corresponding to 140 kVp, 100 mAs and 5-mm slice thickness must be used. Conclusion: The proposed K-edge ratio method is a straightforward and fast method for identification and discrimination of multiple simultaneous CT contrast agents. Advances in knowledge: A new spectral CT-based algorithm is proposed which provides a new concept of molecular CT imaging by non-iteratively identifying multiple contrast agents when they are simultaneously targeting different organs. PMID:23934964

  1. Edge-preserving image compression for magnetic-resonance images using dynamic associative neural networks (DANN)-based neural networks

    NASA Astrophysics Data System (ADS)

    Wan, Tat C.; Kabuka, Mansur R.

    1994-05-01

    With the tremendous growth in imaging applications and the development of filmless radiology, the need for compression techniques that can achieve high compression ratios with user specified distortion rates becomes necessary. Boundaries and edges in the tissue structures are vital for detection of lesions and tumors, which in turn requires the preservation of edges in the image. The proposed edge preserving image compressor (EPIC) combines lossless compression of edges with neural network compression techniques based on dynamic associative neural networks (DANN), to provide high compression ratios with user specified distortion rates in an adaptive compression system well-suited to parallel implementations. Improvements to DANN-based training through the use of a variance classifier for controlling a bank of neural networks speed convergence and allow the use of higher compression ratios for `simple' patterns. The adaptation and generalization capabilities inherent in EPIC also facilitate progressive transmission of images through varying the number of quantization levels used to represent compressed patterns. Average compression ratios of 7.51:1 with an averaged average mean squared error of 0.0147 were achieved.

  2. Defect detection on images using multiple reference images: solving a binary labeling problem using graph-cuts algorithm

    NASA Astrophysics Data System (ADS)

    Lee, Janghee; Yoo, Suk I.

    2012-07-01

    We present a new formulation to solve a defect detection problem on images using multiple reference images. The reference images are defect-free images obtained from the same position of other products. The defect detection problem is reformulated as a binary labeling problem, where each pixel is labeled with "one" if it contains a defect and with "zero" otherwise. The formulation of the energy function used for the labeling problem is defined. Then, the graph-cuts algorithm is used to obtain the optimal label set minimizing the energy function that becomes the defect detection result. The presented approaches are robust to noises taken from several sources, including image-taking, transmission process, environmental lighting, and pattern variation. It does not suffer from the alignment problem for the conventional comparison methods using references. These approaches are illustrated with real data sets, semiconductor wafer images collected by scanning electron microscope equipment, and compared to other defect detection approach.

  3. Synthetic aperture radar image segmentation based on edge-region active contour model

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Wen, Xianbin; Xu, Haixia; Meng, Qingxia

    2016-07-01

    An energy functional is proposed based on an edge-region active contour model for synthetic aperture radar (SAR) image segmentation. The proposed energy functional not only has a desirable property to process inhomogeneous regions in SAR images, but also shows satisfactory convergence speed. Our proposed energy functional consists of two main energy terms: an edge-region term and a regularization term. The edge-region term is derived from a Gamma model and gradient term model, which can process the speckle noises and drive the motion of the curves toward desired locations. The regularization term is not only able to maintain a desired shape of the evolution curves but also has a strong smoothing curve effect and avoid the occurrence of small, isolated regions in the final segmentation. Finally, the gradient descent flow method is introduced for minimizing our energy functional. A desirable feature of the proposed method is that it is not sensitive to the contour initialization. Compared with other methods, experimental results show that the proposed approach has promising edge detection results on the synthetic and real SAR images.

  4. Edge co-occurrences can account for rapid categorization of natural versus animal images

    NASA Astrophysics Data System (ADS)

    Perrinet, Laurent U.; Bednar, James A.

    2015-06-01

    Making a judgment about the semantic category of a visual scene, such as whether it contains an animal, is typically assumed to involve high-level associative brain areas. Previous explanations require progressively analyzing the scene hierarchically at increasing levels of abstraction, from edge extraction to mid-level object recognition and then object categorization. Here we show that the statistics of edge co-occurrences alone are sufficient to perform a rough yet robust (translation, scale, and rotation invariant) scene categorization. We first extracted the edges from images using a scale-space analysis coupled with a sparse coding algorithm. We then computed the “association field” for different categories (natural, man-made, or containing an animal) by computing the statistics of edge co-occurrences. These differed strongly, with animal images having more curved configurations. We show that this geometry alone is sufficient for categorization, and that the pattern of errors made by humans is consistent with this procedure. Because these statistics could be measured as early as the primary visual cortex, the results challenge widely held assumptions about the flow of computations in the visual system. The results also suggest new algorithms for image classification and signal processing that exploit correlations between low-level structure and the underlying semantic category.

  5. An estimation/correction algorithm for detecting bone edges in CT images.

    PubMed

    Yao, W; Abolmaesumi, P; Greenspan, M; Ellis, R E

    2005-08-01

    The normal direction of the bone contour in computed tomography (CT) images provides important anatomical information and can guide segmentation algorithms. Since various bones in CT images have different sizes, and the intensity values of bone pixels are generally nonuniform and noisy, estimation of the normal direction using a single scale is not reliable. We propose a multiscale approach to estimate the normal direction of bone edges. The reliability of the estimation is calculated from the estimated results and, after re-scaling, the reliability is used to further correct the normal direction. The optimal scale at each point is obtained while estimating the normal direction; this scale is then used in a simple edge detector. Our experimental results have shown that use of this estimated/corrected normal direction improves the segmentation quality by decreasing the number of unexpected edges and discontinuities (gaps) of real contours. The corrected normal direction could also be used in postprocessing to delete false edges. Our segmentation algorithm is automatic, and its performance is evaluated on CT images of the human pelvis, leg, and wrist.

  6. Reduction of blocking artifact based on edge information in discrete cosine transform-coded images

    NASA Astrophysics Data System (ADS)

    Kwon, Goo-Rak; Lama, Ramesh Kumar; Pyun, Jae-Young; Lee, Sang-Woong

    2011-09-01

    We propose new method for the reduction of blocking artifacts present in low bit-rate coded images. This algorithm performs the deblocking operation in two modes that are determined by the number of edge pixels around the block boundary. The number of edge pixels is calculated by applying the Roberts edge filter. An appropriate filtering operation is performed for each mode in both the horizontal and vertical directions. First, when the mode is associated with a smooth region, a strong filtering operation is applied because flat regions are more sensitive to the human visual system. In the second mode, an adaptive low-pass filter that is based on pixel behavior around the block boundaries is applied. This filter reduces the blocking artifact without introducing undesired blurring effects, while the original image edge is preserved. Although the proposed approach is simple and operates in the spatial domain, experimental results show that it improves both the subjective and objective qualities of the coded image with various features.

  7. Prototype of Partial Cutting Tool of Geological Map Images Distributed by Geological Web Map Service

    NASA Astrophysics Data System (ADS)

    Nonogaki, S.; Nemoto, T.

    2014-12-01

    Geological maps and topographical maps play an important role in disaster assessment, resource management, and environmental preservation. These map information have been distributed in accordance with Web services standards such as Web Map Service (WMS) and Web Map Tile Service (WMTS) recently. In this study, a partial cutting tool of geological map images distributed by geological WMTS was implemented with Free and Open Source Software. The tool mainly consists of two functions: display function and cutting function. The former function was implemented using OpenLayers. The latter function was implemented using Geospatial Data Abstraction Library (GDAL). All other small functions were implemented by PHP and Python. As a result, this tool allows not only displaying WMTS layer on web browser but also generating a geological map image of intended area and zoom level. At this moment, available WTMS layers are limited to the ones distributed by WMTS for the Seamless Digital Geological Map of Japan. The geological map image can be saved as GeoTIFF format and WebGL format. GeoTIFF is one of the georeferenced raster formats that is available in many kinds of Geographical Information System. WebGL is useful for confirming a relationship between geology and geography in 3D. In conclusion, the partial cutting tool developed in this study would contribute to create better conditions for promoting utilization of geological information. Future work is to increase the number of available WMTS layers and the types of output file format.

  8. The use of atlas registration and graph cuts for prostate segmentation in magnetic resonance images

    SciTech Connect

    Korsager, Anne Sofie Østergaard, Lasse Riis; Fortunati, Valerio; Lijn, Fedde van der; Niessen, Wiro; Walsum, Theo van; Carl, Jesper

    2015-04-15

    Purpose: An automatic method for 3D prostate segmentation in magnetic resonance (MR) images is presented for planning image-guided radiotherapy treatment of prostate cancer. Methods: A spatial prior based on intersubject atlas registration is combined with organ-specific intensity information in a graph cut segmentation framework. The segmentation is tested on 67 axial T{sub 2}-weighted MR images in a leave-one-out cross validation experiment and compared with both manual reference segmentations and with multiatlas-based segmentations using majority voting atlas fusion. The impact of atlas selection is investigated in both the traditional atlas-based segmentation and the new graph cut method that combines atlas and intensity information in order to improve the segmentation accuracy. Best results were achieved using the method that combines intensity information, shape information, and atlas selection in the graph cut framework. Results: A mean Dice similarity coefficient (DSC) of 0.88 and a mean surface distance (MSD) of 1.45 mm with respect to the manual delineation were achieved. Conclusions: This approaches the interobserver DSC of 0.90 and interobserver MSD 0f 1.15 mm and is comparable to other studies performing prostate segmentation in MR.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  10. Development of KSTAR ECE imaging system for measurement of temperature fluctuations and edge density fluctuations.

    PubMed

    Yun, G S; Lee, W; Choi, M J; Kim, J B; Park, H K; Domier, C W; Tobias, B; Liang, T; Kong, X; Luhmann, N C; Donné, A J H

    2010-10-01

    The ECE imaging (ECEI) diagnostic tested on the TEXTOR tokamak revealed the sawtooth reconnection physics in unprecedented detail, including the first observation of high-field-side crash and collective heat transport [H. K. Park, N. C. Luhmann, Jr., A. J. H. Donné et al., Phys. Rev. Lett. 96, 195003 (2006)]. An improved ECEI system capable of visualizing both high- and low-field sides simultaneously with considerably better spatial coverage has been developed for the KSTAR tokamak in order to capture the full picture of core MHD dynamics. Direct 2D imaging of other MHD phenomena such as tearing modes, edge localized modes, and even Alfvén eigenmodes is expected to be feasible. Use of ECE images of the optically thin edge region to recover 2D electron density changes during L/H mode transitions is also envisioned, providing powerful information about the underlying physics. The influence of density fluctuations on optically thin ECE is discussed.

  11. Development of KSTAR ECE imaging system for measurement of temperature fluctuations and edge density fluctuations

    SciTech Connect

    Yun, G. S.; Lee, W.; Choi, M. J.; Kim, J. B.; Park, H. K.; Domier, C. W.; Tobias, B.; Liang, T.; Kong, X.; Luhmann, N. C. Jr.; Donne, A. J. H.

    2010-10-15

    The ECE imaging (ECEI) diagnostic tested on the TEXTOR tokamak revealed the sawtooth reconnection physics in unprecedented detail, including the first observation of high-field-side crash and collective heat transport [H. K. Park, N. C. Luhmann, Jr., A. J. H. Donneet al., Phys. Rev. Lett. 96, 195003 (2006)]. An improved ECEI system capable of visualizing both high- and low-field sides simultaneously with considerably better spatial coverage has been developed for the KSTAR tokamak in order to capture the full picture of core MHD dynamics. Direct 2D imaging of other MHD phenomena such as tearing modes, edge localized modes, and even Alfven eigenmodes is expected to be feasible. Use of ECE images of the optically thin edge region to recover 2D electron density changes during L/H mode transitions is also envisioned, providing powerful information about the underlying physics. The influence of density fluctuations on optically thin ECE is discussed.

  12. HST/WFC3 Imaging and Multi-Wavelength Characterization of Edge-On Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Gould, Carolina; Duchene, Gaspard; Stapelfeldt, Karl R.; Menard, Francois; Padgett, Deborah; Perrin, Marshall D.; Pinte, Christophe; Wolff, Schuyler

    2016-06-01

    Edge-on views of protoplanetary disk systems provide a unique observing opportunity to assess the vertical dust structure of the disk, an opportunity that is not possible at any other viewing angle due to projection effects and the acute brightness of the central star. Comparing high-resolution scattered light images of edge-on disks with synthetic images from radiative transfer modeling is a powerful approach to constrain the disk mass, structure and dust content, although analyses based on single-wavelength images lead to ambiguous conclusions. In order to resolve these ambiguities, and to probe the most tenuous regions at high elevation above the disk midplane, it is critical to obtain high-resolution images of such objects at the shortest possible wavelengths, where dust opacity is maximized. In this contribution, we present new WFC3 F475W Hubble Space Telescope images of 6 known edge-on protoplanetary disks. We produced color maps across the visible band to identify and characterize wavelength-dependent properties of these disks. In turn, these allow us to differentiate features that are related to the dust properties (opacity, scattering phase function) from those tracing the physical structure of the disk (in particular its vertical density profile). By probing a diverse set of disks with a uniform approach, we will be able to probe possible signs of evolution in this critical stage of planet formation.

  13. Efficient registration of multitemporal and multisensor aerial images based on alignment of nonparametric edge features

    NASA Astrophysics Data System (ADS)

    Makrogiannis, Sokratis; Bourbakis, Nikolaos G.

    2010-01-01

    The topic of aerial image registration attracts considerable interest within the imaging research community due to its significance for several applications, including change detection, sensor fusion, and topographic mapping. Our interest is focused on finding the optimal transformation between two aerial images that depict the same visual scene in the presence of pronounced spatial, temporal, and sensor variations. We first introduce a stochastic edge estimation process suitable for geometric shape-based registration, which we also compare to intensity-based registration. Furthermore, we propose an objective function that weights the L2 distances of the edge estimates by the feature points' energy, which we denote by sum of normalized squared differences and compare to standard objective functions, such as mutual information and the sum of absolute centered differences. In the optimization stage, we employ a genetic algorithm scheme in a multiscale image representation scheme to enhance the registration accuracy and reduce the computational load. Our experimental tests, measuring registration accuracy, rate of convergence, and statistical properties of registration errors, suggest that the proposed edge-based representation and objective function in conjunction with genetic algorithm optimization are capable of addressing several forms of imaging variations and producing encouraging registration results.

  14. Parallel algorithm for determining motion vectors in ice floe images by matching edge features

    NASA Technical Reports Server (NTRS)

    Manohar, M.; Ramapriyan, H. K.; Strong, J. P.

    1988-01-01

    A parallel algorithm is described to determine motion vectors of ice floes using time sequences of images of the Arctic ocean obtained from the Synthetic Aperture Radar (SAR) instrument flown on-board the SEASAT spacecraft. Researchers describe a parallel algorithm which is implemented on the MPP for locating corresponding objects based on their translationally and rotationally invariant features. The algorithm first approximates the edges in the images by polygons or sets of connected straight-line segments. Each such edge structure is then reduced to a seed point. Associated with each seed point are the descriptions (lengths, orientations and sequence numbers) of the lines constituting the corresponding edge structure. A parallel matching algorithm is used to match packed arrays of such descriptions to identify corresponding seed points in the two images. The matching algorithm is designed such that fragmentation and merging of ice floes are taken into account by accepting partial matches. The technique has been demonstrated to work on synthetic test patterns and real image pairs from SEASAT in times ranging from .5 to 0.7 seconds for 128 x 128 images.

  15. Computed tomography imaging of Medpor: Graph-cut algorithm and its accuracy.

    PubMed

    Liu, Xiao-jing; Chen, Li; Song, Wei; Guo, Chuan-bin; Yu, Guang-yan

    2012-05-01

    Porous polyethylene has become a popular alloplastic material for maxillofacial reconstruction. Despite its benefits, this material is radiolucent on conventional radiography. Computed tomography of traditional graphic segmentation based on gray levels was reported by a few authors, but the accuracy has not been described. The aim of this study was to image this material using segmentation based on Graph-cut algorithm. Another object was to compare accuracy of 2 algorithms. Between 2005 and 2010, 15 patients (12 females) participated in the study. Computed tomography was used for image acquisition. Graphic segmentation based on gray level involved use of the software OsiriX. Stroke-based specification for user interaction and Graph-cut segmentation involved a self-developed module. The accuracy of both segmentation algorithms was tested by comparing the volume of reconstructed Medpor with the actual volume measured by the draining method during surgery. Twenty-seven comparisons of the computed and actual volumes were gained. Linear regression was done between reconstructed and real volume. For the volume of Graph-cut algorithm, the regression equation was T = -0.19425 + 1.02692S; the difference between the population intercept and zero was not significant (t = -0.83, P = 0.4172). For the volume of gray-level algorithm, the regression equation was T = -1.15282 + 1.14101S; the difference between the population intercept and zero was significant (t = -3.04, P = 0.0055).These results demonstrated porous polyethylene can be well defined by computed tomography segmentation with Graph-cut and gray-level algorithms. Graph-cut algorithm has a better accuracy compared with that of gray-level algorithm.

  16. CUTTING AND WEDGING JACKET REMOVER

    DOEpatents

    Freedman, M.; Raynor, S.

    1959-04-01

    A tool is presented for stripping cladded jackets from fissionable fuel elements. The tool is a tube which fits closely around the jacket and which has two cutting edges at opposite sides of one end. These cutting edges are adjusted to penetrate only the jacket so that by moving the edges downward the jacket is cut into two pieces.

  17. Infrared image enhancement based on the edge detection and mathematical morphology

    NASA Astrophysics Data System (ADS)

    Zhang, Linlin; Zhao, Yuejin; Dong, Liquan; Liu, Xiaohua; Yu, Xiaomei; Hui, Mei; Chu, Xuhong; Gong, Cheng

    2010-11-01

    The development of the un-cooled infrared imaging technology from military necessity. At present, It is widely applied in industrial, medicine, scientific and technological research and so on. The infrared radiation temperature distribution of the measured object's surface can be observed visually. The collection of infrared images from our laboratory has following characteristics: Strong spatial correlation, Low contrast , Poor visual effect; Without color or shadows because of gray image , and has low resolution; Low definition compare to the visible light image; Many kinds of noise are brought by the random disturbances of the external environment. Digital image processing are widely applied in many areas, it can now be studied up close and in detail in many research field. It has become one kind of important means of the human visual continuation. Traditional methods for image enhancement cannot capture the geometric information of images and tend to amplify noise. In order to remove noise and improve visual effect. Meanwhile, To overcome the above enhancement issues. The mathematical model of FPA unit was constructed based on matrix transformation theory. According to characteristics of FPA, Image enhancement algorithm which combined with mathematical morphology and edge detection are established. First of all, Image profile is obtained by using the edge detection combine with mathematical morphological operators. And then, through filling the template profile by original image to get the ideal background image, The image noise can be removed on the base of the above method. The experiments show that utilizing the proposed algorithm can enhance image detail and the signal to noise ratio.

  18. Color filters including infrared cut-off integrated on CMOS image sensor.

    PubMed

    Frey, Laurent; Parrein, Pascale; Raby, Jacques; Pellé, Catherine; Hérault, Didier; Marty, Michel; Michailos, Jean

    2011-07-04

    A color image was taken with a CMOS image sensor without any infrared cut-off filter, using red, green and blue metal/dielectric filters arranged in Bayer pattern with 1.75 µm pixel pitch. The three colors were obtained by a thickness variation of only two layers in the 7-layer stack, with a technological process including four photolithography levels. The thickness of the filter stack was only half of the traditional color resists, potentially enabling a reduction of optical crosstalk for smaller pixels. Both color errors and signal to noise ratio derived from optimized spectral responses are expected to be similar to color resists associated with infrared filter.

  19. Lamb-Wave-Based Tomographic Imaging Techniques for Hole-Edge Corrosion Monitoring in Plate Structures

    PubMed Central

    Wang, Dengjiang; Zhang, Weifang; Wang, Xiangyu; Sun, Bo

    2016-01-01

    This study presents a novel monitoring method for hole-edge corrosion damage in plate structures based on Lamb wave tomographic imaging techniques. An experimental procedure with a cross-hole layout using 16 piezoelectric transducers (PZTs) was designed. The A0 mode of the Lamb wave was selected, which is sensitive to thickness-loss damage. The iterative algebraic reconstruction technique (ART) method was used to locate and quantify the corrosion damage at the edge of the hole. Hydrofluoric acid with a concentration of 20% was used to corrode the specimen artificially. To estimate the effectiveness of the proposed method, the real corrosion damage was compared with the predicted corrosion damage based on the tomographic method. The results show that the Lamb-wave-based tomographic method can be used to monitor the hole-edge corrosion damage accurately. PMID:28774041

  20. MR histological correlation: a method for cutting specimens along the imaging plane in animal or ex vivo experiments.

    PubMed

    Rouvière, Olivier; Reynolds, Carol; Hulshizer, Thomas; Rossman, Phillip; Le, Yuan; Felmlee, Joel P; Ehman, Richard L

    2006-01-01

    To assess a method aimed at cutting histological specimens along the magnetic resonance (MR) imaging plane. The method is performed in two steps: the imaging plane (defined by three acrylic paint markers) is made horizontal under MR guidance by using a mobile platform that can be rotated in three directions (PlaneFinder device [PFD]); then, the specimen is embedded in wax and cut horizontally. Three-dimensional images parallel to the markers' plane were obtained on 31 pork muscles containing a central hole with a pyramidal shape, with a technique of reference (RT images) and with PFD (PF images), before and after fixation. The last 17 fixed specimens were cut in the markers' plane (tissue section [TS] images). The central hole area (CHA) in the markers' plane was used to compare RT, PF, and TS images. Using a workstation, PF images were rotated and translated to estimate the shift along each direction that could explain the entire CHA difference between RT, PF, and TS images (maximum error, worst-case scenario). Excellent correlation was found between RT and PF images (r = 0.989, slope = 1.0175), PF and TS images (r = 0.991, slope = 1.0058), and RT images on fresh specimens and TS images (r = 0.979, slope = 1.0732). For each step, the maximum angle error was < or = 3 degrees in 88-95% of the specimens. Our methodology can be used to cut specimens along the imaging plane with high accuracy.

  1. The implementation of a thermal imaging camera for testing the temperature of the cutting zone in turning

    NASA Astrophysics Data System (ADS)

    Ślusarczyk, Ł.

    2016-09-01

    The paper presents research concerning temperature distribution in cutting zone in AMS 5643 steel turning with the help of a thermal imaging camera. Experimental studies served for the verification of the material model, used in simulation examinations for the optimization of cutting data.

