WorldWideScience

Sample records for acoustic imaging applied

  1. Acoustical Imaging

    CERN Document Server

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  2. Acoustical Imaging

    CERN Document Server

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  3. Acoustic imaging system

    Science.gov (United States)

    Smith, Richard W.

    1979-01-01

    An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

  4. Student design projects in applied acoustics.

    Science.gov (United States)

    Bös, Joachim; Moritz, Karsten; Skowronek, Adam; Thyes, Christian; Tschesche, Johannes; Hanselka, Holger

    2012-03-01

    This paper describes a series of student projects which are intended to complement theoretical education in acoustics and engineering noise control with practical experience. The projects are also intended to enhance the students' ability to work in a team, to manage a project, and to present their results. The projects are carried out in close cooperation with industrial partners so that the students can get a taste of the professional life of noise control engineers. The organization of such a project, its execution, and some of the results from the most recent student project are presented as a demonstrative example. This latest project involved the creation of noise maps of a production hall, the acoustic analysis of a packaging machine, and the acoustic analysis of a spiral vibratory conveyor. Upon completion of the analysis, students then designed, applied, and verified some simple preliminary noise reduction measures to demonstrate the potential of these techniques. © 2012 Acoustical Society of America

  5. MR imaging of acoustic neurinoma

    International Nuclear Information System (INIS)

    Miyamachi, Keikichi; Aida, Toshimitsu; Abe, Hiroshi; Nomura, Mikio; Saitou, Hisatoshi.

    1988-01-01

    Fifteen cases of acoustic neurinomas were studied by the use of a 0.15 T magnetic resonance (MR) imager. Three of the patients were male, and twelve were female. The patients' ages ranged from 23 to 67 years. The tumors were measured by means of MR images; the maximum was 37.5 mm across, and the minimum, 10 mm. The MR images of the acoustic neurinomas were hypointense on the T 1 -weighted images except in one case (isointense), while all cases were hyperintense on the T 2 -weighted images. MRI was much better than contrastenhanced CT for internal auditory canal (IAC) tumors (78 % versus 36 %), especially by means of coronal oblique image on T 2 -weighted images. In addition, MRI was more useful in demonstrating a VII - VIII neurocomplex on the non-affected side than was CT (57 % versus 10 %), but it did not demonstrate a VII - VIII neurocomplex on the affected side when a 0.15 T MR imager was used. It is very effective to separate the tumor from the tentorium cerebelli when it is necessary to differentiate an acoustic neurinoma from a meningioma at the cerebellopontine angle. A coronal or coronal oblique image offers information for use in separating the tentorium cerebelli. In small IAC tumors, the increased protein content of the cerebro-spinal fluid in an obstructed IAC and the bound-water effect in small collections of fluid may shorten the relaxation times of the trapped intracanalicular fluid, producing difficulty in the ability to diagnosis small tumors. To reveal cystic components, it was found to be effective to use Gd-DTPA or short-TR short-TE spin-echo images. (author)

  6. 30th International Acoustical Imaging Symposium

    CERN Document Server

    Jones, Joie; Lee, Hua

    2011-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place every two years since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2009 the 30th International Symposium on Acoustical Imaging was held in Monterey, CA, USA, March 1-4. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 30 in the Series contains an excellent collection of forty three papers presented in five major categories: Biomedical Imaging Acoustic Microscopy Non-Destructive Evaluation Systems Analysis Signal Analysis and Image Processing Audience Researchers in medical imaging and biomedical instrumentation experts.

  7. Acoustic 3D imaging of dental structures

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D.K. [Lawrence Livermore National Lab., CA (United States); Hume, W.R. [California Univ., Los Angeles, CA (United States); Douglass, G.D. [California Univ., San Francisco, CA (United States)

    1997-02-01

    Our goals for the first year of this three dimensional electodynamic imaging project was to determine how to combine flexible, individual addressable; preprocessing of array source signals; spectral extrapolation or received signals; acoustic tomography codes; and acoustic propagation modeling code. We investigated flexible, individually addressable acoustic array material to find the best match in power, sensitivity and cost and settled on PVDF sheet arrays and 3-1 composite material.