  2. Denoising Diffusion-Weighted Magnitude MR Images using Rank and Edge Constraints

    PubMed Central

    Lam, Fan; Babacan, S. Derin; Haldar, Justin P.; Weiner, Michael W.; Schuff, Norbert; Liang, Zhi-Pei

    2013-01-01

    Purpose To improve signal-to-noise ratio (SNR) for diffusion-weighted MR images. Methods A new method is proposed for denoising diffusion-weighted magnitude images. The proposed method formulates the denoising problem as an maximum a posteriori estimation problem based on Rician/noncentral χ likelihood models, incorporating an edge prior and a low-rank model. The resulting optimization problem is solved efficiently using a half-quadratic method with an alternating minimization scheme. Results The performance of the proposed method has been validated using simulated and experimental data. Diffusion-weighted images and noisy data were simulated based on the diffusion tensor imaging (DTI) model and Rician/noncentral χ distributions. The simulation study (with known gold standard) shows substantial improvements in SNR and diffusion tensor es-timation after denoising. In-vivo diffusion imaging data at different b-values were acquired. Based on the experimental data, qualitative improvement in image quality and quantitative im-provement in diffusion tensor estimation were demonstrated. Additionally, the proposed method is shown to outperform one of the state-of-the-art non-local means based denoising algorithms, both qualitatively and quantitatively. Conclusion The SNR of diffusion-weighted images can be effectively improved with rank and edge constraints, resulting in an improvement in diffusion parameter estimation accuracy. PMID:23568755

  3. Second Generation Gold Nanobeacons for Robust K-Edge Imaging with Multi-Energy CT

    PubMed Central

    Schirra, Carsten O.; Senpan, Angana; Roessl, Ewald; Thran, Axel; Stacy, Allen J.; Wu, Lina; Proska, Roland; Pan, Dipanjan

    2012-01-01

    Spectral CT is the newest advancement in CT imaging technology, which enhances traditional CT images with the capability to image and quantify certain elements based on their distinctive K-edge energies. K-edge imaging feature recognizes high accumulations of targeted elements and presents them as colorized voxels against the normal grayscale X-ray background offering promise to overcome the relatively low inherent contrast within soft tissue and distinguish the high attenuation of calcium from contrast enhanced targets. Towards this aim, second generation gold nanobeacons (GNB2), which incorporate at least five times more metal than the previous generation was developed. The particles were synthesized as lipid-encapsulated, vascularly constrained (>120 nm) nanoparticle incorporating tiny gold nanoparticles (2–4 nm) within a polysorbate core. The choice of core material dictated to achieve a higher metal loading. The particles were thoroughly characterized by physicochemical techniques. This study reports one of the earlier examples of spectral CT imaging with gold nanoparticles demonstrating the potential for targeted in vitro and in vivo imaging and eliminates calcium interference with CT. The use of statistical image reconstruction shows high SNR may allow dose reduction and/or faster scan times. PMID:23185109

  4. Cumulative sums for edge determination of a single object in PET and SPECT images

    NASA Astrophysics Data System (ADS)

    Protonotarios, Nicholas E.; Spyrou, George M.; Kastis, George A.

    2016-08-01

    The issue of edge determination of a single object in reconstructed nuclear medicine images has been examined thoroughly in the past, nevertheless most of the investigation has focused on the concepts of either numerical sinogram differentiation or segmentation. This work aims to develop an automated method for determining the contour of a single convex object in PET and SPECT reconstructed images, which can be used for computing body edges for attenuation correction, as well as for eliminating streak artifacts outside the specific object. This was accomplished by implementing a modified cumulative sums (CUSUM) scheme in the sinogram. Our method can automatically detect the object's boundary in the reconstructed image. This approach has been tested in simulated as well as real phantoms and it performed efficiently for all convex objects. We were able to detect the contour of a single object in the image space, which in turn enabled us to eliminate streak artifacts outside and thus to obtain body edges necessary for attenuation correction.

  5. At the coalface and the cutting edge: general practitioners’ accounts of the rewards of engaging with HIV medicine

    PubMed Central

    2013-01-01

    Background HIV has become a chronic manageable infection in the developed world, and early and lifelong treatment has the potential to significantly reduce transmission rates in the community. A skilled and motivated HIV medical workforce will be required to achieve these health management and prevention outcomes, but concerns have been noted in a number of settings about the challenges of recruiting a new generation of clinicians to HIV medicine. Methods As part of a larger qualitative study of the HIV general practice workforce in Australia, in-depth interviews were conducted with 31 general practitioners accredited to prescribe HIV medications in community settings. A thematic analysis was conducted of the de-identified transcripts, and this paper describes and interprets accounts of the rewards of pursuing and sustaining an engagement with HIV medicine in general practice settings. Results The rewards of initially becoming involved in providing care to people living with HIV were described as interest and inspiration, community calling and right place, right time. The rewards which then supported and sustained that engagement over time were described as challenge and change, making a difference and enhanced professional identity. Participants viewed the role of primary care doctor with special expertise in HIV as occupying an ideal interface between the ‘coalface’ and the ‘cutting edge’, and offering a unique opportunity for general practitioners to feel intimately connected to both community needs and scientific change. Conclusions Approaches to recruiting and retaining the HIV medical workforce should build upon the intellectual and social rewards of this work, as well as the sense of professional belonging and connection which is imbued between both doctors and patients and across the global and national networks of HIV clinicians. Insights regarding the rewards of engaging with HIV medicine may also be useful in enhancing the prospect of general

  6. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup

    PubMed Central

    Diemoz, Paul C.; Vittoria, Fabio A.; Hagen, Charlotte K.; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H.; Rau, Christoph; Robinson, Ian K.; Bravin, Alberto; Olivo, Alessandro

    2015-01-01

    A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects. PMID:26134813

  7. Deformable registration using edge-preserving scale space for adaptive image-guided radiation therapy.

    PubMed

    Li, Dengwang; Wang, Hongjun; Yin, Yong; Wang, Xiuying

    2011-11-15

    Incorporating of daily cone-beam computer tomography (CBCT) image into online radiation therapy process can achieve adaptive image-guided radiation therapy (AIGRT). Registration of planning CT (PCT) and daily CBCT are the key issues in this process. In our work, a new multiscale deformable registration method is proposed by combining edge-preserving scale space with the multilevel free-form deformation (FFD) grids for CBCT-based AIGRT system. The edge-preserving scale space, which is able to select edges and contours of images according to their geometric size, is derived from the total variation model with the L1 norm (TV-L1). At each scale, despite the noise and contrast resolution differences between the PCT and CBCT, the selected edges and contours are sufficiently strong to drive the deformation using the FFD grid, and the edge-preserving property ensures more meaningful spatial information for mutual information (MI)-based registration. At last, the deformation fields are gained by a coarse to fine manner. Furthermore, in consideration of clinical application we designed an optimal estimation of the TV-L1 parameters by minimizing the defined offset function for automated registration. Six types of patients are studied in our work, including rectum, prostate, lung, H&N (head and neck), breast, and chest cancer patients. The experiment results demonstrate the significance of the proposed method both quantitatively with ground truth known and qualitatively with ground truth unknown. The applications for AIGRT, including adaptive deformable recontouring and redosing, and DVH (dose volume histogram) analysis in the course of radiation therapy are also studied.

  8. Automatic graph-cut based segmentation of bones from knee magnetic resonance images for osteoarthritis research

    PubMed Central

    Prescott, Jeff W.; Gurcan, Metin N.

    2011-01-01

    In this paper, a new, fully automated, content-based system is proposed for knee bone segmentation from magnetic resonance images (MRI). The purpose of the bone segmentation is to support the discovery and characterization of imaging biomarkers for the incidence and progression of osteoarthritis, a debilitating joint disease, which affects a large portion of the aging population. The segmentation algorithm includes a novel content-based, two-pass disjoint block discovery mechanism, which is designed to support automation, segmentation initialization, and post processing. The block discovery is achieved by classifying the image content to bone and background blocks according to their similarity to the categories in the training data collected from typical bone structures. The classified blocks are then used to design an efficient graph-cut based segmentation algorithm. This algorithm requires constructing a graph using image pixel data followed by applying a maximum-flow algorithm which generates a minimum graph-cut that corresponds to an initial image segmentation. Content-based refinements and morphological operations are then applied to obtain the final segmentation. The proposed segmentation technique does not require any user interaction and can distinguish between bone and highly similar adjacent structures, such as fat tissues with high accuracy. The performance of the proposed system is evaluated by testing it on 376 MR images from the Osteoarthritis Initiative (OAI) database. This database included a selection of single images containing the femur and tibia from 200 subjects with varying levels of osteoarthritis severity. Additionally, a full three-dimensional segmentation of the bones from ten subjects with 14 slices each, and synthetic images with background having intensity and spatial characteristics similar to those of bone are used to assess the robustness and consistency of the developed algorithm. The results show an automatic bone detection rate of

  9. Quality optimized medical image information hiding algorithm that employs edge detection and data coding.

    PubMed

    Al-Dmour, Hayat; Al-Ani, Ahmed

    2016-04-01

    The present work has the goal of developing a secure medical imaging information system based on a combined steganography and cryptography technique. It attempts to securely embed patient's confidential information into his/her medical images. The proposed information security scheme conceals coded Electronic Patient Records (EPRs) into medical images in order to protect the EPRs' confidentiality without affecting the image quality and particularly the Region of Interest (ROI), which is essential for diagnosis. The secret EPR data is converted into ciphertext using private symmetric encryption method. Since the Human Visual System (HVS) is less sensitive to alterations in sharp regions compared to uniform regions, a simple edge detection method has been introduced to identify and embed in edge pixels, which will lead to an improved stego image quality. In order to increase the embedding capacity, the algorithm embeds variable number of bits (up to 3) in edge pixels based on the strength of edges. Moreover, to increase the efficiency, two message coding mechanisms have been utilized to enhance the ±1 steganography. The first one, which is based on Hamming code, is simple and fast, while the other which is known as the Syndrome Trellis Code (STC), is more sophisticated as it attempts to find a stego image that is close to the cover image through minimizing the embedding impact. The proposed steganography algorithm embeds the secret data bits into the Region of Non Interest (RONI), where due to its importance; the ROI is preserved from modifications. The experimental results demonstrate that the proposed method can embed large amount of secret data without leaving a noticeable distortion in the output image. The effectiveness of the proposed algorithm is also proven using one of the efficient steganalysis techniques. The proposed medical imaging information system proved to be capable of concealing EPR data and producing imperceptible stego images with minimal

  10. Detection of decay in fresh-cut lettuce using hyperspectral imaging and chlorophyll fluorescence imaging

    USDA-ARS?s Scientific Manuscript database

    Fresh-cut lettuce sold in modified atmosphere packaging (MAP) is a desirable, but highly perishable product. Decay of tissue can start a few days after processing and may be difficult to detect by quick visual observation. A system for early detection of decay and gradual evaluation of its progress ...

  11. An energy dispersive bent Laue monochromator for K-edge subtraction imaging

    SciTech Connect

    Samadi, Nazanin; Martinson, Mercedes; Bassey, Bassey; Gomez, Ariel; Belev, George; Chapman, Dean

    2016-07-27

    K-Edge Subtraction (KES) is a powerful synchrotron imaging method that allows the quantifiable determination of a contrast element (e.g. iodine) and matrix material (usually represented as water) in both projection imaging and computed tomography. A bent Laue monochromator has been developed that has very good focal and energy dispersive properties for KES. Approximately 5% of the vertical beam profile is involved in “edge crossing” energies, thus no splitter is employed as has been done with previous implementations where approximately 33% of the beam size was blocked. The beam can be narrowed vertically allowing a smaller crossover angle than a splitter based system which minimizes artifacts. The combination of good spatial resolution, energy dispersive properties, flux and a unique approach to data analysis make this system nearly ideal for KES.

  12. An improved teaching-learning based robust edge detection algorithm for noisy images.

    PubMed

    Thirumavalavan, Sasirooba; Jayaraman, Sasikala

    2016-11-01

    This paper presents an improved Teaching Learning Based Optimization (TLO) and a methodology for obtaining the edge maps of the noisy real life digital images. TLO is a population based algorithm that simulates the teaching-learning mechanism in class rooms, comprising two phases of teaching and learning. The 'Teaching Phase' represents learning from the teacher and 'Learning Phase' indicates learning by the interaction between learners. This paper introduces a third phase denoted by "Avoiding Phase" that helps to keep the learners away from the worst students with a view of exploring the problem space more effectively and escaping from the sub-optimal solutions. The improved TLO (ITLO) explores the solution space and provides the global best solution. The edge detection problem is formulated as an optimization problem and solved using the ITLO. The results of real life and medical images illustrate the performance of the developed method.

  13. A model of natural image edge co-occurrence in the rototranslation group.

    PubMed

    Sanguinetti, Gonzalo; Citti, Giovanna; Sarti, Alessandro

    2010-12-31

    In this paper, we propose to model the edge information contained in natural scenes as points in the 3D space of positions and orientations. This space is equipped with a strong geometrical structure and it is identified as the rototranslation group. In this space, we compute a histogram of co-occurrence of edges from a database of natural images and show that it can be interpreted as a probability density function, expressed by the fundamental solution of a suitable Fokker-Planck equation defined in the 3D structured space. Both estimated statistics and model predictions are reconsidered and compared with the partial gestalt association fields proposed by D. J. Field, A. Hayes, and R. F. Hess (1993). Finally, parametric identification allows to estimate the variance of the co-occurrence random process in natural images.

  14. 3D Materials image segmentation by 2D propagation: a graph-cut approach considering homomorphism.

    PubMed

    Waggoner, Jarrell; Zhou, Youjie; Simmons, Jeff; De Graef, Marc; Wang, Song

    2013-12-01

    Segmentation propagation, similar to tracking, is the problem of transferring a segmentation of an image to a neighboring image in a sequence. This problem is of particular importance to materials science, where the accurate segmentation of a series of 2D serial-sectioned images of multiple, contiguous 3D structures has important applications. Such structures may have distinct shape, appearance, and topology, which can be considered to improve segmentation accuracy. For example, some materials images may have structures with a specific shape or appearance in each serial section slice, which only changes minimally from slice to slice, and some materials may exhibit specific inter-structure topology that constrains their neighboring relations. Some of these properties have been individually incorporated to segment specific materials images in prior work. In this paper, we develop a propagation framework for materials image segmentation where each propagation is formulated as an optimal labeling problem that can be efficiently solved using the graph-cut algorithm. Our framework makes three key contributions: 1) a homomorphic propagation approach, which considers the consistency of region adjacency in the propagation; 2) incorporation of shape and appearance consistency in the propagation; and 3) a local non-homomorphism strategy to handle newly appearing and disappearing substructures during this propagation. To show the effectiveness of our framework, we conduct experiments on various 3D materials images, and compare the performance against several existing image segmentation methods.

  15. Investigation of X-ray fluorescence computed tomography (XFCT) and K-edge imaging.

    PubMed

    Bazalova, Magdalena; Kuang, Yu; Pratx, Guillem; Xing, Lei

    2012-08-01

    This work provides a comprehensive Monte Carlo study of X-ray fluorescence computed tomography (XFCT) and K-edge imaging system, including the system design, the influence of various imaging components, the sensitivity and resolution under various conditions. We modified the widely used EGSnrc/DOSXYZnrc code to simulate XFCT images of two acrylic phantoms loaded with various concentrations of gold nanoparticles and Cisplatin for a number of XFCT geometries. In particular, reconstructed signal as a function of the width of the detector ring, its angular coverage and energy resolution were studied. We found that XFCT imaging sensitivity of the modeled systems consisting of a conventional X-ray tube and a full 2-cm-wide energy-resolving detector ring was 0.061% and 0.042% for gold nanoparticles and Cisplatin, respectively, for a dose of ∼ 10 cGy. Contrast-to-noise ratio (CNR) of XFCT images of the simulated acrylic phantoms was higher than that of transmission K-edge images for contrast concentrations below 0.4%.

  16. Field flatteners fabricated with a rapid prototyper for K-edge subtraction imaging of small animals

    NASA Astrophysics Data System (ADS)

    Zhu, Ying; Zhang, Honglin; Bewer, Brian; Florin Gh. Popescu, Bogdan; Nichol, Helen; Chapman, Dean

    2008-04-01

    One of the difficulties in X-ray imaging is the need to record a wide dynamic range of intensities on the detector. For example, some rays may miss the object being imaged entirely while others may suffer many orders of magnitude attenuation in passing through. In K-edge subtraction (KES) [E. Rubenstein, et al., Trans. Am. Clin. Climatol. Assoc. 97 (1985) 27.] imaging subtle differences in transmission through an object about the absorption edge of an element are used to create an image of the projected density of that element. This is done by a logarithmic subtraction of images acquired with energies above and below the absorption edge. For KES, the detector must register this transmitted intensity range in a linear manner for the subtraction method to be successful. The range of intensities which may strike the detector has inspired the concept of a field flattener. A field flattener is a device placed in the beam path that attenuates the input monochromatic beam to equalize X-ray absorption due to differences in the density of soft and hard tissues of an object before it passes through the object and thus achieves a flattened image. This removes the need for a wide dynamic range linear detector and allows detectors with modest performance to be used successfully in KES applications. The field flattener improves the S/ N ratio since X-ray exposures can be increased up to detector saturation. However, a field flattener removes anatomical information from each raw image (above or below K-edge) that may provide useful landmarks. Using rapid prototyping technology, two sets of field flatteners were fabricated and used in a KES experiment. This paper describes the procedure to design and fabricate field flatteners based on animal images from X-ray computed tomography (CT). Analysis of experimental data and KES images of a rat head with and without the field flattener are also presented. The results show a promising improvement of S/ N ratio using a field flattener

  17. Turbulent Jet-Edge and Cavity Flows: Assessment Via Cinema Particle Image Velocimetry

    NASA Astrophysics Data System (ADS)

    Lin, Jung-Chang; Rockwell, Donald

    1998-11-01

    Although quasi-laminar jet-edge and cavity oscillations have been addressed extensively in recent decades, the issue arises as to whether self-sustained, quasi-coherent oscillations are attainable in presence of a fully-developed turbulent inflow. The nature of such oscillations is characterized using an integrated cinema particle image velocimetry-pressure measurement system. This approach employs a high framing rate camera in conjunction with a scanning-laser version of high-image-density particle image velocimetry, with the goal of generating space-time representations of the flow. Simultaneously, instantaneous pressures along the impingement surface of the wedge/edge are acquired. This approach allows the instantaneous velocity and vorticity fields to be interpreted in relation to the instantaneous surface loading. Highly coherent oscillations of the jet-edge system are attainable; on the other hand, the cavity configuration exhibits a degree of coherence with pronounced amplitude and frequency modulations. http://www.lehigh.edu/dept/mecheng/inmem/research/rfluids/index.html

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

    NASA Astrophysics Data System (ADS)

    Tse, Peter W.; Wang, Gaochao

    2017-05-01

    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.

  19. Graph cut and image intensity-based splitting improves nuclei segmentation in high-content screening

    NASA Astrophysics Data System (ADS)

    Farhan, Muhammad; Ruusuvuori, Pekka; Emmenlauer, Mario; Rämö, Pauli; Yli-Harja, Olli; Dehio, Christoph

    2013-02-01

    Quantification of phenotypes in high-content screening experiments depends on the accuracy of single cell analysis. In such analysis workflows, cell nuclei segmentation is typically the first step and is followed by cell body segmentation, feature extraction, and subsequent data analysis workflows. Therefore, it is of utmost importance that the first steps of high-content analysis are done accurately in order to guarantee correctness of the final analysis results. In this paper, we present a novel cell nuclei image segmentation framework which exploits robustness of graph cut to obtain initial segmentation for image intensity-based clump splitting method to deliver the accurate overall segmentation. By using quantitative benchmarks and qualitative comparison with real images from high-content screening experiments with complicated multinucleate cells, we show that our method outperforms other state-of-the-art nuclei segmentation methods. Moreover, we provide a modular and easy-to-use implementation of the method for a widely used platform.

  20. Real-time planar segmentation of depth images: from three-dimensional edges to segmented planes

    NASA Astrophysics Data System (ADS)

    Javan Hemmat, Hani; Bondarev, Egor; de With, Peter H. N.

    2015-09-01

    Real-time execution of processing algorithms for handling depth images in a three-dimensional (3-D) data framework is a major challenge. More specifically, considering depth images as point clouds and performing planar segmentation requires heavy computation, because available planar segmentation algorithms are mostly based on surface normals and/or curvatures, and, consequently, do not provide real-time performance. Aiming at the reconstruction of indoor environments, the spaces mainly consist of planar surfaces, so that a possible 3-D application would strongly benefit from a real-time algorithm. We introduce a real-time planar segmentation method for depth images avoiding any surface normal calculation. First, we detect 3-D edges in a depth image and generate line segments between the identified edges. Second, we fuse all the points on each pair of intersecting line segments into a plane candidate. Third and finally, we implement a validation phase to select planes from the candidates. Furthermore, various enhancements are applied to improve the segmentation quality. The GPU implementation of the proposed algorithm segments depth images into planes at the rate of 58 fps. Our pipeline-interleaving technique increases this rate up to 100 fps. With this throughput rate improvement, the application benefit of our algorithm may be further exploited in terms of quality and enhancing the localization.

  1. A matching algorithm based on multiresolution and edge enhancement using the optimum size of image

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Zhang, Guangjun

    2006-11-01

    This paper analyzes the relation between the size of real time image and the matching time, and a optimum size of image is improved while maintaining a high probability of correct matching. An accelerated normalized product correlation similarity measure is proposed for practical application. In order to enhance the edge feature of image and increase the probability of correct matching, this algorithm enhances the edge of image using the sobel operator. To use image matching in cruise missile, an approach which can accelerate the normalized product correlation matching algorithm is designed and implemented by adopting "from coarse to precise" control strategy. When in the coarse phase, 5 matchingpoint are choosed, which can contain the primary point by the simulation experimental results. When in the precise phase, a proper switching-level Q is proposed, and the searching is performed around each matching-point. If correlation coefficient is above Q, the searching process ends. The simulation experimental results demonstrate the efficiency and practicability of the matching control strategy and the excellent adaptability of the proposed algorithm to grayscale distortion, noise disturbance, geometric rotation. The improved algorithm maintains a high probability of correct matching, and the running time reduces 1/5 to 1/8, or even more.

  2. High dynamic range infrared images detail enhancement based on local edge preserving filter

    NASA Astrophysics Data System (ADS)

    Song, Qiong; Wang, Yuehuan; Bai, Kun

    2016-07-01

    In the field of infrared (IR) image processing, displaying a high dynamic range (HDR) image on a low dynamic range display equipment with a natural visual effect, clear details on local areas and less artifacts is an important issue. In this paper, we present a new approach to display HDR IR images with contrast enhancement. First, the local edge-preserving filter (LEPF) is utilized to separate the image into a base layer and detail layer(s). After the filtering procedure, we use an adaptive Gamma transformation to adjust the gray distribution of the base layer, and stretch the detail layer based on a human visual effect principle. Then, we recombine the detail layer and base layer to obtain the enhance output. Finally, we adjust the luminance of output by applying multiple exposure fusion method. The experimental results demonstrate that our proposed method can provide a significant performance in terms of enhancing details and less artifacts than the state of the arts.

  3. WE-D-9A-04: Improving Multi-Modality Image Registration Using Edge-Based Transformations

    SciTech Connect

    Wang, Y; Tyagi, N; Veeraraghavan, H; Deasy, J

    2014-06-15

    Purpose: Multi-modality deformable image registration (DIR) for head and neck (HN) radiotherapy is difficult, particularly when matching computed tomography (CT) scans with magnetic resonance imaging (MRI) scans. We hypothesized that the ‘shared information’ between images of different modalities was to be found in some form of edge-based transformation, and that novel edge-based DIR methods might outperform standard DIR methods. Methods: We propose a novel method that combines gray-scale edge-based morphology and mutual information (MI) in two stages. In the first step, we applied a modification of a previously published mathematical morphology method as an efficient gray scale edge estimator, with denoising function. The results were fed into a MI-based solver (plastimatch). The method was tested on 5 HN patients with pretreatment CT and MR datasets and associated follow-up weekly MR scans. The followup MRs showed significant regression in tumor and normal structure volumes as compared to the pretreatment MRs. The MR images used in this study were obtained using fast spin echo based T2w images with a 1 mm isotropic resolution and FOV matching the CT scan. Results: In all cases, the novel edge-based registration method provided better registration quality than MI-based DIR using the original CT and MRI images. For example, the mismatch in carotid arteries was reduced from 3–5 mm to within 2 mm. The novel edge-based method with different registration regulation parameters did not show any distorted deformations as compared to the non-realistic deformations resulting from MI on the original images. Processing time was 1.3 to 2 times shorter (edge vs. non-edge). In general, we observed quality improvement and significant calculation time reduction with the new method. Conclusion: Transforming images to an ‘edge-space,’ if designed appropriately, greatly increases the speed and accuracy of DIR.

  4. Semi-supervised segmentation of ultrasound images based on patch representation and continuous min cut.

    PubMed

    Ciurte, Anca; Bresson, Xavier; Cuisenaire, Olivier; Houhou, Nawal; Nedevschi, Sergiu; Thiran, Jean-Philippe; Cuadra, Meritxell Bach

    2014-01-01

    Ultrasound segmentation is a challenging problem due to the inherent speckle and some artifacts like shadows, attenuation and signal dropout. Existing methods need to include strong priors like shape priors or analytical intensity models to succeed in the segmentation. However, such priors tend to limit these methods to a specific target or imaging settings, and they are not always applicable to pathological cases. This work introduces a semi-supervised segmentation framework for ultrasound imaging that alleviates the limitation of fully automatic segmentation, that is, it is applicable to any kind of target and imaging settings. Our methodology uses a graph of image patches to represent the ultrasound image and user-assisted initialization with labels, which acts as soft priors. The segmentation problem is formulated as a continuous minimum cut problem and solved with an efficient optimization algorithm. We validate our segmentation framework on clinical ultrasound imaging (prostate, fetus, and tumors of the liver and eye). We obtain high similarity agreement with the ground truth provided by medical expert delineations in all applications (94% DICE values in average) and the proposed algorithm performs favorably with the literature.

  5. Semi-Supervised Segmentation of Ultrasound Images Based on Patch Representation and Continuous Min Cut

    PubMed Central

    Ciurte, Anca; Bresson, Xavier; Cuisenaire, Olivier; Houhou, Nawal; Nedevschi, Sergiu; Thiran, Jean-Philippe; Cuadra, Meritxell Bach

    2014-01-01

    Ultrasound segmentation is a challenging problem due to the inherent speckle and some artifacts like shadows, attenuation and signal dropout. Existing methods need to include strong priors like shape priors or analytical intensity models to succeed in the segmentation. However, such priors tend to limit these methods to a specific target or imaging settings, and they are not always applicable to pathological cases. This work introduces a semi-supervised segmentation framework for ultrasound imaging that alleviates the limitation of fully automatic segmentation, that is, it is applicable to any kind of target and imaging settings. Our methodology uses a graph of image patches to represent the ultrasound image and user-assisted initialization with labels, which acts as soft priors. The segmentation problem is formulated as a continuous minimum cut problem and solved with an efficient optimization algorithm. We validate our segmentation framework on clinical ultrasound imaging (prostate, fetus, and tumors of the liver and eye). We obtain high similarity agreement with the ground truth provided by medical expert delineations in all applications (94% DICE values in average) and the proposed algorithm performs favorably with the literature. PMID:25010530

  6. A Fast Algorithm for Denoising Magnitude Diffusion-Weighted Images with Rank and Edge Constraints

    PubMed Central

    Lam, Fan; Liu, Ding; Song, Zhuang; Schuff, Norbert; Liang, Zhi-Pei

    2015-01-01

    Purpose To accelerate denoising of magnitude diffusion-weighted images subject to joint rank and edge constraints. Methods We extend a previously proposed majorize-minimize (MM) method for statistical estimation that involves noncentral χ distributions and joint rank and edge constraints. A new algorithm is derived which decomposes the constrained noncentral χ denoising problem into a series of constrained Gaussian denoising problems each of which is then solved using an efficient alternating minimization scheme. Results The performance of the proposed algorithm has been evaluated using both simulated and experimental data. Results from simulations based on ex vivo data show that the new algorithm achieves about a factor of 10 speed up over the original Quasi-Newton based algorithm. This improvement in computational efficiency enabled denoising of large data sets containing many diffusion-encoding directions. The denoising performance of the new efficient algorithm is found to be comparable to or even better than that of the original slow algorithm. For an in vivo high-resolution Q-ball acquisition, comparison of fiber tracking results around hippocampus region before and after denoising will also be shown to demonstrate the denoising effects of the new algorithm. Conclusion The optimization problem associated with denoising noncentral χ distributed diffusion-weighted images subject to joint rank and edge constraints can be solved efficiently using an MM-based algorithm. PMID:25733066

  7. A fast algorithm for denoising magnitude diffusion-weighted images with rank and edge constraints.

    PubMed

    Lam, Fan; Liu, Ding; Song, Zhuang; Schuff, Norbert; Liang, Zhi-Pei

    2016-01-01

    To accelerate denoising of magnitude diffusion-weighted images subject to joint rank and edge constraints. We extend a previously proposed majorize-minimize method for statistical estimation that involves noncentral χ distributions to incorporate joint rank and edge constraints. A new algorithm is derived which decomposes the constrained noncentral χ denoising problem into a series of constrained Gaussian denoising problems each of which is then solved using an efficient alternating minimization scheme. The performance of the proposed algorithm has been evaluated using both simulated and experimental data. Results from simulations based on ex vivo data show that the new algorithm achieves about a factor of 10 speed up over the original Quasi-Newton-based algorithm. This improvement in computational efficiency enabled denoising of large datasets containing many diffusion-encoding directions. The denoising performance of the new efficient algorithm is found to be comparable to or even better than that of the original slow algorithm. For an in vivo high-resolution Q-ball acquisition, comparison of fiber tracking results around hippocampus region before and after denoising will also be shown to demonstrate the denoising effects of the new algorithm. The optimization problem associated with denoising noncentral χ distributed diffusion-weighted images subject to joint rank and edge constraints can be solved efficiently using a majorize-minimize-based algorithm. © 2015 Wiley Periodicals, Inc.

  8. Cutting stems before relaxing xylem tension induces artefacts in Vitis coignetiae, as evidenced by magnetic resonance imaging.

    PubMed

    Ogasa, Mayumi Y; Utsumi, Yasuhiro; Miki, Naoko H; Yazaki, Kenichi; Fukuda, Kenji

    2016-02-01

    It was recently reported that cutting artefacts occur in some species when branches under tension are cut, even under water. We used non-destructive magnetic resonance imaging (MRI) to investigate the change in xylem water distribution at the cellular level in Vitis coignetiae standing stems before and after relaxing tension. Less than 3% of vessels were cavitated when stems under tension were cut under water at a position shorter than the maximum vessel length (MVL) from the MRI point, in three of four plants. The vessel contents remained at their original status, and cutting artefact vessel cavitation declined to <1% when stems were cut at a position farther than the MVL from the MRI point. Water infiltration into the originally cavitated vessels after cutting the stem, i.e. vessel refilling, was found in <1% of vessels independent of cutting position on three of nine plants. The results indicate that both vessel cavitation and refilling occur in xylem tissue under tension following stem cutting, but its frequency is quite small, and artefacts can be minimized altogether if the distance between the monitoring position and the cutting point is longer than the MVL.

  9. The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry.

    PubMed

    Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

    2016-01-01

    Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling.

  10. The risk for immediate postoperative complications after pancreaticoduodenectomy is increased by high frequency of acinar cells and decreased by prevalent fibrosis of the cut edge of pancreas.

    PubMed

    Laaninen, Matias; Bläuer, Merja; Vasama, Kaija; Jin, Haitao; Räty, Sari; Sand, Juhani; Nordback, Isto; Laukkarinen, Johanna

    2012-08-01

    Soft pancreas is considered as a factor for pancreatitis after pancreaticoduodenectomy, which in turn constitutes a high risk for local complications. The aim was to analyze the proportion of different cell types in the cut edge of pancreas (CEP) in relation to postoperative pancreatitis and other complications after pancreaticoduodenectomy. Data from postoperative follow-up was collected on 40 patients who had undergone pancreaticoduodenectomy. Positive urine trypsinogen-2, an early detector of pancreatitis, was checked on days 1 to 6 after operation. Drain amylase was measured on postoperative day 3. Anastomotic leakages, delayed gastric emptying, and other complications were registered. The areas of different cell types were calculated from the entire hematoxylin-eosin-stained section of CEP. High frequency of acinar cells in the CEP significantly increased positive urine trypsinogen-2 days, drain amylase values, and delayed gastric emptying. In a subgroup of patients with more than 40% acini in the CEP, there were significantly more postoperative complications. Increased fibrosis correlated with a small number of positive urine trypsinogen-2 days and postoperative complications. A large number of acinar cells in the CEP increases, whereas extensive fibrosis in the CEP decreases, the risk for postoperative complications after pancreaticoduodenectomy. These results emphasize the importance of acini in the development of postoperative complications.

  11. The Role of Dafachronic Acid Signaling in Development and Longevity in Caenorhabditis elegans: Digging Deeper Using Cutting-Edge Analytical Chemistry

    PubMed Central

    Aguilaniu, Hugo; Fabrizio, Paola; Witting, Michael

    2016-01-01

    Steroid hormones regulate physiological processes in species ranging from plants to humans. A wide range of steroid hormones exist, and their contributions to processes, such as growth, reproduction, development, and aging, is almost always complex. Understanding the biosynthetic pathways that generate steroid hormones and the signaling pathways that mediate their effects is thus of fundamental importance. In this work, we review recent advances in (i) the biological role of steroid hormones in the roundworm Caenorhabditis elegans and (ii) the development of novel methods to facilitate the detection and identification of these molecules. Our current understanding of steroid signaling in this simple organism serves to illustrate the challenges we face moving forward. First, it seems clear that we have not yet identified all of the enzymes responsible for steroid biosynthesis and/or degradation. Second, perturbation of steroid signaling affects a wide range of phenotypes, and subtly different steroid molecules can have distinct effects. Finally, steroid hormone levels are critically important, and minute variations in quantity can profoundly impact a phenotype. Thus, it is imperative that we develop innovative analytical tools and combine them with cutting-edge approaches including comprehensive and highly selective liquid chromatography coupled to mass spectrometry based on new methods such as supercritical fluid chromatography coupled to mass spectrometry (SFC-MS) if we are to obtain a better understanding of the biological functions of steroid signaling. PMID:26903948

  12. Characterizing the dependence of thick-mask edge effects on illumination angle using AIMS images

    NASA Astrophysics Data System (ADS)

    Shanker, Aamod; Sczyrba, Martin; Lange, Falk; Connolly, Brid; Neureuther, Andy; Waller, Laura

    2015-03-01

    Mask topography contributes diffraction-induced phase near edges, affecting the through-focus intensity variation and hence the process window at the wafer. We analyze the impact of edge diffraction on projection printing directly with experiments on an aerial image measurement system (AIMS). We show here that topographic effects change with illumination angle and can be quantified using through-focus intensity measurements. Off- axis incidence influences not just defocus image behavior (as for normal incidence), but also the at-focus intensity at wafer. Moreover, with oblique illumination, mask diffraction varies for left-facing and right-facing sidewalls, the nature of the asymmetry being polarization dependent. The image degradation due the polarization parallel to the sidewall (TE) is seen to be stronger, owing to the interplay of mask topography and pupil filtering in the imaging system. This translates to a CD variation of 2% between the two polarizations, even at focus. A simple thin-mask boundary layer model that treats each sidewall independently is shown to be able to approximate mask topography induced diffraction for both polarizations with 5-10nm wide boundary layers.

  13. A Novel Segmentation Approach Combining Region- and Edge-Based Information for Ultrasound Images.

    PubMed

    Luo, Yaozhong; Liu, Longzhong; Huang, Qinghua; Li, Xuelong

    2017-01-01

    Ultrasound imaging has become one of the most popular medical imaging modalities with numerous diagnostic applications. However, ultrasound (US) image segmentation, which is the essential process for further analysis, is a challenging task due to the poor image quality. In this paper, we propose a new segmentation scheme to combine both region- and edge-based information into the robust graph-based (RGB) segmentation method. The only interaction required is to select two diagonal points to determine a region of interest (ROI) on the original image. The ROI image is smoothed by a bilateral filter and then contrast-enhanced by histogram equalization. Then, the enhanced image is filtered by pyramid mean shift to improve homogeneity. With the optimization of particle swarm optimization (PSO) algorithm, the RGB segmentation method is performed to segment the filtered image. The segmentation results of our method have been compared with the corresponding results obtained by three existing approaches, and four metrics have been used to measure the segmentation performance. The experimental results show that the method achieves the best overall performance and gets the lowest ARE (10.77%), the second highest TPVF (85.34%), and the second lowest FPVF (4.48%).

  14. Edge-preserving image denoising via group coordinate descent on the GPU

    PubMed Central

    McGaffin, Madison G.; Fessler, Jeffrey A.

    2015-01-01

    Image denoising is a fundamental operation in image processing, and its applications range from the direct (photographic enhancement) to the technical (as a subproblem in image reconstruction algorithms). In many applications, the number of pixels has continued to grow, while the serial execution speed of computational hardware has begun to stall. New image processing algorithms must exploit the power offered by massively parallel architectures like graphics processing units (GPUs). This paper describes a family of image denoising algorithms well-suited to the GPU. The algorithms iteratively perform a set of independent, parallel one-dimensional pixel-update subproblems. To match GPU memory limitations, they perform these pixel updates inplace and only store the noisy data, denoised image and problem parameters. The algorithms can handle a wide range of edge-preserving roughness penalties, including differentiable convex penalties and anisotropic total variation (TV). Both algorithms use the majorize-minimize (MM) framework to solve the one-dimensional pixel update subproblem. Results from a large 2D image denoising problem and a 3D medical imaging denoising problem demonstrate that the proposed algorithms converge rapidly in terms of both iteration and run-time. PMID:25675454

  15. Edge-preserving image denoising via group coordinate descent on the GPU.

    PubMed

    McGaffin, Madison Gray; Fessler, Jeffrey A

    2015-04-01

    Image denoising is a fundamental operation in image processing, and its applications range from the direct (photographic enhancement) to the technical (as a subproblem in image reconstruction algorithms). In many applications, the number of pixels has continued to grow, while the serial execution speed of computational hardware has begun to stall. New image processing algorithms must exploit the power offered by massively parallel architectures like graphics processing units (GPUs). This paper describes a family of image denoising algorithms well-suited to the GPU. The algorithms iteratively perform a set of independent, parallel 1D pixel-update subproblems. To match GPU memory limitations, they perform these pixel updates in-place and only store the noisy data, denoised image, and problem parameters. The algorithms can handle a wide range of edge-preserving roughness penalties, including differentiable convex penalties and anisotropic total variation. Both algorithms use the majorize-minimize framework to solve the 1D pixel update subproblem. Results from a large 2D image denoising problem and a 3D medical imaging denoising problem demonstrate that the proposed algorithms converge rapidly in terms of both iteration and run-time.

  16. Polarimetric investigation of edge scattering by mono- and bistatic microwave imaging

    NASA Astrophysics Data System (ADS)

    Herdeg, Wolfgang

    1991-07-01

    The scattering of electromagnetic waves from edges is investigated with regard to frequency, aspect angle, polarization, and bistatic angle. The edges of simple metal objects (cubes, plates, and wedges) are resolved in range and cross range using a high resolution microwave imaging process and are investigated as canonical structures. The Geometrical Theory of Diffraction (GTD) is used as a theoretical model. The scattering coefficients of GTD are compared with experiment. The polarimetric results are presented using the Hymen parameters. Microwave mirrors, which are large metal plates which reflect the bistatic scattering contribution to the monostatic radar, are introduced, in order to carry out bistatic measurements on a monostatic radar range. Experimental results are in agreement with the proposed concepts.

  17. Reconstruction of accurate 3-D surfaces with sharp edges using digital structured light projection and multi-dimensional image fusion

    NASA Astrophysics Data System (ADS)

    Le, Manh-Trung; Chen, Liang-Chia; Lin, Chih-Jer

    2017-09-01

    The study presents a novel method that uses structured illumination imaging and data fusion to address one of the most difficult problems in 3-D optical measurement where an accurate 3-D sharp edge must be reconstructed, to allow automated inspection and reconstruction of a 3-D object. An innovative algorithm for reconstructing a 3-D surface profile with a sharp-edge boundary using multi-dimensional data fusion is proposed. An accurate 2-D surface edge is extracted from an image with high spatial-resolution, that is reconstructed using structured illumination imaging (SIM), so the projected edge contour of 2-D contour along the optical imaging axis can be accurately determined. The neighboring surface between the 2-D detected edge and the identified 3-D surface contour is reconstructed by extrapolating the surface using NURBS surface fitting to detect the intersecting edges. Experiments are performed to confirm the feasibility, effectiveness and accuracy of the developed method and there is a comparison between the results for a reconstructed 3-D sharp edge and a pre-calibrated high precision instrument. The proposed method ensures that a maximum deviation between the reference target and the reconstructed critical dimension is 3 μm so a resolution for the optical imaging system of less than 0.5 pixel can be achieved. The experimental results demonstrate that the proposed method is both effective and accurate.

  18. Photon counting x-ray imaging with K-edge filtered x-rays: A simulation study.

    PubMed

    Atak, Haluk; Shikhaliev, Polad M

    2016-03-01

    In photon counting (PC) x-ray imaging and computed tomography (CT), the broad x-ray spectrum can be split into two parts using an x-ray filter with appropriate K-edge energy, which can improve material decomposition. Recent experimental study has demonstrated substantial improvement in material decomposition with PC CT when K-edge filtered x-rays were used. The purpose of the current work was to conduct further investigations of the K-edge filtration method using comprehensive simulation studies. The study was performed in the following aspects: (1) optimization of the K-edge filter for a particular imaging configuration, (2) effects of the K-edge filter parameters on material decomposition, (3) trade-off between the energy bin separation, tube load, and beam quality with K-edge filter, (4) image quality of general (unsubtracted) images when a K-edge filter is used to improve dual energy (DE) subtracted images, and (5) improvements with K-edge filtered x-rays when PC detector has limited energy resolution. The PC x-ray images of soft tissue phantoms with 15 and 30 cm thicknesses including iodine, CaCO3, and soft tissue contrast materials, were simulated. The signal to noise ratio (SNR) of the contrast elements was determined in general and material-decomposed images using K-edge filters with different atomic numbers and thicknesses. The effect of the filter atomic number and filter thickness on energy separation factor and SNR was determined. The boundary conditions for the tube load and halfvalue layer were determined when the K-edge filters are used. The material-decomposed images were also simulated using PC detector with limited energy resolution, and improvements with K-edge filtered x-rays were quantified. The K-edge filters with atomic numbers from 56 to 71 and K-edge energies 37.4-63.4 keV, respectively, can be used for tube voltages from 60 to 150 kVp, respectively. For a particular tube voltage of 120 kVp, the Gd and Ho were the optimal filter materials

  19. Edge effects in a small pixel CdTe for X-ray imaging

    NASA Astrophysics Data System (ADS)

    Duarte, D. D.; Bell, S. J.; Lipp, J.; Schneider, A.; Seller, P.; Veale, M. C.; Wilson, M. D.; Baker, M. A.; Sellin, P. J.; Kachkanov, V.; Sawhney, K. J. S.

    2013-10-01

    Large area detectors capable of operating with high detection efficiency at energies above 30 keV are required in many contemporary X-ray imaging applications. The properties of high Z compound semiconductors, such as CdTe, make them ideally suitable to these applications. The STFC Rutherford Appleton Laboratory has developed a small pixel CdTe detector with 80 × 80 pixels on a 250 μm pitch. Historically, these detectors have included a 200 μm wide guard band around the pixelated anode to reduce the effect of defects in the crystal edge. The latest version of the detector ASIC is capable of four-side butting that allows the tiling of N × N flat panel arrays. To limit the dead space between modules to the width of one pixel, edgeless detector geometries have been developed where the active volume of the detector extends to the physical edge of the crystal. The spectroscopic performance of an edgeless CdTe detector bump bonded to the HEXITEC ASIC was tested with sealed radiation sources and compared with a monochromatic X-ray micro-beam mapping measurements made at the Diamond Light Source, U.K. The average energy resolution at 59.54 keV of bulk and edge pixels was 1.23 keV and 1.58 keV, respectively. 87% of the edge pixels present fully spectroscopic performance demonstrating that edgeless CdTe detectors are a promising technology for the production of large panel radiation detectors for X-ray imaging.

  20. A single-image retrieval method for edge illumination X-ray phase-contrast imaging: Application and noise analysis.

    PubMed

    Diémoz, Paul C; Vittoria, Fabio A; Hagen, Charlotte K; Endrizzi, Marco; Coan, Paola; Bravin, Alberto; Wagner, Ulrich H; Rau, Christoph; Robinson, Ian K; Olivo, Alessandro

    2016-12-01

    Edge illumination (EI) X-ray phase-contrast imaging (XPCI) has been under development at University College London in recent years, and has shown great potential for both laboratory and synchrotron applications. In this work, we propose a new acquisition and processing scheme. Contrary to existing retrieval methods for EI, which require as input two images acquired in different setup configurations, the proposed approach can retrieve an approximate map of the X-ray phase from a single image, thus significantly simplifying the acquisition procedure and reducing data collection times. The retrieval method is analytically derived, based on the assumption of a quasi-homogeneous object, i.e. an object featuring a constant ratio between refractive index and absorption coefficient. The noise properties of the input and retrieved images are also theoretically analyzed under the developed formalism. The method is applied to experimental synchrotron images of a biological object. The experimental results show that the method can provide high-quality images, where the "edge" signal typical of XPCI images is transformed to an "area" contrast that enables an easier interpretation of the sample geometry. Moreover, the retrieved images confirm that the method is highly stable against noise. We anticipate that the developed approach will become the method of choice for a variety of applications of EI XPCI, thanks to its ability to simplify the acquisition procedure and reduce acquisitions time and dose to the sample. Future work will focus on the adaptation of the method to computed tomography and to polychromatic radiation from X-ray tubes. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. Surface phenomena revealed by in situ imaging: studies from adhesion, wear and cutting

    NASA Astrophysics Data System (ADS)

    Viswanathan, Koushik; Mahato, Anirban; Yeung, Ho; Chandrasekar, Srinivasan

    2017-03-01

    Surface deformation and flow phenomena are ubiquitous in mechanical processes. In this work we present an in situ imaging framework for studying a range of surface mechanical phenomena at high spatial resolution and across a range of time scales. The in situ framework is capable of resolving deformation and flow fields quantitatively in terms of surface displacements, velocities, strains and strain rates. Three case studies are presented demonstrating the power of this framework for studying surface deformation. In the first, the origin of stick-slip motion in adhesive polymer interfaces is investigated, revealing a intimate link between stick-slip and surface wave propagation. Second, the role of flow in mediating formation of surface defects and wear particles in metals is analyzed using a prototypical sliding process. It is shown that conventional post-mortem observation and inference can lead to erroneous conclusions with regard to formation of surface cracks and wear particles. The in situ framework is shown to unambiguously capture delamination wear in sliding. Third, material flow and surface deformation in a typical cutting process is analyzed. It is shown that a long-standing problem in the cutting of annealed metals is resolved by the imaging, with other benefits such as estimation of energy dissipation and power from the flow fields. In closure, guidelines are provided for profitably exploiting in situ observations to study large-strain deformation, flow and friction phenomena at surfaces that display a variety of time-scales.