  8. Systematic Error of Acoustic Particle Image Velocimetry and Its Correction

    Directory of Open Access Journals (Sweden)

    Mickiewicz Witold

    2014-08-01

    Full Text Available Particle Image Velocimetry is getting more and more often the method of choice not only for visualization of turbulent mass flows in fluid mechanics, but also in linear and non-linear acoustics for non-intrusive visualization of acoustic particle velocity. Particle Image Velocimetry with low sampling rate (about 15Hz can be applied to visualize the acoustic field using the acquisition synchronized to the excitation signal. Such phase-locked PIV technique is described and used in experiments presented in the paper. The main goal of research was to propose a model of PIV systematic error due to non-zero time interval between acquisitions of two images of the examined sound field seeded with tracer particles, what affects the measurement of complex acoustic signals. Usefulness of the presented model is confirmed experimentally. The correction procedure, based on the proposed model, applied to measurement data increases the accuracy of acoustic particle velocity field visualization and creates new possibilities in observation of sound fields excited with multi-tonal or band-limited noise signals.

  9. Homotopy Based Reconstruction from Acoustic Images

    DEFF Research Database (Denmark)

    Sharma, Ojaswa

    of the inherent arrangement. The problem of reconstruction from arbitrary cross sections is a generic problem and is also shown to be solved here using the mathematical tool of continuous deformations. As part of a complete processing, segmentation using level set methods is explored for acoustic images and fast...... GPU (Graphics Processing Unit) based methods are suggested for a streaming computation on large volumes of data. Validation of results for acoustic images is not straightforward due to unavailability of ground truth. Accuracy figures for the suggested methods are provided using phantom object...

  10. Imaging and detection of mines from acoustic measurements

    Science.gov (United States)

    Witten, Alan J.; DiMarzio, Charles A.; Li, Wen; McKnight, Stephen W.

    1999-08-01

    A laboratory-scale acoustic experiment is described where a buried target, a hockey puck cut in half, is shallowly buried in a sand box. To avoid the need for source and receiver coupling to the host sand, an acoustic wave is generated in the subsurface by a pulsed laser suspended above the air-sand interface. Similarly, an airborne microphone is suspended above this interface and moved in unison with the laser. After some pre-processing of the data, reflections for the target, although weak, could clearly be identified. While the existence and location of the target can be determined by inspection of the data, its unique shape can not. Since target discrimination is important in mine detection, a 3D imaging algorithm was applied to the acquired acoustic data. This algorithm yielded a reconstructed image where the shape of the target was resolved.

  11. Subwavelength image manipulation through oblique and herringbone layered acoustic systems

    International Nuclear Information System (INIS)

    Li, Chunhui; Jia, Han; Ke, Manzhu; Li, Yixiang; Liu, Zhengyou

    2014-01-01

    In this paper, an oblique and a herringbone layered acoustic structure are experimentally and theoretically demonstrated to manipulate acoustic subwavelength images. An imaging resolution of less than one tenth of a wavelength is achieved with both optimized systems, and lateral image shift has been realized by an oblique layered system. The thicknesses of both the oblique and the herringbone layered acoustic systems are largely reduced through utilizing the oblique or herringbone wave propagation path instead of the vertical wave propagation path in the rectangular layered planar acoustic system. With smaller size and subwavelength image manipulation, the acoustic systems are more favourable for practical application. (paper)

  12. 28th International Acoustical Imaging Symposium

    CERN Document Server

    André, Michael P; Andre, Michael; Arnold, Walter; Bamber, Jeff; Burov, Valentin; Chubachi, Noriyoshi; Erikson, Kenneth; Ermert, Helmut; Fink, Mathias; Gan, Woon S; Granz, Bernd; Greenleaf, James; Hu, Jiankai; Jones, Joie P; Khuri-Yakub, Pierre; Laugier, Pascal; Lee, Hua; Lees, Sidney; Levin, Vadim M; Maev, Roman; Masotti, Leonardo; Nowicki, Andrzej; O’Brien, William; Prasad, Manika; Rafter, Patrick; Rouseff, Daniel; Thijssen, Johan; Tittmann, Bernard; Tortoli, Piero; Steen, Anton; Waag, Robert; Wells, Peter; Acoustical Imaging