  2. Automatic segmentation of nerve structures in ultrasound images using Graph Cuts and Gaussian processes.

    PubMed

    Gil González, Julián; Álvarez, Mauricio A; Orozco, Álvaro A

    2015-01-01

    Peripheral Nerve Blocking (PNB), is a procedure used for performing regional anesthesia, that comprises the administration of anesthetic in the proximity of a nerve. Several techniques have been used with the purpose of locating nerve structures when the PNB procedure is performed: anatomical surface landmarks, elicitation of paresthesia, nerve stimulation and ultrasound imaging. Among those, ultrasound imaging has gained great attention because it is not invasive and offers an accurate location of the nerve and the structures around it. However, the segmentation of nerve structures in ultrasound images is a difficult task for the specialist, since such images are affected by echo perturbations and speckle noise. The development of systems for the automatic segmentation of nerve structures can aid the specialist for locating nerve structures accurately. In this paper we present a methodology for the automatic segmentation of nerve structures in ultrasound images. An initial step is carried out using Graph Cut segmentation in order to generate regions of interest; we then use machine learning techniques with the aim of segmenting the nerve structure; here, a specific non-linear Wavelet transform is used for the feature extraction stage, and Gaussian processes for the classification step. The methodology performance is measured in terms of accuracy and the dice coefficient. Results show that the implemented methodology can be used for automatically segmenting nerve structures.

  3. Edge-illumination x-ray phase contrast imaging with Pt-based metallic glass masks

    NASA Astrophysics Data System (ADS)

    Saghamanesh, Somayeh; Aghamiri, Seyed Mahmoud-Reza; Olivo, Alessandro; Sadeghilarijani, Maryam; Kato, Hidemi; Kamali-Asl, Alireza; Yashiro, Wataru

    2017-06-01

    Edge-illumination x-ray phase contrast imaging (EI XPCI) is a non-interferometric phase-sensitive method where two absorption masks are employed. These masks are fabricated through a photolithography process followed by electroplating which is challenging in terms of yield as well as time- and cost-effectiveness. We report on the first implementation of EI XPCI with Pt-based metallic glass masks fabricated by an imprinting method. The new tested alloy exhibits good characteristics including high workability beside high x-ray attenuation. The fabrication process is easy and cheap, and can produce large-size masks for high x-ray energies within minutes. Imaging experiments show a good quality phase image, which confirms the potential of these masks to make the EI XPCI technique widely available and affordable.

  4. Dual transmission grating based imaging radiometer for tokamak edge and divertor plasmas

    SciTech Connect

    Kumar, Deepak; Clayton, Daniel J.; Parman, Matthew; Stutman, Dan; Tritz, Kevin; Finkenthal, Michael

    2012-10-15

    The designs of single transmission grating based extreme ultraviolet (XUV) and vacuum ultraviolet (VUV) imaging spectrometers can be adapted to build an imaging radiometer for simultaneous measurement of both spectral ranges. This paper describes the design of such an imaging radiometer with dual transmission gratings. The radiometer will have an XUV coverage of 20-200 A with a {approx}10 A resolution and a VUV coverage of 200-2000 A with a {approx}50 A resolution. The radiometer is designed to have a spatial view of 16 Degree-Sign , with a 0.33 Degree-Sign resolution and a time resolution of {approx}10 ms. The applications for such a radiometer include spatially resolved impurity monitoring and electron temperature measurements in the tokamak edge and the divertor. As a proof of principle, the single grating instruments were used to diagnose a low temperature reflex discharge and the relevant data is also included in this paper.

  5. Plasma image edge detection based on the visible camera in the EAST device.

    PubMed

    Shu, Shuangbao; Xu, Chongyang; Chen, Meiwen; Yang, Zhendong

    2016-01-01

    The controlling of plasma shape and position are essential to the success of Tokamak discharge. A real-time image acquisition system was designed to obtain plasma radiation image during the discharge processes in the Experimental Advanced Superconducting Tokamak (EAST) device. The hardware structure and software design of this visible camera system are introduced in detail. According to the general structure of EAST and the layout of the observation window, spatial location of the discharging plasma in the image was measured. An improved Sobel edge detection algorithm using iterative threshold was proposed to detect plasma boundary. EAST discharge results show that the proposed method acquired plasma position and boundary with high accuracy, which is of great significance for better plasma control.

  6. Post-processing noise removal algorithm for magnetic resonance imaging based on edge detection and wavelet analysis.

    PubMed

    Placidi, Giuseppe; Alecci, Marcello; Sotgiu, Antonello

    2003-07-07

    A post-processing noise suppression technique for biomedical MRI images is presented. The described procedure recovers both sharp edges and smooth surfaces from a given noisy MRI image; it does not blur the edges and does not introduce spikes or other artefacts. The fine details of the image are also preserved. The proposed algorithm first extracts the edges from the original image and then performs noise reduction by using a wavelet de-noise method. After the application of the wavelet method, the edges are restored to the filtered image. The result is the original image with less noise, fine detail and sharp edges. Edge extraction is performed by using an algorithm based on Sobel operators. The wavelet de-noise method is based on the calculation of the correlation factor between wavelet coefficients belonging to different scales. The algorithm was tested on several MRI images and, as an example of its application, we report the results obtained from a spin echo (multi echo) MRI image of a human wrist collected with a low field experimental scanner (the signal-to-noise ratio, SNR, of the experimental image was 12). Other filtering operations have been performed after the addition of white noise on both channels of the experimental image, before the magnitude calculation. The results at SNR = 7, SNR = 5 and SNR = 3 are also reported. For SNR values between 5 and 12, the improvement in SNR was substantial and the fine details were preserved, the edges were not blurred and no spikes or other artefacts were evident, demonstrating the good performances of our method. At very low SNR (SNR = 3) our result is worse than that obtained by a simpler filtering procedure.

  7. Post-processing noise removal algorithm for magnetic resonance imaging based on edge detection and wavelet analysis

    NASA Astrophysics Data System (ADS)

    Placidi, Giuseppe; Alecci, Marcello; Sotgiu, Antonello

    2003-07-01

    A post-processing noise suppression technique for biomedical MRI images is presented. The described procedure recovers both sharp edges and smooth surfaces from a given noisy MRI image; it does not blur the edges and does not introduce spikes or other artefacts. The fine details of the image are also preserved. The proposed algorithm first extracts the edges from the original image and then performs noise reduction by using a wavelet de-noise method. After the application of the wavelet method, the edges are restored to the filtered image. The result is the original image with less noise, fine detail and sharp edges. Edge extraction is performed by using an algorithm based on Sobel operators. The wavelet de-noise method is based on the calculation of the correlation factor between wavelet coefficients belonging to different scales. The algorithm was tested on several MRI images and, as an example of its application, we report the results obtained from a spin echo (multi echo) MRI image of a human wrist collected with a low field experimental scanner (the signal-to-noise ratio, SNR, of the experimental image was 12). Other filtering operations have been performed after the addition of white noise on both channels of the experimental image, before the magnitude calculation. The results at SNR = 7, SNR = 5 and SNR = 3 are also reported. For SNR values between 5 and 12, the improvement in SNR was substantial and the fine details were preserved, the edges were not blurred and no spikes or other artefacts were evident, demonstrating the good performances of our method. At very low SNR (SNR = 3) our result is worse than that obtained by a simpler filtering procedure.

  8. Evaluation of an edge method for computed radiography and an electronic portal imaging device in radiotherapy: Image quality measurements

    NASA Astrophysics Data System (ADS)

    Son, Soon-Yong; Choe, Bo-Young; Lee, Jeong-Woo; Kim, Jung-Min; Jeong, Hoi-Woun; Kim, Ham-Gyum; Kim, Wha-Sun; Lyu, Kwang-Yeul; Min, Jung-Whan; Kim, Ki-Won

    2014-12-01

    Regular quality assurance (QA) of image quality is essential for reasonable patient dose and accurate treatment. Thus, QA should be performed as a routine for correction. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) of the computed radiography (CR) system and the digital radiography (DR) system by using the edge method in megavoltage X-ray imaging (MVI). We used an edge block, which consisting of tungsten with dimensions of 19 (thickness) × 10 (length) × 1 (width) cm3 and measured the pre-sampling MTF by using a 6-megavolt (MV) energy. Computed radiography with an image plate (CR-IP) showed the values of 0.4 mm-1 and 1.19 mm-1 for MTF 0.5 and 0.1. In the DR group, Elekta iViewGT showed the highest value of 0.27 mm-1 for MTF 0.5, and Siemens BEAMVIEW PLUS showed the highest value of 0.98 mm-1 for MTF 0.1. In CR, the NPS of CR-IP showed a favorable noise distribution. Thus, in the DR group, the NPS of Elekta iViewGT showed the highest noise distribution. CR-IP showed values at peak DQE and 1 mm-1 DQE of 0.0013 and 0.00011, respectively. In the DR group, Elekta iViewGT showed the best efficiency at a peak DQE of 0.0009, and Siemens BEAMVIEW PLUS showed the best efficiency at a 1-mm-1 DQE of 0.000008. The edge method produced fast assessments of the MTF and the DQE. We could validate the evaluation of the edge method by comparing of the CR system to the DR system. This study demonstrated that the edge method can be used for not only traditional QA imaging but also quantitative MTF, NPS and DQE measurements in detector development.

  9. Few-photon color imaging using energy-dispersive superconducting transition-edge sensor spectrometry

    PubMed Central

    Niwa, Kazuki; Numata, Takayuki; Hattori, Kaori; Fukuda, Daiji

    2017-01-01

    Highly sensitive spectral imaging is increasingly being demanded in bioanalysis research and industry to obtain the maximum information possible from molecules of different colors. We introduce an application of the superconducting transition-edge sensor (TES) technique to highly sensitive spectral imaging. A TES is an energy-dispersive photodetector that can distinguish the wavelength of each incident photon. Its effective spectral range is from the visible to the infrared (IR), up to 2800 nm, which is beyond the capabilities of other photodetectors. TES was employed in this study in a fiber-coupled optical scanning microscopy system, and a test sample of a three-color ink pattern was observed. A red–green–blue (RGB) image and a near-IR image were successfully obtained in the few-incident-photon regime, whereas only a black and white image could be obtained using a photomultiplier tube. Spectral data were also obtained from a selected focal area out of the entire image. The results of this study show that TES is feasible for use as an energy-dispersive photon-counting detector in spectral imaging applications. PMID:28374801

  10. Few-photon color imaging using energy-dispersive superconducting transition-edge sensor spectrometry.

    PubMed

    Niwa, Kazuki; Numata, Takayuki; Hattori, Kaori; Fukuda, Daiji

    2017-04-04

    Highly sensitive spectral imaging is increasingly being demanded in bioanalysis research and industry to obtain the maximum information possible from molecules of different colors. We introduce an application of the superconducting transition-edge sensor (TES) technique to highly sensitive spectral imaging. A TES is an energy-dispersive photodetector that can distinguish the wavelength of each incident photon. Its effective spectral range is from the visible to the infrared (IR), up to 2800 nm, which is beyond the capabilities of other photodetectors. TES was employed in this study in a fiber-coupled optical scanning microscopy system, and a test sample of a three-color ink pattern was observed. A red-green-blue (RGB) image and a near-IR image were successfully obtained in the few-incident-photon regime, whereas only a black and white image could be obtained using a photomultiplier tube. Spectral data were also obtained from a selected focal area out of the entire image. The results of this study show that TES is feasible for use as an energy-dispersive photon-counting detector in spectral imaging applications.

  11. Subjective and objective evaluation of image sharpness: behavior of the region-based image edge profile acutance measure

    NASA Astrophysics Data System (ADS)

    Delgado-Olabarriaga, Silvia; Rangayyan, Rangaraj M.

    1996-03-01

    We recently proposed a region-based measure of image edge profile acutance to characterize the sharpness of a region of interest. In this paper we study the capability of the acutance measure to analyze relative sharpness in the presence of blurring and noise by comparing acutance to other measures of distortion and to subjective evaluation. The purpose of the experiment was to organize an image set in increasing order of sharpness with results obtained by objective image quality measures (acutance, mean squared error, normalized error, and normalized mean squared error) and to compare the results with subjective evaluation. A psychometric experiment was developed to perform sorting according to the subjective notion of sharpness. The region-based image edge profile acutance measure provided results that agree more closely with subjective evaluation of relative sharpness than the other measures studied. The acutance measure also exhibited a good level of immunity to noise, whereas the other measures provided ordering according to noise rather than sharpness.

  12. Building on the Cutting Edge

    ERIC Educational Resources Information Center

    Wong, Wylie

    2007-01-01

    Administrators of today's community college are sprucing up facilities with new amenities and services to attract students and cater to their needs. Administrators say competition for students is fierce and that good facilities can make a big difference when students are deciding on which school to attend. While students cite academic quality as…

  13. Moving beyond the Cutting Edge.

    ERIC Educational Resources Information Center

    Chaffe, Robert F.

    Following a nationwide drought in 1982, the Australian government instituted the National Property Management Planning program to build skills in the rural community to better manage the farm business, including the need to manage change. In Victoria, the program is delivered through the Farm$mart project. Farm$mart is: learner centered; involves…

  14. Alternative Education: The Cutting Edge?

    ERIC Educational Resources Information Center

    Byrne, Jay

    2004-01-01

    Miami Valley Career Technology Youth Connections, an alternative high school located in Dayton, Ohio, has an enrollment of 160 students and was created as a joint venture among local politicians to address the high dropout rates in Montgomery County, Ohio. To achieve this, the Montgomery County commissioners created a task force to develop…

  15. Alternative Education: The Cutting Edge?

    ERIC Educational Resources Information Center

    Byrne, Jay

    2004-01-01

    Miami Valley Career Technology Youth Connections, an alternative high school located in Dayton, Ohio, has an enrollment of 160 students and was created as a joint venture among local politicians to address the high dropout rates in Montgomery County, Ohio. To achieve this, the Montgomery County commissioners created a task force to develop…

  16. A Bremsstrahlung Spectrometer using k-edge and Differential Filters with Image plate dosimeters

    SciTech Connect

    Chen, C; Mackinnon, A; Beg, F; Chen, H; Key, M; King, J A; Link, A; MacPhee, A; Patel, P; Porkolab, M; Stephens, R; VanWoerkom, L; Akli, K; Freeman, R

    2008-05-02

    A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with Image Plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code Integrated Tiger Series 3.0 and the dosimeters calibrated with radioactive sources. Electron distributions with slope temperatures in the MeV range are inferred from the Bremsstrahlung spectra.

  17. A Bremsstrahlung spectrometer using k-edge and differential filters with image plate dosimeters

    SciTech Connect

    Chen, C. D.; Porkolab, M.; King, J. A.; Beg, F. N.; Key, M. H.; Chen, H.; Mackinnon, A. J.; MacPhee, A. G.; Patel, P. K.; Akli, K. U.; Stephens, R. B.; Freeman, R. R.; Link, A.; Van Woerkom, L. D.

    2008-10-15

    A Bremsstrahlung spectrometer using k-edge and differential filtering has been used with image plate dosimeters to measure the x-ray fluence from short-pulse laser/target interactions. An electron spectrometer in front of the Bremsstrahlung spectrometer deflects electrons from the x-ray line of sight and simultaneously measures the electron spectrum. The response functions were modeled with the Monte Carlo code INTEGRATED TIGER SERIES 3.0 and the dosimeters calibrated with radioactive sources. An electron distribution with a slope temperature of 1.3 MeV is inferred from the Bremsstrahlung spectra.

  18. Sensitivity of photon-counting based K-edge imaging in X-ray computed tomography.

    PubMed

    Roessl, Ewald; Brendel, Bernhard; Engel, Klaus-Jürgen; Schlomka, Jens-Peter; Thran, Axel; Proksa, Roland

    2011-09-01

    The feasibility of K-edge imaging using energy-resolved, photon-counting transmission measurements in X-ray computed tomography (CT) has been demonstrated by simulations and experiments. The method is based on probing the discontinuities of the attenuation coefficient of heavy elements above and below the K-edge energy by using energy-sensitive, photon counting X-ray detectors. In this paper, we investigate the dependence of the sensitivity of K-edge imaging on the atomic number Z of the contrast material, on the object diameter D , on the spectral response of the X-ray detector and on the X-ray tube voltage. We assume a photon-counting detector equipped with six adjustable energy thresholds. Physical effects leading to a degradation of the energy resolution of the detector are taken into account using the concept of a spectral response function R(E,U) for which we assume four different models. As a validation of our analytical considerations and in order to investigate the influence of elliptically shaped phantoms, we provide CT simulations of an anthropomorphic Forbild-Abdomen phantom containing a gold-contrast agent. The dependence on the values of the energy thresholds is taken into account by optimizing the achievable signal-to-noise ratios (SNR) with respect to the threshold values. We find that for a given X-ray spectrum and object size the SNR in the heavy element's basis material image peaks for a certain atomic number Z. The dependence of the SNR in the high- Z basis-material image on the object diameter is the natural, exponential decrease with particularly deteriorating effects in the case where the attenuation from the object itself causes a total signal loss below the K-edge. The influence of the energy-response of the detector is very important. We observed that the optimal SNR values obtained with an ideal detector and with a CdTe pixel detector whose response, showing significant tailing, has been determined at a synchrotron differ by factors of

  19. Efficient liver segmentation in CT images based on graph cuts and bottleneck detection.

    PubMed

    Liao, Miao; Zhao, Yu-Qian; Wang, Wei; Zeng, Ye-Zhan; Yang, Qing; Shih, Frank Y; Zou, Bei-Ji

    2016-11-01

    Liver segmentation from abdominal computed tomography (CT) volumes is extremely important for computer-aided liver disease diagnosis and surgical planning of liver transplantation. Due to ambiguous edges, tissue adhesion, and variation in liver intensity and shape across patients, accurate liver segmentation is a challenging task. In this paper, we present an efficient semi-automatic method using intensity, local context, and spatial correlation of adjacent slices for the segmentation of healthy liver regions in CT volumes. An intensity model is combined with a principal component analysis (PCA) based appearance model to exclude complex background and highlight liver region. They are then integrated with location information from neighboring slices into graph cuts to segment the liver in each slice automatically. Finally, a boundary refinement method based on bottleneck detection is used to increase the segmentation accuracy. Our method does not require heavy training process or statistical model construction, and is capable of dealing with complicated shape and intensity variations. We apply the proposed method on XHCSU14 and SLIVER07 databases, and evaluate it by MICCAI criteria and Dice similarity coefficient. Experimental results show our method outperforms several existing methods on liver segmentation.

  20. Upgrade to the Gas Puff Imaging Diagnostic that Views Alcator C-Mod's Inboard Edge

    NASA Astrophysics Data System (ADS)

    Sierchio, J. M.; Terry, J. L.

    2012-10-01

    We describe an upgrade of Alcator C-Mod's Gas Puff Imaging system which views the inboard plasma edge and SOL along lines-of-sight that are approximately parallel to the local magnetic field. The views are arranged in a 2D (R,Z) array with ˜2.8 cm radial coverage and ˜2.4 cm poloidal coverage. 23 of 54 available views were coupled via fibers to individual interference filters and PIN photodiode detectors. We are in the process of upgrading the system in order to increase the sensitivity of the system by replacing the PIN photodiodes with a 4x8 array of Avalanche Photo-Diodes (APD). Light from 30 views is coupled to the single-chip APD array through a single interference filter. We expect an improvement in signal-to-noise ratio of more than 10x. The frequency response of the system will increase from ˜400 kHz to 1MHz. The dynamic range of the new system is manipulated by changing the high-voltages on the APDs. Test results of the detectors' channel-to-channel cross-talk, frequency response, and gain curves will be presented, along with schematics of the experimental setup. The upgraded system allows for more study of inboard edge fluctuations, including whether the quasi-coherent fluctuations observed in the outboard edge also exist inboard.

  1. Blob birth and transport in the tokamak edge plasma: Analysis of imaging data

    SciTech Connect

    Myra, J. R.; D'Ippolito, D. A.; Stotler, D. P.; Zweben, S. J.; LeBlanc, B. P.; Menard, J. E.; Maqueda, R. J.; Boedo, J.

    2006-09-15

    High-speed high-spatial-resolution data obtained by the gas puff imaging (GPI) diagnostic on the National Spherical Torus Experiment [M. Ono, M.G. Bell, R.E. Bell et al. Plasma Phys. Control. Fusion 45, A335 (2003).] is analyzed and interpreted in light of recent theoretical models for electrostatic edge turbulence and blob propagation. The experiment is described in terms of theoretical regimes that predict different dependencies for the radial velocity of blob convection. Using the GPI data, atomic physics analysis, and blob tracking on a restricted dataset, it is shown that the observed blob velocities in the scrape-off layer are bounded by a theory-based minimum velocity associated with the sheath-connected regime. A similar maximum velocity bound associated with the resistive-ballooning regime is also observed. Turning to the question of blob creation, it is shown that blobs are born with a density and temperature characteristic of the plasma conditions where underlying linear edge drift-curvature instabilities are localized. Finally, statistical variations in blob properties and in the radial blob velocity for given edge conditions are significant, and tend to mask any systematic changes among discharges with different conditions.

  2. Simultaneous reconstruction and edge detection of transmission images in emission computed tomography

    NASA Astrophysics Data System (ADS)

    Lee, Soo-Jin

    2001-12-01

    This paper presents a Bayesian method for reconstructing transmission images, which provide attenuation correction factors for emission scans. In order to preserve the edges that bound anatomical regions, which are important especially for areas of non-uniform attenuation, we use the line-process model as a prior. Our prior model provides edge maps containing the anatomical boundary information as well as edge preserved reconstructions. To optimize our nonconvex objective function, we use our previously developed deterministic annealing algorithm, in which the energy function is approximated by a sequence of smooth functions that converges uniformly to the original energy function. To accelerate the convergence speed of our algorithm, we apply the ordered subsets principle to the deterministic annealing algorithm. We also show how the smoothing parameter can be adjusted to account for the effects of using ordered subsets so that the degree of smoothness can be retained for variations of the number of subsets. To validate the quantitative performance of our algorithm, we use the quantitation of bias/variance over noise trials. Our preliminary results indicate that, in some circumstances, our methods have advantages over conventional methods.

  3. Automated detection of buildings from single VHR multispectral images using shadow information and graph cuts

    NASA Astrophysics Data System (ADS)

    Ok, Ali Ozgun

    2013-12-01

    In this study, we propose a novel methodology for automated detection of buildings from single very-high-resolution (VHR) multispectral images. The methodology uses the principal evidence of buildings: the shadows that they cast. We model the directional spatial relationship between buildings and their shadows using a recently proposed probabilistic landscape approach. An effective shadow post-processing step is developed to focus on landscapes that belong to building regions. The building regions are detected using an original two-level graph theory approach. In the first level, each shadow region is addressed separately, and building regions are identified via iterative graph cuts designed in two-label partitioning. The final building regions are characterised in a second level in which the previously labelled building regions are subjected to a single-step multi-label graph optimisation performed over the entire image domain. Numerical assessments performed on 16 VHR GeoEye-1 images demonstrate that the proposed approach is highly robust and reliable. A distinctive specialty of the proposed approach is its applicability to buildings with diverse characteristics as well as to VHR images with significantly different illumination properties.

  4. Reconstruction of binary geological images using analytical edge and object models

    NASA Astrophysics Data System (ADS)

    Abdollahifard, Mohammad J.; Ahmadi, Sadegh

    2016-04-01

    Reconstruction of fields using partial measurements is of vital importance in different applications in geosciences. Solving such an ill-posed problem requires a well-chosen model. In recent years, training images (TI) are widely employed as strong prior models for solving these problems. However, in the absence of enough evidence it is difficult to find an adequate TI which is capable of describing the field behavior properly. In this paper a very simple and general model is introduced which is applicable to a fairly wide range of binary images without any modifications. The model is motivated by the fact that nearly all binary images are composed of simple linear edges in micro-scale. The analytic essence of this model allows us to formulate the template matching problem as a convex optimization problem having efficient and fast solutions. The model has the potential to incorporate the qualitative and quantitative information provided by geologists. The image reconstruction problem is also formulated as an optimization problem and solved using an iterative greedy approach. The proposed method is capable of recovering the image unknown values with accuracies about 90% given samples representing as few as 2% of the original image.

  5. Graph cut based co-segmentation of lung tumor in PET-CT images

    NASA Astrophysics Data System (ADS)

    Ju, Wei; Xiang, Dehui; Zhang, Bin; Chen, Xinjian

    2015-03-01

    Accurate segmentation of pulmonary tumor is important for clinicians to make appropriate diagnosis and treatment. Positron Emission Tomography (PET) and Computed Tomography (CT) are two commonly used imaging technologies for image-guided radiation therapy. In this study, we present a graph-based method to integrate the two modalities to segment the tumor simultaneously on PET and CT images. The co-segmentation problem is formulated as an energy minimization problem. Two weighted sub-graphs are constructed for PET and CT. The characteristic information of the two modalities is encoded on the edges of the graph. A context cost is enforced by adding context arcs to achieve consistent results between the two modalities. An optimal solution can be achieved by solving a maximum flow problem. The proposed segmentation method was validated on 18 sets of PET-CT images from different patients with non-small cell lung cancer (NSCLC). The quantitative results show significant improvement of our method with a mean DSC value 0.82.

  6. Edge preserving smoothing and segmentation of 4-D images via transversely isotropic scale-space processing and fingerprint analysis

    SciTech Connect

    Reutter, Bryan W.; Algazi, V. Ralph; Gullberg, Grant T; Huesman, Ronald H.

    2004-01-19

    Enhancements are described for an approach that unifies edge preserving smoothing with segmentation of time sequences of volumetric images, based on differential edge detection at multiple spatial and temporal scales. Potential applications of these 4-D methods include segmentation of respiratory gated positron emission tomography (PET) transmission images to improve accuracy of attenuation correction for imaging heart and lung lesions, and segmentation of dynamic cardiac single photon emission computed tomography (SPECT) images to facilitate unbiased estimation of time-activity curves and kinetic parameters for left ventricular volumes of interest. Improved segmentation of lung surfaces in simulated respiratory gated cardiac PET transmission images is achieved with a 4-D edge detection operator composed of edge preserving 1-D operators applied in various spatial and temporal directions. Smoothing along the axis of a 1-D operator is driven by structure separation seen in the scale-space fingerprint, rather than by image contrast. Spurious noise structures are reduced with use of small-scale isotropic smoothing in directions transverse to the 1-D operator axis. Analytic expressions are obtained for directional derivatives of the smoothed, edge preserved image, and the expressions are used to compose a 4-D operator that detects edges as zero-crossings in the second derivative in the direction of the image intensity gradient. Additional improvement in segmentation is anticipated with use of multiscale transversely isotropic smoothing and a novel interpolation method that improves the behavior of the directional derivatives. The interpolation method is demonstrated on a simulated 1-D edge and incorporation of the method into the 4-D algorithm is described.

  7. "Crystals within Crystals: The Story of Sea Ice". A Classroom-Based Outreach Project Communicating Cutting-Edge Ocean Science to School Pupils

    NASA Astrophysics Data System (ADS)

    Butler, B.

    2016-02-01

    'Crystals within Crystals: The story of sea ice' is a UK based outreach project based that uses a range practical tools to engage school students with cutting edge scientific research that relates to the use of some of the world's most powerful X-rays in sea ice research. The project is delivered in the form of a classroom workshop that first introduces school pupils (aged 11-14) to seawater and the salts that give it a salinity. The pupils are then shown how the presence of salts within seawater results in very important physical changes when the liquid freezes, which includes different structural and optical properties of the ice. The properties of the ice are then linked to the presence of countless microscopic salt crystals that are trapped within the microstructure of the frozen seawater, which is explained with use of a novel crystal growth demonstration. Given that there is currently no way of successfully removing these salt crystals from the ice, the workshop culminates in explaining how some of the worlds most powerful X-rays can be used to investigate processes that otherwise remain elusive. The workshop introduces students to the fundamental principles of scientific enquiry, the sea ice environment, and the power of X-rays in investigating the properties of crystals. Here we present information that outlines a host of practical and project management tools that are applicacble to outreach projects in the the field of ocean sciences, with the aim of seeding ideas and interest for other graduate student to enage with the public during their studies.

  8. Outreach Aboard the JOIDES Resolution During IODP Exp. 360: Bringing Cutting Edge Research on Mid Ocean Ridge Processes to Classrooms Worldwide

    NASA Astrophysics Data System (ADS)

    Kavanagh, L.; Martinez, A. O.; Burgio, M.; Zhang, J.; Expedition 360 Scientists, I.

    2016-12-01

    In order to increase classroom engagement for the next generation of scientists, teachers must include current research in their curriculum. The JOIDES Resolution offers this opportunity to teachers worldwide. We recently served as four Education and Outreach Officers during Exp. 360: Southwest Indian Ridge Lower Crust and Moho. Our aim was to communicate the goals of the expedition to students and the general public through webcasts, social media, videos, and interviews. Prior to the expedition, I visited a number of schools in Texas and shared my upcoming experience with 800 teachers and students. Webcasts hosted during the expedition were tailored to the teacher's specifications of subject area and grade level. Students and teachers were able to witness cutting edge science during a tour of the ship and ask questions of those directly involved in the research. Lessons, resources, and videos featuring the scientific activities taking place and highlighting the workings of a research vessel were developed and will be featured at science teacher conferences at the state and national level. Upon my return home I visited schools that participated in webcasts and provided samples of peripheral rock material for instructional purposes. This expedition has also led to post cruise collaboration with some of the Expedition 360 scientists. My students will have the opportunity to do research with the microbiologists along the Rio Grande River and at Texas A&M University. Expedition 360 has opened up a multitude of opportunities for my students and those around the world that participated in the live webcasts. I was able to reach out to the same students multiple times during this experience which made it possible for them to connect with the science before, during, and after the expedition. These types of opportunities will inspire the next generation of scientists who will make advances towards new understandings of Earth's processes.

  9. Effect of antibrowning agents on fresh-cut potato tubers using frequency filtering of biospeckle images

    NASA Astrophysics Data System (ADS)

    Minz, Preeti D.; Zaheer Ansari, Md; Nirala, A. K.

    2015-04-01

    Our present work aims to study the physiological changes of chemically treated fresh-cut potato tubers and then to correlate such changes with the results of the non destructive and non invasive laser biospeckle technique. The effect of chemically treated (citric acid (CA-0.5% and 1.0%) and citric acid + sodium chloride (CS-0.5% and 1.0%)) fresh-cut potato tubers on physiological activities such as the respiration rate and weight loss at cold storage has been studied for eight consecutive days. In addition, biospeckle recording has been carried out for eight consecutive days for all the chemically treated samples and from captured images, and the numerical results (inertia moment (IM)) with and without frequency filtering have been obtained. A comparatively higher respiration rate and lower weight loss is observed for CS treated samples than that of CA treated samples. The results of the IM obtained with the exclusion of the higher frequency show a similar nature to the respiration rate and also, separations of the respiration curves at two concentrations for both the treated samples were well correlated with the IM curves. The concentration effect for both the treatments on the IM value with the exclusion of lower frequencies has also been presented. Thus the IM method with filtration of particular bands is able to separate the different physiological phenomena with one another and is also able to differentiate the chemical effect on the samples.

  10. An ordered-subsets proximal preconditioned gradient algorithm for edge-preserving PET image reconstruction.

    PubMed

    Mehranian, Abolfazl; Rahmim, Arman; Ay, Mohammad Reza; Kotasidis, Fotis; Zaidi, Habib

    2013-05-01

    In iterative positron emission tomography (PET) image reconstruction, the statistical variability of the PET data precorrected for random coincidences or acquired in sufficiently high count rates can be properly approximated by a Gaussian distribution, which can lead to a penalized weighted least-squares (PWLS) cost function. In this study, the authors propose a proximal preconditioned gradient algorithm accelerated with ordered subsets (PPG-OS) for the optimization of the PWLS cost function and develop a framework to incorporate boundary side information into edge-preserving total variation (TV) and Huber regularizations. The PPG-OS algorithm is proposed to address two issues encountered in the optimization of PWLS function with edge-preserving regularizers. First, the second derivative of this function (Hessian matrix) is shift-variant and ill-conditioned due to the weighting matrix (which includes emission data, attenuation, and normalization correction factors) and the regularizer. As a result, the paraboloidal surrogate functions (used in the optimization transfer techniques) end up with high curvatures and gradient-based algorithms take smaller step-sizes toward the solution, leading to a slow convergence. In addition, preconditioners used to improve the condition number of the problem, and thus to speed up the convergence, would poorly act on the resulting ill-conditioned Hessian matrix. Second, the PWLS function with a nondifferentiable penalty such as TV is not amenable to optimization using gradient-based algorithms. To deal with these issues and also to enhance edge-preservation of the TV and Huber regularizers by incorporating adaptively or anatomically derived boundary side information, the authors followed a proximal splitting method. Thereby, the optimization of the PWLS function is split into a gradient descent step (upgraded by preconditioning, step size optimization, and ordered subsets) and a proximal mapping associated with boundary weighted TV

  11. A continuous sampling scheme for edge illumination x-ray phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Hagen, C. K.; Coan, P.; Bravin, A.; Olivo, A.; Diemoz, P. C.

    2015-08-01

    We discuss an alternative acquisition scheme for edge illumination (EI) x-ray phase contrast imaging based on a continuous scan of the object and compare its performance to that of a previously used scheme, which involved scanning the object in discrete steps rather than continuously. By simulating signals for both continuous and discrete methods under realistic experimental conditions, the effect of the spatial sampling rate is analysed with respect to metrics such as image contrast and accuracy of the retrieved phase shift. Experimental results confirm the theoretical predictions. Despite being limited to a specific example, the results indicate that continuous schemes present advantageous features compared to discrete ones. Not only can they be used to speed up the acquisition but they also prove superior in terms of accurate phase retrieval. The theory and experimental results provided in this study will guide the design of future EI experiments through the implementation of optimized acquisition schemes and sampling rates.

  12. PISA: pixelwise image saliency by aggregating complementary appearance contrast measures with edge-preserving coherence.

    PubMed

    Wang, Keze; Lin, Liang; Lu, Jiangbo; Li, Chenglong; Shi, Keyang

    2015-10-01

    Driven by recent vision and graphics applications such as image segmentation and object recognition, computing pixel-accurate saliency values to uniformly highlight foreground objects becomes increasingly important. In this paper, we propose a unified framework called pixelwise image saliency aggregating (PISA) various bottom-up cues and priors. It generates spatially coherent yet detail-preserving, pixel-accurate, and fine-grained saliency, and overcomes the limitations of previous methods, which use homogeneous superpixel based and color only treatment. PISA aggregates multiple saliency cues in a global context, such as complementary color and structure contrast measures, with their spatial priors in the image domain. The saliency confidence is further jointly modeled with a neighborhood consistence constraint into an energy minimization formulation, in which each pixel will be evaluated with multiple hypothetical saliency levels. Instead of using global discrete optimization methods, we employ the cost-volume filtering technique to solve our formulation, assigning the saliency levels smoothly while preserving the edge-aware structure details. In addition, a faster version of PISA is developed using a gradient-driven image subsampling strategy to greatly improve the runtime efficiency while keeping comparable detection accuracy. Extensive experiments on a number of public data sets suggest that PISA convincingly outperforms other state-of-the-art approaches. In addition, with this work, we also create a new data set containing 800 commodity images for evaluating saliency detection.

  13. Optic disc detection in retinal fundus images using gravitational law-based edge detection.

    PubMed

    Alshayeji, Mohammad; Al-Roomi, Suood Abdulaziz; Abed, Sa'ed

    2017-06-01

    Diabetic retinopathy is one of the primary causes of vision loss worldwide. Early detection of the condition is critical for providing adequate treatment of this ailment to prevent vision loss. This detection is achieved by processing retinal fundus images. A key step in detecting diabetic retinopathy is identifying the optic disc in these images. The optic disc is similar in color and contrast to the exudates that indicate diabetic retinopathy. Hence, the optic disc has to be removed from the fundus image before exudates can be detected. Detecting the optic disc is also required in algorithms used for blood vessel segmentation in fundus images. Therefore, there is a need for approaches that accurately and quickly detect optic disc. This paper proposes a simple, deterministic, and time-efficient approach for optic disc detection by adapting an edge detection algorithm inspired by the gravitational law. Our method introduces novel pre- and post-detection steps that aim to increase the accuracy of the adapted detection method. In addition, a candidate selection technique is proposed to decrease the number of missed optic discs. The proposed methodology was found to have a detection rate of 100, 97.75, 92.90, and 95 % for DRIVE, DiaRet, DMED, and STARE datasets, respectively, which is comparatively better than existing optic disc detection schemes. Experimental results showed an average running time of 0.40 s per image, which is significantly lower than available methods published in the literature.

  14. Retinal image graph-cut segmentation algorithm using multiscale Hessian-enhancement-based nonlocal mean filter.

    PubMed

    Zheng, Jian; Lu, Pei-Rong; Xiang, Dehui; Dai, Ya-Kang; Liu, Zhao-Bang; Kuai, Duo-Jie; Xue, Hui; Yang, Yue-Tao

    2013-01-01

    We propose a new method to enhance and extract the retinal vessels. First, we employ a multiscale Hessian-based filter to compute the maximum response of vessel likeness function for each pixel. By this step, blood vessels of different widths are significantly enhanced. Then, we adopt a nonlocal mean filter to suppress the noise of enhanced image and maintain the vessel information at the same time. After that, a radial gradient symmetry transformation is adopted to suppress the nonvessel structures. Finally, an accurate graph-cut segmentation step is performed using the result of previous symmetry transformation as an initial. We test the proposed approach on the publicly available databases: DRIVE. The experimental results show that our method is quite effective.

  15. Multiscale registration of medical images based on edge preserving scale space with application in image-guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Li, Dengwang; Li, Hongsheng; Wan, Honglin; Chen, Jinhu; Gong, Guanzhong; Wang, Hongjun; Wang, Liming; Yin, Yong

    2012-08-01

    Mutual information (MI) is a well-accepted similarity measure for image registration in medical systems. However, MI-based registration faces the challenges of high computational complexity and a high likelihood of being trapped into local optima due to an absence of spatial information. In order to solve these problems, multi-scale frameworks can be used to accelerate registration and improve robustness. Traditional Gaussian pyramid representation is one such technique but it suffers from contour diffusion at coarse levels which may lead to unsatisfactory registration results. In this work, a new multi-scale registration framework called edge preserving multiscale registration (EPMR) was proposed based upon an edge preserving total variation L1 norm (TV-L1) scale space representation. TV-L1 scale space is constructed by selecting edges and contours of images according to their size rather than the intensity values of the image features. This ensures more meaningful spatial information with an EPMR framework for MI-based registration. Furthermore, we design an optimal estimation of the TV-L1 parameter in the EPMR framework by training and minimizing the transformation offset between the registered pairs for automated registration in medical systems. We validated our EPMR method on both simulated mono- and multi-modal medical datasets with ground truth and clinical studies from a combined positron emission tomography/computed tomography (PET/CT) scanner. We compared our registration framework with other traditional registration approaches. Our experimental results demonstrated that our method outperformed other methods in terms of the accuracy and robustness for medical images. EPMR can always achieve a small offset value, which is closer to the ground truth both for mono-modality and multi-modality, and the speed can be increased 5-8% for mono-modality and 10-14% for multi-modality registration under the same condition. Furthermore, clinical application by adaptive

  16. Discrimination methods for biological contaminants in fresh-cut lettuce based on VNIR and NIR hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Mo, Changyeun; Kim, Giyoung; Kim, Moon S.; Lim, Jongguk; Lee, Seung Hyun; Lee, Hong-Seok; Cho, Byoung-Kwan

    2017-09-01

    The rapid detection of biological contaminants such as worms in fresh-cut vegetables is necessary to improve the efficiency of visual inspections carried out by workers. Multispectral imaging algorithms were developed using visible-near-infrared (VNIR) and near-infrared (NIR) hyperspectral imaging (HSI) techniques to detect worms in fresh-cut lettuce. The optimal wavebands that can detect worms in fresh-cut lettuce were investigated for each type of HSI using one-way ANOVA. Worm-detection imaging algorithms for VNIR and NIR imaging exhibited prediction accuracies of 97.00% (RI547/945) and 100.0% (RI1064/1176, SI1064-1176, RSI-I(1064-1173)/1064, and RSI-II(1064-1176)/(1064+1176)), respectively. The two HSI techniques revealed that spectral images with a pixel size of 1 × 1 mm or 2 × 2 mm had the best classification accuracy for worms. The results demonstrate that hyperspectral reflectance imaging techniques have the potential to detect worms in fresh-cut lettuce. Future research relating to this work will focus on a real-time sorting system for lettuce that can simultaneously detect various defects such as browning, worms, and slugs.

  17. 3-D segmentation of articular cartilages by graph cuts using knee MR images from osteoarthritis initiative

    NASA Astrophysics Data System (ADS)

    Shim, Hackjoon; Lee, Soochan; Kim, Bohyeong; Tao, Cheng; Chang, Samuel; Yun, Il Dong; Lee, Sang Uk; Kwoh, Kent; Bae, Kyongtae

    2008-03-01

    Knee osteoarthritis is the most common debilitating health condition affecting elderly population. MR imaging of the knee is highly sensitive for diagnosis and evaluation of the extent of knee osteoarthritis. Quantitative analysis of the progression of osteoarthritis is commonly based on segmentation and measurement of articular cartilage from knee MR images. Segmentation of the knee articular cartilage, however, is extremely laborious and technically demanding, because the cartilage is of complex geometry and thin and small in size. To improve precision and efficiency of the segmentation of the cartilage, we have applied a semi-automated segmentation method that is based on an s/t graph cut algorithm. The cost function was defined integrating regional and boundary cues. While regional cues can encode any intensity distributions of two regions, "object" (cartilage) and "background" (the rest), boundary cues are based on the intensity differences between neighboring pixels. For three-dimensional (3-D) segmentation, hard constraints are also specified in 3-D way facilitating user interaction. When our proposed semi-automated method was tested on clinical patients' MR images (160 slices, 0.7 mm slice thickness), a considerable amount of segmentation time was saved with improved efficiency, compared to a manual segmentation approach.

  18. Boundary detection in medical images using edge following algorithm based on intensity gradient and texture gradient features.

    PubMed

    Somkantha, Krit; Theera-Umpon, Nipon; Auephanwiriyakul, Sansanee

    2011-03-01

    Finding the correct boundary in noisy images is still a difficult task. This paper introduces a new edge following technique for boundary detection in noisy images. Utilization of the proposed technique is exhibited via its application to various types of medical images. Our proposed technique can detect the boundaries of objects in noisy images using the information from the intensity gradient via the vector image model and the texture gradient via the edge map. The performance and robustness of the technique have been tested to segment objects in synthetic noisy images and medical images including prostates in ultrasound images, left ventricles in cardiac magnetic resonance (MR) images, aortas in cardiovascular MR images, and knee joints in computerized tomography images. We compare the proposed segmentation technique with the active contour models (ACM), geodesic active contour models, active contours without edges, gradient vector flow snake models, and ACMs based on vector field convolution, by using the skilled doctors' opinions as the ground truths. The results show that our technique performs very well and yields better performance than the classical contour models. The proposed method is robust and applicable on various kinds of noisy images without prior knowledge of noise properties.

  19. Random Walk and Graph Cut for Co-Segmentation of Lung Tumor on PET-CT Images.

    PubMed

    Ju, Wei; Xiang, Dehui; Xiang, Deihui; Zhang, Bin; Wang, Lirong; Kopriva, Ivica; Chen, Xinjian

    2015-12-01

    Accurate lung tumor delineation plays an important role in radiotherapy treatment planning. Since the lung tumor has poor boundary in positron emission tomography (PET) images and low contrast in computed tomography (CT) images, segmentation of tumor in the PET and CT images is a challenging task. In this paper, we effectively integrate the two modalities by making fully use of the superior contrast of PET images and superior spatial resolution of CT images. Random walk and graph cut method is integrated to solve the segmentation problem, in which random walk is utilized as an initialization tool to provide object seeds for graph cut segmentation on the PET and CT images. The co-segmentation problem is formulated as an energy minimization problem which is solved by max-flow/min-cut method. A graph, including two sub-graphs and a special link, is constructed, in which one sub-graph is for the PET and another is for CT, and the special link encodes a context term which penalizes the difference of the tumor segmentation on the two modalities. To fully utilize the characteristics of PET and CT images, a novel energy representation is devised. For the PET, a downhill cost and a 3D derivative cost are proposed. For the CT, a shape penalty cost is integrated into the energy function which helps to constrain the tumor region during the segmentation. We validate our algorithm on a data set which consists of 18 PET-CT images. The experimental results indicate that the proposed method is superior to the graph cut method solely using the PET or CT is more accurate compared with the random walk method, random walk co-segmentation method, and non-improved graph cut method.