    2007-01-01

    The International Acoustical Imaging Symposium has been held continuously since 1968 as a unique forum for advanced research, promoting the sharing of technology, developments, methods and theory among all areas of acoustics. The interdisciplinary nature of the Symposium and the wide international participation are two of its main strengths. Scientists from around the world present their papers in an informal environment conducive to lively discussion and cross-fertilization. The fact that a loyal community of scientists has supported this Series since 1968 is evidence of its impact on the field. The Symposium Series continues to thrive in a busy calendar of scientific meetings without the infrastructure of a professional society. It does so because those who attend and those who rely on the Proceedings as a well-known reference work acknowledge its value. This Volume 28 of the Proceedings likewise contains an excellent collection of papers presented in six major categories, offering both a broad perspective ...

  13. Synchrotron x-ray imaging of acoustic cavitation bubbles induced by acoustic excitation

    International Nuclear Information System (INIS)

    Jung, Sung Yong; Park, Han Wook; Park, Sung Ho; Lee, Sang Joon

    2017-01-01

    The cavitation induced by acoustic excitation has been widely applied in various biomedical applications because cavitation bubbles can enhance the exchanges of mass and energy. In order to minimize the hazardous effects of the induced cavitation, it is essential to understand the spatial distribution of cavitation bubbles. The spatial distribution of cavitation bubbles visualized by the synchrotron x-ray imaging technique is compared to that obtained with a conventional x-ray tube. Cavitation bubbles with high density in the region close to the tip of the probe are visualized using the synchrotron x-ray imaging technique, however, the spatial distribution of cavitation bubbles in the whole ultrasound field is not detected. In this study, the effects of the ultrasound power of acoustic excitation and working medium on the shape and density of the induced cavitation bubbles are examined. As a result, the synchrotron x-ray imaging technique is useful for visualizing spatial distributions of cavitation bubbles, and it could be used for optimizing the operation conditions of acoustic cavitation. (paper)

  14. High throughput imaging cytometer with acoustic focussing.

    Science.gov (United States)

    Zmijan, Robert; Jonnalagadda, Umesh S; Carugo, Dario; Kochi, Yu; Lemm, Elizabeth; Packham, Graham; Hill, Martyn; Glynne-Jones, Peter

    2015-10-31

    We demonstrate an imaging flow cytometer that uses acoustic levitation to assemble cells and other particles into a sheet structure. This technique enables a high resolution, low noise CMOS camera to capture images of thousands of cells with each frame. While ultrasonic focussing has previously been demonstrated for 1D cytometry systems, extending the technology to a planar, much higher throughput format and integrating imaging is non-trivial, and represents a significant jump forward in capability, leading to diagnostic possibilities not achievable with current systems. A galvo mirror is used to track the images of the moving cells permitting exposure times of 10 ms at frame rates of 50 fps with motion blur of only a few pixels. At 80 fps, we demonstrate a throughput of 208 000 beads per second. We investigate the factors affecting motion blur and throughput, and demonstrate the system with fluorescent beads, leukaemia cells and a chondrocyte cell line. Cells require more time to reach the acoustic focus than beads, resulting in lower throughputs; however a longer device would remove this constraint.

  15. Acoustic rhinometry (AR): An Alternative Method to Image Nasal Airway Geometry

    DEFF Research Database (Denmark)

    Straszek, Sune; Pedersen, O.F.

      ACOUSTIC RHINOMETRY (AR): AN ALTERNATIVE METHOD TO IMAGE NASAL AIRWAY GEOMETRY.  INTRODUCTION AND BACKGROUND:  In human studies the acoustic reflection technique was first applied to describe the area-distance relationship of the lower airways, but later the acoustic reflection technique appeared...... to be of more use in the description of nasal cavity geometry. Applied to human subjects AR has been applied to monitor the effect of corrective surgery and mucosal effects of pharmacological interventions. In recent years, however, AR has found use also in pharmacological studies in animals ranging in size...