  20. Cut Front Geometry Characterization in Cutting Applications of Brass with Abrasive Water Jet

    NASA Astrophysics Data System (ADS)

    Akkurt, Adnan

    2010-06-01

    Abrasive water jet (AWJ) cutting is an advanced manufacturing process for machining hard to cut materials. In this study, brass-353 samples of different thicknesses were cut by AWJ using different feed rates to identify the relationships between depth of cut (material thickness), feed rate, and deflection of cutting edge geometry. The effects of material thickness on the AWJ cut surface roughness were investigated and discussed. Deflection of cutting edge geometry in AWJ cutting process was assessed. Cutting edge geometry was characterized by analyzing the surface properties of cut samples.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. New design of a gamma camera detector with reduced edge effect for breast imaging

    NASA Astrophysics Data System (ADS)

    Yeon Hwang, Ji; Lee, Seung-Jae; Baek, Cheol-Ha; Hyun Kim, Kwang; Hyun Chung, Yong

    2011-05-01

    In recent years, there has been a growing interest in developing small gamma cameras dedicated to breast imaging. We designed a new detector with trapezoidal shape to expand the field of view (FOV) of camera without increasing its dimensions. To find optimal parameters, images of point sources at the edge area as functions of the angle and optical treatment of crystal side surface were simulated by using a DETECT2000. Our detector employs monolithic CsI(Tl) with dimensions of 48.0×48.0×6.0 mm coupled to an array of photo-sensors. Side surfaces of crystal were treated with three different surface finishes: black absorber, metal reflector and white reflector. The trapezoidal angle varied from 45° to 90° in steps of 15°. Gamma events were generated on 15 evenly spaced points with 1.0 mm spacing in the X-axis starting 1.0 mm away from the side surface. Ten thousand gamma events were simulated at each location and images were formed by calculating the Anger-logic. The results demonstrated that all the 15 points could be identified only for the crystal with trapezoidal shape having 45° angle and white reflector on the side surface. In conclusion, our new detector proved to be a reliable design to expand the FOV of small gamma camera for breast imaging.

  3. Microwave Imaging Reflectometry for the study of Edge Harmonic Oscillations on DIII-D

    NASA Astrophysics Data System (ADS)

    Ren, X.; Chen, M.; Chen, X.; Domier, C. W.; Ferraro, N. M.; Kramer, G. J.; Luhmann, N. C., Jr.; Muscatello, C. M.; Nazikian, R.; Shi, L.; Tobias, B. J.; Valeo, E.

    2015-10-01

    Quiescent H-mode (QH-mode) is an ELM free mode of operation in which edge-localized harmonic oscillations (EHOs) are believed to enhance particle transport, thereby stabilizing ELMs and preventing damage to the divertor and plasma facing components. Microwave Imaging Reflectometer (MIR) enabling direct comparison between the measured and simulated 2D images of density fluctuations near the edge can determine the 2D structure of density oscillation, which can help to explain the physics behind EHO modes. MIR data sometimes indicate a counter-propagation between dominant (n=1) and higher harmonic modes of coherent EHOs in the steep gradient regions of the pedestal. To preclude diagnostic artifacts, we have performed forward modeling that includes possible optical mis-alignments to show that offsets between transmitting and receiving antennas do not account for this feature. We have also simulated the non-linear structure of the EHO modes, which induces multiple harmonics that are properly charaterized in the synthetic diagnostic. By excluding mis-alignments of optics as well as patially eliminating non-linearity of EHO mode structure as possible explanation for the data, counter-propagation observed in MIR data, which is not corroborated by external Mirnov coil array measurements, may be due to subtleties of the eigenmode structure, such as an inversion radius consistent with a magnetic island. Similar effects are observed in analysis of internal ECE-Imaging and BES data. The identification of a non-ideal structure motivates further exploration of nonlinear models of this instability. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

  4. Detection of Foreign Bodies and Bubble Defects in Tire Radiography Images Based on Total Variation and Edge Detection

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Li, Tao; Li, Qing-Ling

    2013-08-01

    We present the analysis and decomposition of tire radiography images by combining the total variation, curvelet transform based image enhancement, and Canny edge detection to detect foreign bodies and bubble defects in tires. Relying on the feature of total variation that images can be decomposed as texture parts and cartoon parts, we decompose the tire radiography image and select the cartoon part for defect detection since the textures are segmented and defect information is retained. The edges of the image are enhanced by modifying the curvelet coefficients before further edge detection operation. Furthermore, a Canny edge detection operator is used to detect the defects in which the eight-neighborhood bilinear interpolation non-maximum suppression method is employed to improve the detection performance. In our experiments, the Sobel operator and state-of-the-art methods such as the LoG operator and Canny edge detection algorithms are employed for comparison, and the experimental results are discussed briefly. The experimental results indicate that foreign bodies and bubbles in tires can be detected and located accurately by our proposed method.

  5. Highspeed laser ablation cutting of metal

    NASA Astrophysics Data System (ADS)

    Ullmann, F.; Loeschner, U.; Hartwig, L.; Szczepanski, D.; Schille, J.; Gronau, S.; Knebel, T.; Drechsel, J.; Ebert, R.; Exner, H.

    2013-02-01

    In laser ablation cutting, irradiation of high-intense laser beams causes ejection of molten and evaporated material out of the cutting zone as a result of high pressure gradients, induced by expanding plasma plumes. This paper investigates highspeed laser ablation cutting of industrial grade metal sheets using high-brilliant continuous wave fiber lasers with output powers up to 5 kW. The laser beam was deflected with scan speeds up to 2700 m/min utilizing both a fast galvanometer scan system and a polygon scan system. By sharp laser beam focusing using different objectives with focal lengths ranging between 160 mm and 500 mm, small laser spot diameters between 16.5 μm and 60 μm were obtained, respectively. As a result high peak intensities between 3*108 W/cm² and 2.5*109 W/cm² were irradiated on the sample surface, and cutting kerfs with a maximum depth of 1.4 mm have been produced. In this study the impact of the processing parameters laser power, laser spot diameter, cutting speed, and number of scans on both the achievable cutting depth and the cutting edge quality was investigated. The ablation depths, the heights of the cutting burr, as well as the removed material volumes were evaluated by means of optical microscope images and cross section photographs. Finally highspeed laser ablation cutting was studied using an intensified ultra highspeed camera in order to get useful insights into the cutting process.

  6. Implications of image plane line-edge roughness requirements on extreme ultraviolet mask specifications

    SciTech Connect

    Naulleau, P. P.; George, Simi A.

    2009-02-13

    Line-edge roughness (LER) and the related effect of contact size variation remain as significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. LER is typically viewed as a resist problem; however, recent simulation results have shown that the mask can indeed be an important contributor. Problems arise from both mask absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam (see Fig. 1). The latter effect is especially important as higher coherence off-axis illumination conditions are used and defocus is considered. Here we describe these effect in detail and explore how they will impact EUV mask requirements for the 22-nm half-pitch node and beyond. Figure 2 shows modeling results for 22-nm lines printed in a 0.32-numerical aperture system with 100-nm defocus assuming a mask with 0.24-nm rms multilayer roughness and no absorber edge roughness (unlike the example in Fig. 1). The impact of the phase roughness on the printed line-edge roughness is clearly evident and demonstrates the basic problem with mask roughness. The more detailed modeling-based analysis to be presented will account for performance throughout the process window as well as non-stochastic resist effects. We note that the mean-field resist effect is important to consider because, in practice, the resist is the limiting resolution element in the system and therefore dominates the mask-error enhancement factor (MEEF). As is typically the case with projection-optic-induced MEEF, the resist-induced MEEF will lead to even tighter mask requirements. Note that we do not consider resist stochastic effects since the purpose of this study is isolate mask-induced sources of image-plane roughness.

  7. SU-E-I-12: Characterization of Edge Effects in a Commercial Low-Dose Image Processing System

    SciTech Connect

    Marsh, R; Silosky, M

    2014-06-01

    Purpose: Minimizing radiation dose while preserving image quality is critical in fluoroscopic imaging. One recent development is a noise reduction system (Allura Clarity) offered by Philips. Others have reported approximately 50% reduction in air kerma when using Clarity. These studies, however, provide only a cursory look at how the Clarity system affects image quality. The purpose of this work was to evaluate the effect of Clarity on the appearance of high-frequency image information. Methods: A lead attenuator with a smooth edge was imaged on two Philips Allura FD20 detectors: one with Clarity and one without. The edge was positioned in the center of the field of view and images were obtained under the following conditions: 40cm and 11cm fields of view, single shot and continuous fluoroscopy modes, and using abdomen and cardiac protocols, for a total of sixteen imaging conditions. Profiles were drawn perpendicular to the edge across 80% of its length, averaged to reduce noise, normalized to the maximum pixel value, and plotted as a function of distance. Results: For all single-shot acquisitions and most fluoroscopic images, overshoot of the edge was observed. This effect was more substantial for single-shot acquisitions (∼20%) than for fluoroscopic images (∼50%). For fluoroscopic acquisition, the overshoot decayed more quickly with the Clarity system. However, the system with Clarity introduced a ringing effect for both single-shot and fluoroscopic images that is not present on the non-Clarity system. Conclusion: Previous reports have demonstrated a substantial dose reduction when using Clarity but the impact this has on image appearance has not been characterized. One demonstrated difference is the change in appearance of high-frequency image information. It remains to be determined whether this effect may impact clinical images adversely.

  8. Fluorescence imaging of macromolecule transport in high molecular weight cut-off microdialysis.

    PubMed

    Chu, Jiangtao; Koudriavtsev, Vitali; Hjort, Klas; Dahlin, Andreas P

    2014-11-01

    When microdialysis (MD) membrane exceeds molecular weight cut-off (MWCO) of 100 kDa, the fluid mechanics are in the ultrafiltration regime. Consequently, fluidic mass transport of macromolecules in the perfusate over the membrane may reduce the biological relevance of the sampling and cause an inflammatory response in the test subject. Therefore, a method to investigate the molecular transport of high MWCO MD is presented. An in vitro test chamber was fabricated to facilitate the fluorescent imaging of the MD sampling process, using fluoresceinylisothiocyanate (FITC) dextran and fluorescence microscopy. Qualitative studies on dextran behavior inside and outside the membrane were performed. Semiquantitative results showed clear dextran leakage from both 40 and 250 kDa dextran when 100 kDa MWCO membranes were used. Dextran 40 kDa leaked out with an order of magnitude higher concentration and the leakage pattern resembled more of a convective flow pattern compared with dextran 250 kDa, where the leakage pattern was more diffusion based. No leakage was observed when dextran 500 kDa was used as a colloid osmotic agent. The results in this study suggest that fluorescence imaging could be used as a method for qualitative and semiquantitative molecular transport and fluid dynamics studies of MD membranes and other hollow fiber catheter membranes.

  9. Involving Minority High School Students in Cutting Edge Research through C-DEBI, an NSF-National Science and Technology Center

    NASA Astrophysics Data System (ADS)

    Singer, E.; Edwards, K. J.

    2012-12-01

    The Center for Dark Energy Biosphere Investigations (C-DEBI) was established as a National Science and Technology Center (NTC) funded by NSF in 2009. Its mission is to explore life beneath the seafloor and make transformative discoveries that advance science, benefit society, and inspire people of all ages and origins. Thanks to the multi-institutional character of C-DEBI, the Center has not only started a collaborative framework for experimental and exploratory research, but also targets education programs at the K-12, undergraduate, graduate and postdoctoral levels involving biogeochemists, microbiologists, geochemists and geologists. An example for this is the introduction of deep biosphere research into the K-12 classroom. In this context, C-DEBI has collaborated with teachers from the Animo Leadership High School in Inglewood, which is ranked 27th within California and has a total minority enrollment of 99%, to adapt Marine Biology classes and introduce latest Deep Biosphere Science discoveries. Three high school students participated in a pilot project over 6 months to gain hands-on experience in an ongoing study in a Marine Microbiology laboratory at University of Southern California. Graduate and postdoctoral students from the Departments of Biological and Earth Sciences supervised theory, praxis and project design, which was aimed at culturing strains of Marinobacter, one of the most ubiquitous marine microbial genera, and preparing extracted DNA for sequencing using the latest Ion Torrent Technology. Students learned about the interdisciplinary global context of the study and gained experience in laboratory procedures, including basic aseptical techniques, molecular biology methods, and cutting-edge sequencing Technology, as well as problem-solving and creative thinking in project preparation and conduction. This hands-on training included discussions about the 'Whys' and 'Hows' in today's research with respect to their specific project, but also from a

  10. The influence of edge detection algorithms on the estimation of the fractal dimension of binary digital images

    NASA Astrophysics Data System (ADS)

    Ahammer, Helmut; DeVaney, Trevor T. J.

    2004-03-01

    The boundary of a fractal object, represented in a two-dimensional space, is theoretically a line with an infinitely small width. In digital images this boundary or contour is limited to the pixel resolution of the image and the width of the line commonly depends on the edge detection algorithm used. The Minkowski dimension was evaluated by using three different edge detection algorithms (Sobel, Roberts, and Laplace operator). These three operators were investigated because they are very widely used and because their edge detection result is very distinct concerning the line width. Very common fractals (Sierpinski carpet and Koch islands) were investigated as well as the binary images from a cancer invasion assay taken with a confocal laser scanning microscope. The fractal dimension is directly proportional to the width of the contour line and the fact, that in practice very often the investigated objects are fractals only within a limited resolution range is considered too.

  11. The influence of edge detection algorithms on the estimation of the fractal dimension of binary digital images.

    PubMed

    Ahammer, Helmut; DeVaney, Trevor T J

    2004-03-01

    The boundary of a fractal object, represented in a two-dimensional space, is theoretically a line with an infinitely small width. In digital images this boundary or contour is limited to the pixel resolution of the image and the width of the line commonly depends on the edge detection algorithm used. The Minkowski dimension was evaluated by using three different edge detection algorithms (Sobel, Roberts, and Laplace operator). These three operators were investigated because they are very widely used and because their edge detection result is very distinct concerning the line width. Very common fractals (Sierpinski carpet and Koch islands) were investigated as well as the binary images from a cancer invasion assay taken with a confocal laser scanning microscope. The fractal dimension is directly proportional to the width of the contour line and the fact, that in practice very often the investigated objects are fractals only within a limited resolution range is considered too.

  12. Underwater Hyperspectral Imaging (UHI) for Assessing the Coverage of Drill Cuttings on Benthic Habitats

    NASA Astrophysics Data System (ADS)

    Erdal, I.; Sandvik Aas, L. M.; Cochrane, S.; Ekehaug, S.; Hansen, I. M.

    2016-02-01

    Larger-scale mapping of seabed areas requires improved methods in order to obtain effective and sound marine management. The state of the art for visual surveys today involves video transects, which is a proven, yet time consuming and subjective method. Underwater hyperspectral imaging (UHI) utilizes high color sensitive information in the visible light reflected from objects on the seafloor to automatically identify seabed organisms and other objects of interest (OOI). A spectral library containing optical fingerprints of a range of OOI's are used in the classification. The UHI is a push-broom hyperspectral camera utilizing a state of the art CMOS sensor ensuring high sensitivity and low noise levels. Dedicated lamps illuminate the imaging area of the seafloor. Specialized software is used both for processing raw data and for geo-localization and OOI identification. The processed hyperspectral image are used as a reference when extracting new spectral data for OOI's to the spectral library. By using the spectral library in classification algorithms, large sea floor areas can automatically be classified. Recent advantages in UHI classification includes mapping of areas affected by drill cuttings. Tools for automated classification of seabed that have a different bottom composition than adjacent baseline areas are under development. Tests have been applied to a transect in gradient from the drilling hole to baseline seabed. Some areas along the transect were identified as different compared to baseline seabed. The finding was supported by results from traditional seabed mapping methods. We propose that this can be a useful tool for tomorrows environmental mapping and monitoring of drill sites.

  13. PISA: Pixelwise Image Saliency by Aggregating Complementary Appearance Contrast Measures With Edge-Preserving Coherence

    NASA Astrophysics Data System (ADS)

    Wang, Keze; Lin, Liang; Lu, Jiangbo; Li, Chenglong; Shi, Keyang

    2015-10-01

    Driven by recent vision and graphics applications such as image segmentation and object recognition, computing pixel-accurate saliency values to uniformly highlight foreground objects becomes increasingly important. In this paper, we propose a unified framework called PISA, which stands for Pixelwise Image Saliency Aggregating various bottom-up cues and priors. It generates spatially coherent yet detail-preserving, pixel-accurate and fine-grained saliency, and overcomes the limitations of previous methods which use homogeneous superpixel-based and color only treatment. PISA aggregates multiple saliency cues in a global context such as complementary color and structure contrast measures with their spatial priors in the image domain. The saliency confidence is further jointly modeled with a neighborhood consistence constraint into an energy minimization formulation, in which each pixel will be evaluated with multiple hypothetical saliency levels. Instead of using global discrete optimization methods, we employ the cost-volume filtering technique to solve our formulation, assigning the saliency levels smoothly while preserving the edge-aware structure details. In addition, a faster version of PISA is developed using a gradient-driven image sub-sampling strategy to greatly improve the runtime efficiency while keeping comparable detection accuracy. Extensive experiments on a number of public datasets suggest that PISA convincingly outperforms other state-of-the-art approaches. In addition, with this work we also create a new dataset containing $800$ commodity images for evaluating saliency detection. The dataset and source code of PISA can be downloaded at http://vision.sysu.edu.cn/project/PISA/

  14. Refrigerated cutting tools improve machining of superalloys

    NASA Technical Reports Server (NTRS)

    Dudley, G. M.

    1971-01-01

    Freon-12 applied to tool cutting edge evaporates quickly, leaves no residue, and permits higher cutting rate than with conventional coolants. This technique increases cutting rate on Rene-41 threefold and improves finish of machined surface.

  15. K-edge imaging with the XPAD3 hybrid pixel detector, direct comparison of CdTe and Si sensors.

    PubMed

    Cassol, F; Portal, L; Graber-Bolis, J; Perez-Ponce, H; Dupont, M; Kronland, C; Boursier, Y; Blanc, N; Bompard, F; Boudet, N; Buton, C; Clémens, J C; Dawiec, A; Debarbieux, F; Delpierre, P; Hustache, S; Vigeolas, E; Morel, C

    2015-07-21

    We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images.

  16. Random walk and graph cut based active contour model for three-dimension interactive pituitary adenoma segmentation from MR images

    NASA Astrophysics Data System (ADS)

    Sun, Min; Chen, Xinjian; Zhang, Zhiqiang; Ma, Chiyuan

    2017-02-01

    Accurate volume measurements of pituitary adenoma are important to the diagnosis and treatment for this kind of sellar tumor. The pituitary adenomas have different pathological representations and various shapes. Particularly, in the case of infiltrating to surrounding soft tissues, they present similar intensities and indistinct boundary in T1-weighted (T1W) magnetic resonance (MR) images. Then the extraction of pituitary adenoma from MR images is still a challenging task. In this paper, we propose an interactive method to segment the pituitary adenoma from brain MR data, by combining graph cuts based active contour model (GCACM) and random walk algorithm. By using the GCACM method, the segmentation task is formulated as an energy minimization problem by a hybrid active contour model (ACM), and then the problem is solved by the graph cuts method. The region-based term in the hybrid ACM considers the local image intensities as described by Gaussian distributions with different means and variances, expressed as maximum a posteriori probability (MAP). Random walk is utilized as an initialization tool to provide initialized surface for GCACM. The proposed method is evaluated on the three-dimensional (3-D) T1W MR data of 23 patients and compared with the standard graph cuts method, the random walk method, the hybrid ACM method, a GCACM method which considers global mean intensity in region forces, and a competitive region-growing based GrowCut method planted in 3D Slicer. Based on the experimental results, the proposed method is superior to those methods.

  17. Prediction of foal carcass composition and wholesale cut yields by using video image analysis.

    PubMed

    Lorenzo, J M; Guedes, C M; Agregán, R; Sarriés, M V; Franco, D; Silva, S R

    2017-07-11

    This work represents the first contribution for the application of the video image analysis (VIA) technology in predicting lean meat and fat composition in the equine species. Images of left sides of the carcass (n=42) were captured from the dorsal, lateral and medial views using a high-resolution digital camera. A total of 41 measurements (angles, lengths, widths and areas) were obtained by VIA. The variation of percentage of lean meat obtained from the forequarter (FQ) and hindquarter (HQ) carcass ranged between 5.86% and 7.83%. However, the percentage of fat (FAT) obtained from the FQ and HQ carcass presented a higher variation (CV between 41.34% and 44.58%). By combining different measurements and using prediction models with cold carcass weight (CCW) and VIA measurement the coefficient of determination (k-fold-R 2) were 0.458 and 0.532 for FQ and HQ, respectively. On the other hand, employing the most comprehensive model (CCW plus all VIA measurements), the k-fold-R 2 increased from 0.494 to 0.887 and 0.513 to 0.878 with respect to the simplest model (only with CCW), while precision increased with the reduction in the root mean square error (2.958 to 0.947 and 1.841 to 0.787) for the hindquarter fat and lean percentage, respectively. With CCW plus VIA measurements is possible to explain the wholesale value cuts yield variation (k-fold-R 2 between 0.533 and 0.889). Overall, the VIA technology performed in the present study could be considered as an accurate method to assess the horse carcass composition which could have a role in breeding programmes and research studies to assist in the development of a value-based marketing system for horse carcass.

  18. K-edge digital subtraction imaging with dichromatic x-ray sources: SNR and dose studies

    NASA Astrophysics Data System (ADS)

    Sarnelli, A.; Elleaume, H.; Taibi, A.; Gambaccini, M.; Bravin, A.

    2006-09-01

    The aim of the present work is to analytically evaluate the signal to noise ratio (SNR) and the delivered dose in K-edge digital subtraction imaging (KES) using two types of x-ray sources: a monochromatic x-ray source (available at synchrotron radiation facilities and considered as gold standard) and a quasi-monochromatic compact source. The energy separation ΔE between the two monochromatic beams is 1 keV and 4 keV for the two sources, respectively. The evaluation has been performed for both radiography and computed tomography. Different geometries have been studied to mimic clinical situations. In mammography, a pathology perfused by a contrast agent has been modelled; in angiography, a vessel superimposed to a ventricle or a stand-alone artery stenosis has been studied. The SNR and the skin dose have been calculated as a function of the detail diameter, the contrast agent (iodine and gadolinium), and its concentration in the tissues. Results show that for ΔE = 4 keV a slightly higher delivered dose is required to obtain the same SNR with respect to ΔE < 1 keV. A similar study has been performed for KES-CT. Computer simulations of CT images performed with Snark software are shown to validate the analytical calculations.