  16. Efficacy of passive acoustic screening: implications for the design of imager and MR-suite.

    Science.gov (United States)

    Moelker, Adriaan; Vogel, Mika W; Pattynama, Peter M T

    2003-02-01

    To investigate the efficacy of passive acoustic screening in the magnetic resonance (MR) environment by reducing direct and indirect MR-related acoustic noise, both from the patient's and health worker's perspective. Direct acoustic noise refers to sound originating from the inner and outer shrouds of the MR imager, and indirect noise to acoustic reflections from the walls of the MR suite. Sound measurements were obtained inside the magnet bore (patient position) and at the entrance of the MR imager (health worker position). Inner and outer shrouds and walls were lined with thick layers of sound insulation to eliminate the direct and indirect acoustic pathways. Sound pressure levels (SPLs) and octave band frequencies were acquired during various MR imaging sequences at 1.5 T. Inside the magnet bore, direct acoustic noise radiating from the inner shroud was most relevant, with substantial reductions of up to 18.8 dB when using passive screening of the magnetic bore. At the magnet bore entrance, blocking acoustic noise from the outer shroud and reflections showed significant reductions of 4.5 and 2.8 dB, respectively, and 9.4 dB when simultaneously applied. Inner shroud coverage contributed minimally to the overall SPL reduction. Maximum noise reduction by passive acoustic screening can be achieved by reducing direct sound conduction through the inner and outer shrouds. Additional measures to optimize the acoustic properties of the MR suite have only little effect. Copyright 2003 Wiley-Liss, Inc.

  17. Magnetic resonance imaging of acoustic neurinomas

    International Nuclear Information System (INIS)

    Umezu, Hiromichi; Seki, Yojiro; Aiba, Tadashi; Takemori, Setsuko

    1991-01-01

    A restrospective review was made on magnetic resonance imaging (MRI) scans, preoperative neuro-otological findings, and surgical results for hearing preservation in 20 consecutive patients with histologically verified acoustic neurinomas. The maximum diameter of the tumor, both in the cerebellopontine angle (CPA) and internal auditory canal (IAC), were measured by MRI scans to classify tumor size. The signal intensity of acoustic neurinoma was equal to or lower than that of the adjacent pons on T 1 -weighted images and higher on T 2 -weighted images. After the administration of Gd-DTPA, tumors were markedly enhanced, which appeared homogeneous for small tumors and heterogeneous for large ones. There was no relationship between the degree of preoperative hearing loss and tumor size in either the CPA or the IAC. The larger the tumor in the CPA, however, the more often did the response to a caloric test disappear or decrease greatly. In contrast, there was no apparent correlation between the caloric response and tumor size in the IAC. Twelve patients (60%) had serviceable hearing (pure tone average loss 50%) preoperatively: the average tumor size in this group was similar to that in patients with poor or no hearing. These 12 patients were considered to be candidates for hearing preservation at surgery: 5 (41.7%) retained serviceable hearing postoperatively. A mean tumor size in the CPA was 11.8 mm for patients with postoperative serviceable hearing and 21.3 mm for those without it. Moreover, hearing was preserved postoperatively in all 4 patients with tumor less than 5 mm in the IAC. Thus, hearing preservation after surgery seemed to be closely related to tumor size. This study confirmed the value of MRI, providing information for the evaluation of hearing-preservation surgery. (N.K.)

  18. Noncontact ultrasound imaging applied to cortical bone phantoms

    OpenAIRE

    Bulman, J. B.; Ganezer, K. S.; Halcrow, P. W.; Neeson, Ian

    2012-01-01

    Purpose: The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statisti...

  19. Laser-induced acoustic imaging of underground objects

    Science.gov (United States)

    Li, Wen; DiMarzio, Charles A.; McKnight, Stephen W.; Sauermann, Gerhard O.; Miller, Eric L.

    1999-02-01

    This paper introduces a new demining technique based on the photo-acoustic interaction, together with results from photo- acoustic experiments. We have buried different types of targets (metal, rubber and plastic) in different media (sand, soil and water) and imaged them by measuring reflection of acoustic waves generated by irradiation with a CO2 laser. Research has been focused on the signal acquisition and signal processing. A deconvolution method using Wiener filters is utilized in data processing. Using a uniform spatial distribution of laser pulses at the ground's surface, we obtained 3D images of buried objects. The images give us a clear representation of the shapes of the underground objects. The quality of the images depends on the mismatch of acoustic impedance of the buried objects, the bandwidth and center frequency of the acoustic sensors and the selection of filter functions.

  20. Optimization of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Alberto Izquierdo Fuente

    2014-01-01

    Full Text Available On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced.