  19. The Edge of Jupiter

    NASA Image and Video Library

    2017-04-19

    This enhanced color Jupiter image, taken by the JunoCam imager on NASA's Juno spacecraft, showcases several interesting features on the apparent edge (limb) of the planet. Prior to Juno's fifth flyby over Jupiter's mysterious cloud tops, members of the public voted on which targets JunoCam should image. This picture captures not only a fascinating variety of textures in Jupiter's atmosphere, it also features three specific points of interest: "String of Pearls," "Between the Pearls," and "An Interesting Band Point." Also visible is what's known as the STB Spectre, a feature in Jupiter's South Temperate Belt where multiple atmospheric conditions appear to collide. JunoCam images of Jupiter sometimes appear to have an odd shape. This is because the Juno spacecraft is so close to Jupiter that it cannot capture the entire illuminated area in one image -- the sides get cut off. Juno acquired this image on March 27, 2017, at 2:12 a.m. PDT (5:12 a.m. EDT), as the spacecraft performed a close flyby of Jupiter. When the image was taken, the spacecraft was about 12,400 miles (20,000 kilometers) from the planet. This enhanced color image was created by citizen scientist Bjorn Jonsson. https://photojournal.jpl.nasa.gov/catalog/PIA21389

  20. Image resolution enhancement using edge extraction and sparse representation in wavelet domain for real-time application

    NASA Astrophysics Data System (ADS)

    Ponomaryov, Volodymyr I.; Chavez-Roman, Herminio; Gonzalez-Huitron, Victor

    2014-05-01

    The paper presents the design and hardware implementation of novel framework for image resolution enhancement employing the wavelet domain. The principal idea of resolution enhancement consists of using edge preservation procedure and mutual interpolation between the input low-resolution (LR) image and the HF sub-band images performed via the Discrete Wavelet Transform (DWT). The LR image is used in the sparse representation for the resolutionenhancement process, employing a 1-D interpolation in set of angle directions; following, the computations of the new samples are found, estimating the missing samples. Finally, pixels are performed via the Lanczos interpolation. To preserve more edge information additional edge extraction in HF sub-bands is performed in the DWT decomposition of input image. The differences between the LL sub-band image and LR input image is used to correct the HF component, generating a significantly sharper reconstructed image. All sub-band images are used to generate the new HR image applying the inverse DWT (IDWT). Additionally, the novel framework employs a denoising procedure by using the Non-Local Means for the input LR image. An efficiency analysis of the designed and other state-of-the-art filters have been performed on the DSP TMS320DM648 by Texas Instruments through MATLAB's Simulink module and on the video card (NVIDIA®Quadro® K2000), showing that novel SR procedure can be used in real-time processing applications. Experimental results have confirmed that implemented framework outperforms existing SR algorithms in terms of objective criteria (PSNR, MAE and SSIM) as well as in subjective perception, justifying better image resolution.

  1. Edge Based 3d Indoor Corridor Modeling Using a Single Image

    NASA Astrophysics Data System (ADS)

    Baligh Jahromi, A.; Sohn, G.

    2015-08-01

    Reconstruction of spatial layout of indoor scenes from a single image is inherently an ambiguous problem. However, indoor scenes are usually comprised of orthogonal planes. The regularity of planar configuration (scene layout) is often recognizable, which provides valuable information for understanding the indoor scenes. Most of the current methods define the scene layout as a single cubic primitive. This domain-specific knowledge is often not valid in many indoors where multiple corridors are linked each other. In this paper, we aim to address this problem by hypothesizing-verifying multiple cubic primitives representing the indoor scene layout. This method utilizes middle-level perceptual organization, and relies on finding the ground-wall and ceiling-wall boundaries using detected line segments and the orthogonal vanishing points. A comprehensive interpretation of these edge relations is often hindered due to shadows and occlusions. To handle this problem, the proposed method introduces virtual rays which aid in the creation of a physically valid cubic structure by using orthogonal vanishing points. The straight line segments are extracted from the single image and the orthogonal vanishing points are estimated by employing the RANSAC approach. Many scene layout hypotheses are created through intersecting random line segments and virtual rays of vanishing points. The created hypotheses are evaluated by a geometric reasoning-based objective function to find the best fitting hypothesis to the image. The best model hypothesis offered with the highest score is then converted to a 3D model. The proposed method is fully automatic and no human intervention is necessary to obtain an approximate 3D reconstruction.

  2. Three-dimensional labeling of newly formed bone using synchrotron radiation barium K-edge subtraction imaging

    NASA Astrophysics Data System (ADS)

    Panahifar, Arash; Swanston, Treena M.; Pushie, M. Jake; Belev, George; Chapman, Dean; Weber, Lynn; Cooper, David M. L.

    2016-07-01

    Bone is a dynamic tissue which exhibits complex patterns of growth as well as continuous internal turnover (i.e. remodeling). Tracking such changes can be challenging and thus a high resolution imaging-based tracer would provide a powerful new perspective on bone tissue dynamics. This is, particularly so if such a tracer can be detected in 3D. Previously, strontium has been demonstrated to be an effective tracer which can be detected by synchrotron-based dual energy K-edge subtraction (KES) imaging in either 2D or 3D. The use of strontium is, however, limited to very small sample thicknesses due to its low K-edge energy (16.105 keV) and thus is not suitable for in vivo application. Here we establish proof-of-principle for the use of barium as an alternative tracer with a higher K-edge energy (37.441 keV), albeit for ex vivo imaging at the moment, which enables application in larger specimens and has the potential to be developed for in vivo imaging of preclinical animal models. New bone formation within growing rats in 2D and 3D was demonstrated at the Biomedical Imaging and Therapy bending magnet (BMIT-BM) beamline of the Canadian Light Source synchrotron. Comparative x-ray fluorescence imaging confirmed those patterns of uptake detected by KES. This initial work provides a platform for the further development of this tracer and its exploration of applications for in vivo development.

  3. Application of chlorophyll fluorescence imaging and hyperspectral imaging in evaluation of decay in fresh-cut lettuce

    USDA-ARS?s Scientific Manuscript database

    Lettuce (Lactuca sativa L.) is commercially the most popular leafy vegetable whose leaves are usually consumed raw. Cleaned, cored, and chopped (fresh-cut) lettuce is a desirable, but highly perishable product. Modified atmosphere packaging (MAP) has been introduced to maintain quality of fresh-cut ...

  4. Edge density imaging: mapping the anatomic embedding of the structural connectome within the white matter of the human brain.

    PubMed

    Owen, Julia P; Chang, Yi Shin; Mukherjee, Pratik

    2015-04-01

    The structural connectome has emerged as a powerful tool to characterize the network architecture of the human brain and shows great potential for generating important new biomarkers for neurologic and psychiatric disorders. The edges of the cerebral graph traverse white matter to interconnect cortical and subcortical nodes, although the anatomic embedding of these edges is generally overlooked in the literature. Mapping the paths of the connectome edges could elucidate the relative importance of individual white matter tracts to the overall network topology of the brain and also lead to a better understanding of the effect of regionally-specific white matter pathology on cognition and behavior. In this work, we introduce edge density imaging (EDI), which maps the number of network edges that pass through every white matter voxel. Test-retest analysis shows good to excellent reliability for edge density (ED) measurements, with consistent results using different cortical and subcortical parcellation schemes and different diffusion MR imaging acquisition parameters. We also demonstrate that ED yields complementary information to both traditional and emerging voxel-wise metrics of white matter microstructure and connectivity, including fractional anisotropy, track density, fiber orientation dispersion and neurite density. Our results demonstrate spatially ordered variations of ED throughout the white matter, notably including greater ED in posterior than anterior cerebral white matter. The EDI framework is employed to map the white matter regions that are enriched with pathways connecting rich club nodes and also those with high densities of intra-modular and inter-modular edges. We show that periventricular white matter has particularly high ED and high densities of rich club edges, which is significant for diseases in which these areas are selectively affected, ranging from white matter injury of prematurity in infants to leukoaraiosis in the elderly. Using edge

  5. Edge Density Imaging: Mapping the Anatomic Embedding of the Structural Connectome Within the White Matter of the Human Brain

    PubMed Central

    Owen, Julia P.; Chang, Yi-Shin; Mukherjee, Pratik

    2015-01-01

    The structural connectome has emerged as a powerful tool to characterize the network architecture of the human brain and shows great potential for generating important new biomarkers for neurologic and psychiatric disorders. The edges of the cerebral graph traverse white matter to interconnect cortical and subcortical nodes, although the anatomic embedding of these edges is generally overlooked in the literature. Mapping the paths of the connectome edges could elucidate the relative importance of individual white matter tracts to the overall network topology of the brain and also lead to a better understanding of the effect of regionally-specific white matter pathology on cognition and behavior. In this work, we introduce edge density imaging (EDI), which maps the number of network edges that pass through every white matter voxel. Test-retest analysis shows good to excellent reliability for edge density (ED) measurements, with consistent results using different cortical and subcortical parcellation schemes and different diffusion MR imaging acquisition parameters. We also demonstrate that ED yields complementary information to both traditional and emerging voxel-wise metrics of white matter microstructure and connectivity, including fractional anisotropy, track density, fiber orientation dispersion and neurite density. Our results demonstrate spatially ordered variations of ED throughout the white matter, notably including greater ED in posterior than anterior cerebral white matter. The EDI framework is employed to map the white matter regions that are enriched with pathways connecting rich club nodes and also those with high densities of intra-modular and inter-modular edges. We show that periventricular white matter has particularly high ED and high densities of rich club edges, which is significant for diseases in which these areas are selectively affected, ranging from white matter injury of prematurity in infants to leukoaraiosis in the elderly. Using edge

  6. Effects of image orientation and ground control points distribution on unmanned aerial vehicle photogrammetry projects on a road cut slope

    NASA Astrophysics Data System (ADS)

    Carvajal-Ramírez, Fernando; Agüera-Vega, Francisco; Martínez-Carricondo, Patricio J.

    2016-07-01

    The morphology of road cut slopes, such as length and high slopes, is one of the most prevalent causes of landslides and terrain stability troubles. Digital elevation models (DEMs) and orthoimages are used for land management purposes. Two flights with different orientations with respect to the target surface were planned, and four photogrammetric projects were carried out during these flights to study the image orientation effects. Orthogonal images oriented to the cut slope with only sidelaps were compared to the classical vertical orientation, with sidelapping, endlapping, and both types of overlapping simultaneously. DEM and orthoimages obtained from the orthogonal project showed smaller errors than those obtained from the other three photogrammetric projects, with the first one being much easier to manage. One additional flight and six photogrammetric projects were used to establish an objective criterion to locate the three ground control points for georeferencing and rectification DEMs and orthoimages. All possible sources of errors were evaluated in the DEMs and orthoimages.

  7. RIXS, XEOL and XEOL Imaging of Rare-earth Phosphors at the L3,2-edges

    SciTech Connect

    Sham, T.K.; Gordon, R.A.

    2010-07-19

    Capabilities at the PNC-XOR of the Advanced Photon Source to monitor Resonant Inelastic X-ray Scattering (RIXS) in the intermediate X-ray energy range using a wavelength dispersive spectrometer (WDX) and associated X-ray Excited Optical Luminescence (XEOL) using an optical spectrometer will be described. Ce L3 -edge of Ce and Tb doped inorganic phosphors have been investigated using these techniques and corresponding X-ray Absorption Near-Edge Structures (XANES) using a micro X-ray beam with X-ray fluorescence and optical luminescence yield. Results from these studies and their prospects for future applications in XEOL imaging will be discussed.

  8. Toroidal mode number estimation of the edge-localized modes using the KSTAR 3-D electron cyclotron emission imaging system

    SciTech Connect

    Lee, J.; Yun, G. S. Lee, J. E.; Kim, M.; Choi, M. J.; Lee, W.; Park, H. K.; Domier, C. W.; Luhmann, N. C.; Sabbagh, S. A.; Park, Y. S.; Lee, S. G.; Bak, J. G.

    2014-06-15

    A new and more accurate technique is presented for determining the toroidal mode number n of edge-localized modes (ELMs) using two independent electron cyclotron emission imaging (ECEI) systems in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The technique involves the measurement of the poloidal spacing between adjacent ELM filaments, and of the pitch angle α{sub *} of filaments at the plasma outboard midplane. Equilibrium reconstruction verifies that α{sub *} is nearly constant and thus well-defined at the midplane edge. Estimates of n obtained using two ECEI systems agree well with n measured by the conventional technique employing an array of Mirnov coils.

  9. Toroidal mode number estimation of the edge-localized modes using the KSTAR 3-D electron cyclotron emission imaging system

    NASA Astrophysics Data System (ADS)

    Lee, J.; Yun, G. S.; Lee, J. E.; Kim, M.; Choi, M. J.; Lee, W.; Park, H. K.; Domier, C. W.; Luhmann, N. C.; Sabbagh, S. A.; Park, Y. S.; Lee, S. G.; Bak, J. G.

    2014-06-01

    A new and more accurate technique is presented for determining the toroidal mode number n of edge-localized modes (ELMs) using two independent electron cyclotron emission imaging (ECEI) systems in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The technique involves the measurement of the poloidal spacing between adjacent ELM filaments, and of the pitch angle α* of filaments at the plasma outboard midplane. Equilibrium reconstruction verifies that α* is nearly constant and thus well-defined at the midplane edge. Estimates of n obtained using two ECEI systems agree well with n measured by the conventional technique employing an array of Mirnov coils.

  10. Toroidal mode number estimation of the edge-localized modes using the KSTAR 3-D electron cyclotron emission imaging system.

    PubMed

    Lee, J; Yun, G S; Lee, J E; Kim, M; Choi, M J; Lee, W; Park, H K; Domier, C W; Luhmann, N C; Sabbagh, S A; Park, Y S; Lee, S G; Bak, J G

    2014-06-01

    A new and more accurate technique is presented for determining the toroidal mode number n of edge-localized modes (ELMs) using two independent electron cyclotron emission imaging (ECEI) systems in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. The technique involves the measurement of the poloidal spacing between adjacent ELM filaments, and of the pitch angle α* of filaments at the plasma outboard midplane. Equilibrium reconstruction verifies that α* is nearly constant and thus well-defined at the midplane edge. Estimates of n obtained using two ECEI systems agree well with n measured by the conventional technique employing an array of Mirnov coils.

  11. Quantitative Analysis Of Sperm Motion Kinematics From Real-Time Video-Edge Images

    NASA Astrophysics Data System (ADS)

    Davis, Russell O...; Katz, David F.

    1988-02-01

    A new model of sperm swimming kinematics, which uses signal processing methods and multivariate statistical techniques to identify individual cell-motion parameters and unique cell populations, is presented. Swimming paths of individual cells are obtained using real-time, video-edge digitization. Raw paths are adaptively filtered to identify average paths, and measurements of space-time oscillations about average paths are made. Time-dependent frequency information is extracted from spatial variations about average paths using harmonic analysis. Raw-path and average-path measures such as curvature, curve length, and straight-line length, and measures of oscillations about average paths such as time-dependent amplitude and frequency variations, are used in a multivariate, cluster analysis to identify unique cell populations. The entire process, including digitization of sperm video images, is computer-automated. Preliminary results indicate that this method of tracking, digitization, and kinematic analysis accurately identifies unique cell subpopulations, including: the relative numbers of cells in each subpopulation, how subpopulations differ, and the extent and significance of such differences. With appropriate work, this approach may be useful for clinical discrimination between normal and abnormal semen specimens.

  12. Enhanced patterns of oriented edge magnitudes for face recognition and image matching.

    PubMed

    Vu, Ngoc-Son; Caplier, Alice

    2012-03-01

    A good feature descriptor is desired to be discriminative, robust, and computationally inexpensive in both terms of time and storage requirement. In the domain of face recognition, these properties allow the system to quickly deliver high recognition results to the end user. Motivated by the recent feature descriptor called Patterns of Oriented Edge Magnitudes (POEM), which balances the three concerns, this paper aims at enhancing its performance with respect to all these criteria. To this end, we first optimize the parameters of POEM and then apply the whitened principal-component-analysis dimensionality reduction technique to get a more compact, robust, and discriminative descriptor. For face recognition, the efficiency of our algorithm is proved by strong results obtained on both constrained (Face Recognition Technology, FERET) and unconstrained (Labeled Faces in the Wild, LFW) data sets in addition with the low complexity. Impressively, our algorithm is about 30 times faster than those based on Gabor filters. Furthermore, by proposing an additional technique that makes our descriptor robust to rotation, we validate its efficiency for the task of image matching.

  13. TIME VARIABILITY IN THE OUTER EDGE OF SATURN'S A-RING REVEALED BY CASSINI IMAGING

    SciTech Connect

    Spitale, J. N.; Porco, C. C.

    2009-11-15

    We examine the outer edge of Saturn's A-ring, whose shape is strongly influenced by the co-orbital satellites Janus and Epimetheus, during the period from day 2005-121 to day 2009-036. Twenty-four Cassini imaging data sets are used, each one giving a picture of the ring during a short interval, allowing us to explore its time variability in detail for the first time. We find that the ring experienced a period of adjustment within {approx}8 months of the 2006 January co-orbital swap, corresponding to the interval during which the two satellites were within about 60 deg. of one another. Outside that adjustment period, the ring is dominated by an m = 7 pattern, as expected near a 7:6 inner Lindblad resonance, but the alignment is opposite in phase to that predicted for isolated test particles, and the amplitude of the radial distortion varies with time. We find that the amplitude variation corresponds to a beat pattern between the perturbations from the two satellites as would be expected if the responses add linearly. However, we also find deviations of limited azimuthal extent from the simple m = 7 pattern. Some of the additional structure may arise from coupling between the two excited modes in the ring, but the origin of these features is still under investigation.

  14. A robust active contour edge detection algorithm based on local Gaussian statistical model for oil slick remote sensing image

    NASA Astrophysics Data System (ADS)

    Jing, Yu; Wang, Yaxuan; Liu, Jianxin; Liu, Zhaoxia

    2015-08-01

    Edge detection is a crucial method for the location and quantity estimation of oil slick when oil spills on the sea. In this paper, we present a robust active contour edge detection algorithm for oil spill remote sensing images. In the proposed algorithm, we define a local Gaussian data fitting energy term with spatially varying means and variances, and this data fitting energy term is introduced into a global minimization active contour (GMAC) framework. The energy function minimization is achieved fast by a dual formulation of the weighted total variation norm. The proposed algorithm avoids the existence of local minima, does not require the definition of initial contour, and is robust to weak boundaries, high noise and severe intensity inhomogeneity exiting in oil slick remote sensing images. Furthermore, the edge detection of oil slick and the correction of intensity inhomogeneity are simultaneously achieved via the proposed algorithm. The experiment results have shown that a superior performance of proposed algorithm over state-of-the-art edge detection algorithms. In addition, the proposed algorithm can also deal with the special images with the object and background of the same intensity means but different variances.

  15. EdgeDetectPFI: An algorithm for automatic edge detection in potential field anomaly images - application to dike-like magnetic structures

    NASA Astrophysics Data System (ADS)

    Oliveira, Saulo P.; Ferreira, Francisco J. F.; Souza, Jeferson de

    2017-06-01

    We propose an algorithm to automatically locate the spatial position of anomalies in potential field images, which can be used to estimate the depth and width of causative sources. The magnetic anomaly is firstly enhanced using an edge detection filter based on a simple transformation (the Signum transform) which retains only the signs of the anomalous field. The theoretical edge positions can be recognized from the locations where one of the spatial field derivatives (or a function of them) change its sign: the zero crossover points. These points are easily identified from the Signum transformed spatial derivatives. The actual sources depths and widths are then estimated using the widths of the positive plateaus obtained from two different Signum transformed data: one based on the vertical derivative and the other using the vertical derivative minus the absolute value of the horizontal derivative. Our algorithm finds these widths in an automatic fashion by computing the radius of the largest circles inside the positive plateaus. Numerical experiments with synthetic data show that the proposed approach provides reliable estimates for the target parameters. Additional testing is carried out with aeromagnetic data from Santa Catarina, Southern Brazil, and the resulting parameter maps are compared with Euler deconvolution.

  16. Imaging at an x-ray absorption edge using free electron laser pulses for interface dynamics in high energy density systems [Resonant phase contrast imaging for interface physics

    DOE PAGES

    Beckwith, M. A.; Jiang, S.; Schropp, A.; ...

    2017-05-01

    Tuning the energy of an x-ray probe to an absorption line or edge can provide material-specific measurements that are particularly useful for interfaces. Simulated hard x-ray images above the Fe K-edge are presented to examine ion diffusion across an interface between Fe2O3 and SiO2 aerogel foam materials. The simulations demonstrate the feasibility of such a technique for measurements of density scale lengths near the interface with submicron spatial resolution. A proof-of-principle experiment is designed and performed at the Linac coherent light source facility. Preliminary data show the change of the interface after shock compression and heating with simultaneous fluorescence spectramore » for temperature determination. Here, the results provide the first demonstration of using x-ray imaging at an absorption edge as a diagnostic to detect ultrafast phenomena for interface physics in high-energy-density systems.« less

  17. A unifying graph-cut image segmentation framework: algorithms it encompasses and equivalences among them

    NASA Astrophysics Data System (ADS)

    Ciesielski, Krzysztof Chris; Udupa, Jayaram K.; Falcão, A. X.; Miranda, P. A. V.

    2012-02-01

    We present a general graph-cut segmentation framework GGC, in which the delineated objects returned by the algorithms optimize the energy functions associated with the lp norm, 1 <= p <= ∞. Two classes of well known algorithms belong to GGC: the standard graph cut GC (such as the min-cut/max-flow algorithm) and the relative fuzzy connectedness algorithms RFC (including iterative RFC, IRFC). The norm-based description of GGC provides more elegant and mathematically better recognized framework of our earlier results from [18, 19]. Moreover, it allows precise theoretical comparison of GGC representable algorithms with the algorithms discussed in a recent paper [22] (min-cut/max-flow graph cut, random walker, shortest path/geodesic, Voronoi diagram, power watershed/shortest path forest), which optimize, via lp norms, the intermediate segmentation step, the labeling of scene voxels, but for which the final object need not optimize the used lp energy function. Actually, the comparison of the GGC representable algorithms with that encompassed in the framework described in [22] constitutes the main contribution of this work.

  18. Near-infrared cut-off filters based on CMOS nanostructures for ambient light sensors and image sensors

    NASA Astrophysics Data System (ADS)

    Junger, Stephan; Verwaal, Nanko; Tschekalinskij, Wladimir; Weber, Norbert

    2014-02-01

    Silicon based photodiodes provide spectral response in the visible wavelength range (VIS) but also in the near-infrared (NIR). For ambient light sensors (ALS) and image sensors with high color reproducibility the sensitivity in the NIR is unwanted as it impairs the sensing performance. Typically, external thin film filters are applied as near-infrared cut-off filters added to the photodiode or image sensor. We demonstrate plasmonic nanostructures fabricated directly within an extended CMOS (complementary metal-oxide-semiconductor) process. Designs in one and two metal layers are used and enable ambient light sensors as well as image sensors with pixel level NIR-blocking filters for color vision and additional NIR-sensitive pixels for simultaneous acquisition of VIS and NIR images.

  19. Segmentation of prostate from ultrasound images using level sets on active band and intensity variation across edges.

    PubMed

    Li, Xu; Li, Chunming; Fedorov, Andriy; Kapur, Tina; Yang, Xiaoping

    2016-06-01

    In this paper, the authors propose a novel efficient method to segment ultrasound images of the prostate with weak boundaries. Segmentation of the prostate from ultrasound images with weak boundaries widely exists in clinical applications. One of the most typical examples is the diagnosis and treatment of prostate cancer. Accurate segmentation of the prostate boundaries from ultrasound images plays an important role in many prostate-related applications such as the accurate placement of the biopsy needles, the assignment of the appropriate therapy in cancer treatment, and the measurement of the prostate volume. Ultrasound images of the prostate are usually corrupted with intensity inhomogeneities, weak boundaries, and unwanted edges, which make the segmentation of the prostate an inherently difficult task. Regarding to these difficulties, the authors introduce an active band term and an edge descriptor term in the modified level set energy functional. The active band term is to deal with intensity inhomogeneities and the edge descriptor term is to capture the weak boundaries or to rule out unwanted boundaries. The level set function of the proposed model is updated in a band region around the zero level set which the authors call it an active band. The active band restricts the authors' method to utilize the local image information in a banded region around the prostate contour. Compared to traditional level set methods, the average intensities inside∖outside the zero level set are only computed in this banded region. Thus, only pixels in the active band have influence on the evolution of the level set. For weak boundaries, they are hard to be distinguished by human eyes, but in local patches in the band region around prostate boundaries, they are easier to be detected. The authors incorporate an edge descriptor to calculate the total intensity variation in a local patch paralleled to the normal direction of the zero level set, which can detect weak boundaries

  20. Absorption edge subtraction imaging for volumetric measurement in an animal model of malignant brain tumor

    NASA Astrophysics Data System (ADS)

    Rigley, S.; Rigon, L.; Ataelmannan, K.; Chapman, D.; Doucette, R.; Griebel, R.; Juurlink, B.; Arfelli, F.; Menk, R.-H.; Tromba, G.; Barroso, R. C.; Beveridge, T.; Lewis, R.; Pavlov, K.; Siu, K.; Hall, C.; Schültke, E.

    2005-08-01

    The goal of this project is to determine the feasibility of utilizing colloidal gold as a marker for C6 glioblastoma cells implanted into rat brain as an appropriate model for volumetric measurements of tumors using absorption edge subtraction (AES). Phase sensitive X-ray imaging is combined with KES to give good soft tissue contrast. Current methods for volumetric measurements of implanted C6 glioblastoma tumors in rat brains using MRI technology are inadequate due to the small size of the tumor (2.5-4 mm in diameter) and the thickness of the MRI slice (1-1.5 mm). Previously, our group has shown that AES detection of colloidal gold labeled C6 glioblastoma cells implanted into a rat brains may be feasible. The long-term goal for this project is to establish a method, which would allow the researcher to monitor the development of a tumor over time. Most importantly, this technique should allow researchers to accurately determine the potency of a treatment on the size and growth rate for a C6 implanted tumors. In addition, we plan to challenge the hypothesis that tumors of the glioma type do not metastasize outside of the brain. A sensitive technique for the detection of C6 cells, such as that using colloidal gold and AES/DEI, should enable researchers to detect C6 cells, which have metastasized and migrated to different areas of the body. The ability to detect implanted C6 cells followed by the development of the tumor, the possible migration of the cells and the ability to accurately measure the effects of treatments on the volume of the tumor would be of the utmost importance to brain tumor research.

  1. Geophysical imaging of metacratonizaton in the northern edge of the Congo craton in Cameroon

    NASA Astrophysics Data System (ADS)

    Goussi Ngalamo, Jeannot F.; Bisso, D.; Abdelsalam, Mohamed G.; Atekwana, Estella A.; Katumwehe, Andrew B.; Ekodeck, G. E.

    2017-05-01

    We used the World Gravity Map (WGM 2012) data to investigate the Archean Congo craton and the Oubanguides orogenic belt in Cameroon. The Oubanguides orogenic belt constitutes, from northwest to southeast, the Neoproterozoic West Cameroon domain, the Paleoproterozoic-Neoproterozoic Adamawa-Yade domain, and the dominantly Neoproterozoic Yaoundé domain (the crustal expression of the suture zone between the Congo craton and the orogenic terranes). We analyzed the WGM 2012 data to identify different gravity anomalies. We also applied the two-dimensional (2D) radially-averaged power spectral analysis to the WGM 2012 data to estimate the Moho depth. Additionally, we developed a 2D forward gravity model along a Nsbnd S profile to image the lithospheric structure of the Precambrian entities. We found that: (1) the Congo craton, the Yaoundé domain, the southeastern part of the West Cameroon domain, and the northern part of the Adamawa-Yade domain are characterized by low gravity anomaly. (2) the southern part of the Adamawa-Yade domain is marked by a pronounced E-W trending high gravity anomaly. (3) the crust is thicker beneath the Congo craton, the Yaoundé domain and the southern part of the Adamawa-Yade domain. (4) the presence of a denser lower crust material beneath the southern part of the Adamawa-Yade domain. We propose that this denser crustal material is an under-thrusted portion of the Congo craton that has been densified through metacratonization processes that accompanied collision between the craton and the orogenic terranes. This is in good agreement with geological and geochemical observations indicating that the northern edge of the Congo craton and the Adamawa-Yade domain had undergone metacratonization during the Neoproterozoic. Our suggestion is also in good agreement with observations which show that the margins of many cratons worldwide have been decratonized due to subduction processes. Our work highlights the importance of potential field geophysical

  2. Experimental feasibility of multi-energy photon-counting K-edge imaging in pre-clinical computed tomography

    NASA Astrophysics Data System (ADS)

    Schlomka, J. P.; Roessl, E.; Dorscheid, R.; Dill, S.; Martens, G.; Istel, T.; Bäumer, C.; Herrmann, C.; Steadman, R.; Zeitler, G.; Livne, A.; Proksa, R.

    2008-08-01

    Theoretical considerations predicted the feasibility of K-edge x-ray computed tomography (CT) imaging using energy discriminating detectors with more than two energy bins. This technique enables material-specific imaging in CT, which in combination with high-Z element based contrast agents, opens up possibilities for new medical applications. In this paper, we present a CT system with energy detection capabilities, which was used to demonstrate the feasibility of quantitative K-edge CT imaging experimentally. A phantom was imaged containing PMMA, calcium-hydroxyapatite, water and two contrast agents based on iodine and gadolinium, respectively. Separate images of the attenuation by photoelectric absorption and Compton scattering were reconstructed from energy-resolved projection data using maximum-likelihood basis-component decomposition. The data analysis further enabled the display of images of the individual contrast agents and their concentrations, separated from the anatomical background. Measured concentrations of iodine and gadolinium were in good agreement with the actual concentrations. Prior to the tomographic measurements, the detector response functions for monochromatic illumination using synchrotron radiation were determined in the energy range 25 keV-60 keV. These data were used to calibrate the detector and derive a phenomenological model for the detector response and the energy bin sensitivities.

  3. Automated tru-cut imaging-guided core needle biopsy of canine orbital neoplasia. A prospective feasibility study

    PubMed Central

    Cirla, A.; Rondena, M.; Bertolini, G.

    2016-01-01

    The purpose of this study was to evaluate the diagnostic value of imaging-guided core needle biopsy for canine orbital mass diagnosis. A second excisional biopsy obtained during surgery or necropsy was used as the reference standard. A prospective feasibility study was conducted in 23 canine orbital masses at a single centre. A complete ophthalmic examination was always followed by orbital ultrasound and computed tomography (CT) examination of the head. All masses were sampled with the patient still on the CT table using ultrasound (US) guided automatic tru-cut device. The most suitable sampling approach to the orbit was chosen each time based on the CT image analysis. One of the following different approaches was used: trans-orbital, trans-conjunctival or trans-masseteric. In all cases, the imaging-guided biopsy provided a sufficient amount of tissue for the histopathological diagnosis, which concurred with the biopsies obtained using the excisional technique. CT examination was essential for morphological diagnosis and provided detailed topographic information that allowed us to choose the safest orbital approach for the biopsy. US guided automatic tru-cut biopsy based on CT images, performed with patient still on the CT table, resulted in a minimally invasive, relatively easy, and accurate diagnostic procedure in dogs with orbital masses. PMID:27540512

  4. Automated tru-cut imaging-guided core needle biopsy of canine orbital neoplasia. A prospective feasibility study.

    PubMed

    Cirla, A; Rondena, M; Bertolini, G

    2016-01-01

    The purpose of this study was to evaluate the diagnostic value of imaging-guided core needle biopsy for canine orbital mass diagnosis. A second excisional biopsy obtained during surgery or necropsy was used as the reference standard. A prospective feasibility study was conducted in 23 canine orbital masses at a single centre. A complete ophthalmic examination was always followed by orbital ultrasound and computed tomography (CT) examination of the head. All masses were sampled with the patient still on the CT table using ultrasound (US) guided automatic tru-cut device. The most suitable sampling approach to the orbit was chosen each time based on the CT image analysis. One of the following different approaches was used: trans-orbital, trans-conjunctival or trans-masseteric. In all cases, the imaging-guided biopsy provided a sufficient amount of tissue for the histopathological diagnosis, which concurred with the biopsies obtained using the excisional technique. CT examination was essential for morphological diagnosis and provided detailed topographic information that allowed us to choose the safest orbital approach for the biopsy. US guided automatic tru-cut biopsy based on CT images, performed with patient still on the CT table, resulted in a minimally invasive, relatively easy, and accurate diagnostic procedure in dogs with orbital masses.

  5. Ultra-High-Speed Observation of Cutting of Failure Phenomenon in Thin Metallic Lamina by Punch and Measurement of Displacements by Digital Image Correlation Method

    NASA Astrophysics Data System (ADS)

    Nishioka, Toshihisa; Iwawaki, Takashi; Fujimoto, Takehiro; Kashiwara, Yoshiyuki

    Machine components of industrial products are often produced by press cutting. However, the mechanism of cutting (ductile fracture of metals) is not perfectly understood. In order to clarify this mechanism, cutting processes were observed by an ultrahigh-speed camera. The ultrahigh-speed camera is capable of recording maximum record rate 1,000,000 frames per second (preserved images102 frames); each frame has 80,000 pixels. Therefore, this ultrahigh-speed camera is currently the world's most advanced camera in terms of spatial and time resolutions. A detailed movie of the cutting process was recorded. The details of the cutting process include the crack length versus time, crack tip opening angle, and fracture path. The crack tip opening angles were evaluated approximately 0.1 mm behind the tip of the propagating crack. The CTOA criterion was found to be almost valid during the cutting process. Furthermore, in order to use the image correlation method, random patterns were generated by spraying paint onto the metal sections. Images of a specimen section were taken after punching the sheet metal. The distributions of displacements were evaluated by the digital image correlation method. We found smoothly cut sections and rough surfaces. A smoothly cut section is very important for industrial products. In this study, the optimal speed of punching and punch-die clearances were examined. The ductile fracture criterion determined in this study is extremely useful for fabricating machine components by press cutting because it can be used for simulations without the need for a cutting system. The data of the image correlation method can be used for an intelligent hybrid method that can provide very accurate strain and stress distributions and fracture parameters such as the T* integral, which is the most promising fracture parameter for assessing the quality of metallic materials.

  6. Randomized SUSAN edge detector

    NASA Astrophysics Data System (ADS)

    Qu, Zhi-Guo; Wang, Ping; Gao, Ying-Hui; Wang, Peng

    2011-11-01

    A speed up technique for the SUSAN edge detector based on random sampling is proposed. Instead of sliding the mask pixel by pixel on an image as the SUSAN edge detector does, the proposed scheme places the mask randomly on pixels to find edges in the image; we hereby name it randomized SUSAN edge detector (R-SUSAN). Specifically, the R-SUSAN edge detector adopts three approaches in the framework of random sampling to accelerate a SUSAN edge detector: procedure integration of response computation and nonmaxima suppression, reduction of unnecessary processing for obvious nonedge pixels, and early termination. Experimental results demonstrate the effectiveness of the proposed method.

  7. Evaluating the impact of red-edge band from Rapideye image for classifying insect defoliation levels

    NASA Astrophysics Data System (ADS)

    Adelabu, Samuel; Mutanga, Onisimo; Adam, Elhadi

    2014-09-01

    The prospect of regular assessments of insect defoliation using remote sensing technologies has increased in recent years through advances in the understanding of the spectral reflectance properties of vegetation. The aim of the present study was to evaluate the ability of the red edge channel of Rapideye imagery to discriminate different levels of insect defoliation in an African savanna by comparing the results of obtained from two classifiers. Random Forest and Support vector machine classification algorithms were applied using different sets of spectral analysis involving the red edge band. Results show that the integration of information from red edge increases classification accuracy of insect defoliation levels in all analysis performed in the study. For instance, when all the 5 bands of Rapideye imagery were used for classification, the overall accuracies increases about 19% and 21% for SVM and RF, respectively, as opposed to when the red edge channel was excluded. We also found out that the normalized difference red-edge index yielded a better accuracy result than normalized difference vegetation index. We conclude that the red-edge channel of relatively affordable and readily available high-resolution multispectral satellite data such as Rapideye has the potential to considerably improve insect defoliation classification especially in sub-Saharan Africa where data availability is limited.

  8. High-Throughput Method for Automated Colony and Cell Counting by Digital Image Analysis Based on Edge Detection.

    PubMed

    Choudhry, Priya

    2016-01-01

    Counting cells and colonies is an integral part of high-throughput screens and quantitative cellular assays. Due to its subjective and time-intensive nature, manual counting has hindered the adoption of cellular assays such as tumor spheroid formation in high-throughput screens. The objective of this study was to develop an automated method for quick and reliable counting of cells and colonies from digital images. For this purpose, I developed an ImageJ macro Cell Colony Edge and a CellProfiler Pipeline Cell Colony Counting, and compared them to other open-source digital methods and manual counts. The ImageJ macro Cell Colony Edge is valuable in counting cells and colonies, and measuring their area, volume, morphology, and intensity. In this study, I demonstrate that Cell Colony Edge is superior to other open-source methods, in speed, accuracy and applicability to diverse cellular assays. It can fulfill the need to automate colony/cell counting in high-throughput screens, colony forming assays, and cellular assays.

  9. High-Throughput Method for Automated Colony and Cell Counting by Digital Image Analysis Based on Edge Detection

    PubMed Central

    Choudhry, Priya

    2016-01-01

    Counting cells and colonies is an integral part of high-throughput screens and quantitative cellular assays. Due to its subjective and time-intensive nature, manual counting has hindered the adoption of cellular assays such as tumor spheroid formation in high-throughput screens. The objective of this study was to develop an automated method for quick and reliable counting of cells and colonies from digital images. For this purpose, I developed an ImageJ macro Cell Colony Edge and a CellProfiler Pipeline Cell Colony Counting, and compared them to other open-source digital methods and manual counts. The ImageJ macro Cell Colony Edge is valuable in counting cells and colonies, and measuring their area, volume, morphology, and intensity. In this study, I demonstrate that Cell Colony Edge is superior to other open-source methods, in speed, accuracy and applicability to diverse cellular assays. It can fulfill the need to automate colony/cell counting in high-throughput screens, colony forming assays, and cellular assays. PMID:26848849

  10. Knife-edge scanning microscopy for in silico study of cerebral blood flow: From biological imaging data to flow simulations.

    PubMed

    Nowak, Michael R; Lozovskiy, Alexander; Dobroskok, Dimitri; Yoonsuck Choe

    2016-08-01

    Knife-edge scanning microscopy provides the capability to image whole-brain cerebral microvasculature of small organisms, such as mice, at sub-micron resolution, providing a feasible foundation for the reconstruction of circulatory pathways from the systemic to cellular scale. In this paper, we illustrate the feasibility of using this data to model cerebral blood flow using numerical simulations. Starting with a small vascular element in microcirculation of interest, we present its segmentation from the imaging-data volume, construction of its triangular surface mesh, assembly of its tetrahedral volumetric mesh from the surface, and then conclude with Stokes flow simulation of plasma through the microvascular vessel.

  11. Iterative image reconstruction for cerebral perfusion CT using a pre-contrast scan induced edge-preserving prior

    NASA Astrophysics Data System (ADS)

    Ma, Jianhua; Zhang, Hua; Gao, Yang; Huang, Jing; Liang, Zhengrong; Feng, Qianjing; Chen, Wufan

    2012-11-01

    Cerebral perfusion x-ray computed tomography (PCT) imaging, which detects and characterizes the ischemic penumbra, and assesses blood-brain barrier permeability with acute stroke or chronic cerebrovascular diseases, has been developed extensively over the past decades. However, due to its sequential scan protocol, the associated radiation dose has raised significant concerns to patients. Therefore, in this study we developed an iterative image reconstruction algorithm based on the maximum a posterior (MAP) principle to yield a clinically acceptable cerebral PCT image with lower milliampere-seconds (mA s). To preserve the edges of the reconstructed image, an edge-preserving prior was designed using a normal-dose pre-contrast unenhanced scan. For simplicity, the present algorithm was termed as ‘MAP-ndiNLM’. Evaluations with the digital phantom and the simulated low-dose clinical brain PCT datasets clearly demonstrate that the MAP-ndiNLM method can achieve more significant gains than the existing FBP and MAP-Huber algorithms with better image noise reduction, low-contrast object detection and resolution preservation. More importantly, the MAP-ndiNLM method can yield more accurate kinetic enhanced details and diagnostic hemodynamic parameter maps than the MAP-Huber method.

  12. Localization and segmentation of optic disc in retinal images using circular Hough transform and grow-cut algorithm.

    PubMed

    Abdullah, Muhammad; Fraz, Muhammad Moazam; Barman, Sarah A

    2016-01-01

    Automated retinal image analysis has been emerging as an important diagnostic tool for early detection of eye-related diseases such as glaucoma and diabetic retinopathy. In this paper, we have presented a robust methodology for optic disc detection and boundary segmentation, which can be seen as the preliminary step in the development of a computer-assisted diagnostic system for glaucoma in retinal images. The proposed method is based on morphological operations, the circular Hough transform and the grow-cut algorithm. The morphological operators are used to enhance the optic disc and remove the retinal vasculature and other pathologies. The optic disc center is approximated using the circular Hough transform, and the grow-cut algorithm is employed to precisely segment the optic disc boundary. The method is quantitatively evaluated on five publicly available retinal image databases DRIVE, DIARETDB1, CHASE_DB1, DRIONS-DB, Messidor and one local Shifa Hospital Database. The method achieves an optic disc detection success rate of 100% for these databases with the exception of 99.09% and 99.25% for the DRIONS-DB, Messidor, and ONHSD databases, respectively. The optic disc boundary detection achieved an average spatial overlap of 78.6%, 85.12%, 83.23%, 85.1%, 87.93%, 80.1%, and 86.1%, respectively, for these databases. This unique method has shown significant improvement over existing methods in terms of detection and boundary extraction of the optic disc.

  13. Localization and segmentation of optic disc in retinal images using circular Hough transform and grow-cut algorithm

    PubMed Central

    Abdullah, Muhammad; Barman, Sarah A.

    2016-01-01

    Automated retinal image analysis has been emerging as an important diagnostic tool for early detection of eye-related diseases such as glaucoma and diabetic retinopathy. In this paper, we have presented a robust methodology for optic disc detection and boundary segmentation, which can be seen as the preliminary step in the development of a computer-assisted diagnostic system for glaucoma in retinal images. The proposed method is based on morphological operations, the circular Hough transform and the grow-cut algorithm. The morphological operators are used to enhance the optic disc and remove the retinal vasculature and other pathologies. The optic disc center is approximated using the circular Hough transform, and the grow-cut algorithm is employed to precisely segment the optic disc boundary. The method is quantitatively evaluated on five publicly available retinal image databases DRIVE, DIARETDB1, CHASE_DB1, DRIONS-DB, Messidor and one local Shifa Hospital Database. The method achieves an optic disc detection success rate of 100% for these databases with the exception of 99.09% and 99.25% for the DRIONS-DB, Messidor, and ONHSD databases, respectively. The optic disc boundary detection achieved an average spatial overlap of 78.6%, 85.12%, 83.23%, 85.1%, 87.93%, 80.1%, and 86.1%, respectively, for these databases. This unique method has shown significant improvement over existing methods in terms of detection and boundary extraction of the optic disc. PMID:27190713

  14. The aerodynamics of Manduca sexta: digital particle image velocimetry analysis of the leading-edge vortex.

    PubMed

    Bomphrey, Richard J; Lawson, Nicholas J; Harding, Nicholas J; Taylor, Graham K; Thomas, Adrian L R

    2005-03-01

    Here we present the first digital particle image velocimetry (DPIV) analysis of the flow field around the wings of an insect (the tobacco hawkmoth Manduca sexta, tethered to a 6-component force-moment balance in a wind tunnel). A leading-edge vortex (LEV) is present above the wings towards the end of the downstroke, as the net upward force peaks. Our DPIV analyses and smoke visualisations match the results of previous flow visualisation experiments at midwing, and we extend the experiments to provide the first analysis of the flow field above the thorax. Detailed DPIV measurements show that towards the end of the downstroke, the LEV structure is consistent with that recently reported in free-flying butterflies and dragonflies: the LEV is continuous across the thorax and runs along each wing to the wingtip, where it inflects to form the wingtip trailing vortices. The LEV core is 2-3 mm in diameter (approximately 10% of local wing chord) both at the midwing position and over the centreline at 1.2 m s(-1) and at 3.5 m s(-1) flight speeds. At 1.2 m s(-1) the measured LEV circulation is 0.012+/-0.001 m(2) s(-1) (mean +/-S.D.) at the centreline and 0.011+/-0.001 m(2) s(-1) halfway along the wing. At 3.5 m s(-1) LEV circulation is 0.011+/-0.001 m(2) s(-1) at the centreline and 0.020+/-0.004 m(2) s(-1) at midwing. The DPIV measurements suggest that if there is any spanwise flow in the LEV towards the end of the downstroke its velocity is less than 1 m s(-1). Estimates of force production show that the LEV contributes significantly to supporting body weight during bouts of flight at both speeds (more than 10% of body weight at 1.2 m s(-1) and 35-65% of body weight at 3.5 m s(-1)).

  15. Effect of Edge-Preserving Adaptive Image Filter on Low-Contrast Detectability in CT Systems: Application of ROC Analysis

    PubMed Central

    Okumura, Miwa; Ota, Takamasa; Kainuma, Kazuhisa; Sayre, James W.; McNitt-Gray, Michael; Katada, Kazuhiro

    2008-01-01

    Objective. For the multislice CT (MSCT) systems with a larger number of detector rows, it is essential to employ dose-reduction techniques. As reported in previous studies, edge-preserving adaptive image filters, which selectively eliminate only the noise elements that are increased when the radiation dose is reduced without affecting the sharpness of images, have been developed. In the present study, we employed receiver operating characteristic (ROC) analysis to assess the effects of the quantum denoising system (QDS), which is an edge-preserving adaptive filter that we have developed, on low-contrast resolution, and to evaluate to what degree the radiation dose can be reduced while maintaining acceptable low-contrast resolution. Materials and Methods. The low-contrast phantoms (Catphan 412) were scanned at various tube current settings, and ROC analysis was then performed for the groups of images obtained with/without the use of QDS at each tube current to determine whether or not a target could be identified. The tube current settings for which the area under the ROC curve (Az value) was approximately 0.7 were determined for both groups of images with/without the use of QDS. Then, the radiation dose reduction ratio when QDS was used was calculated by converting the determined tube current to the radiation dose. Results. The use of the QDS edge-preserving adaptive image filter allowed the radiation dose to be reduced by up to 38%. Conclusion. The QDS was found to be useful for reducing the radiation dose without affecting the low-contrast resolution in MSCT studies. PMID:19043565

  16. Development of a new metal artifact reduction algorithm by using an edge preserving method for CBCT imaging

    NASA Astrophysics Data System (ADS)

    Kim, Juhye; Nam, Haewon; Lee, Rena

    2015-07-01

    CT (computed tomography) images, metal materials such as tooth supplements or surgical clips can cause metal artifact and degrade image quality. In severe cases, this may lead to misdiagnosis. In this research, we developed a new MAR (metal artifact reduction) algorithm by using an edge preserving filter and the MATLAB program (Mathworks, version R2012a). The proposed algorithm consists of 6 steps: image reconstruction from projection data, metal segmentation, forward projection, interpolation