  1. Optimization of a Biometric System Based on Acoustic Images

    Science.gov (United States)

    Izquierdo Fuente, Alberto; Del Val Puente, Lara; Villacorta Calvo, Juan J.; Raboso Mateos, Mariano

    2014-01-01

    On the basis of an acoustic biometric system that captures 16 acoustic images of a person for 4 frequencies and 4 positions, a study was carried out to improve the performance of the system. On a first stage, an analysis to determine which images provide more information to the system was carried out showing that a set of 12 images allows the system to obtain results that are equivalent to using all of the 16 images. Finally, optimization techniques were used to obtain the set of weights associated with each acoustic image that maximizes the performance of the biometric system. These results improve significantly the performance of the preliminary system, while reducing the time of acquisition and computational burden, since the number of acoustic images was reduced. PMID:24616643

  2. Demonstration of acoustic source localization in air using single pixel compressive imaging

    Science.gov (United States)

    Rogers, Jeffrey S.; Rohde, Charles A.; Guild, Matthew D.; Naify, Christina J.; Martin, Theodore P.; Orris, Gregory J.

    2017-12-01

    Acoustic source localization often relies on large sensor arrays that can be electronically complex and have large data storage requirements to process element level data. Recently, the concept of a single-pixel-imager has garnered interest in the electromagnetics literature due to its ability to form high quality images with a single receiver paired with shaped aperture screens that allow for the collection of spatially orthogonal measurements. Here, we present a method for creating an acoustic analog to the single-pixel-imager found in electromagnetics for the purpose of source localization. Additionally, diffraction is considered to account for screen openings comparable to the acoustic wavelength. A diffraction model is presented and incorporated into the single pixel framework. In this paper, we explore the possibility of applying single pixel localization to acoustic measurements. The method is experimentally validated with laboratory measurements made in an air waveguide.

  3. Combination of acoustical radiosity and the image source method

    DEFF Research Database (Denmark)

    Koutsouris, Georgios I; Brunskog, Jonas; Jeong, Cheol-Ho

    2013-01-01

    A combined model for room acoustic predictions is developed, aiming to treat both diffuse and specular reflections in a unified way. Two established methods are incorporated: acoustical radiosity, accounting for the diffuse part, and the image source method, accounting for the specular part...

  4. Acoustic-noise-optimized diffusion-weighted imaging.

    Science.gov (United States)

    Ott, Martin; Blaimer, Martin; Grodzki, David M; Breuer, Felix A; Roesch, Julie; Dörfler, Arnd; Heismann, Björn; Jakob, Peter M

    2015-12-01

    This work was aimed at reducing acoustic noise in diffusion-weighted MR imaging (DWI) that might reach acoustic noise levels of over 100 dB(A) in clinical practice. A diffusion-weighted readout-segmented echo-planar imaging (EPI) sequence was optimized for acoustic noise by utilizing small readout segment widths to obtain low gradient slew rates and amplitudes instead of faster k-space coverage. In addition, all other gradients were optimized for low slew rates. Volunteer and patient imaging experiments were conducted to demonstrate the feasibility of the method. Acoustic noise measurements were performed and analyzed for four different DWI measurement protocols at 1.5T and 3T. An acoustic noise reduction of up to 20 dB(A) was achieved, which corresponds to a fourfold reduction in acoustic perception. The image quality was preserved at the level of a standard single-shot (ss)-EPI sequence, with a 27-54% increase in scan time. The diffusion-weighted imaging technique proposed in this study allowed a substantial reduction in the level of acoustic noise compared to standard single-shot diffusion-weighted EPI. This is expected to afford considerably more patient comfort, but a larger study would be necessary to fully characterize the subjective changes in patient experience.

  5. Near-field acoustic imaging based on Laplacian sparsity

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Daudet, Laurent

    2016-01-01

    We present a sound source identification method for near-field acoustic imaging of extended sources. The methodology is based on a wave superposition method (or equivalent source method) that promotes solutions with sparse higher order spatial derivatives. Instead of promoting direct sparsity......, and the validity of the wave extrapolation used for the reconstruction is examined. It is shown that this methodology can overcome conventional limits of spatial sampling, and is therefore valid for wide-band acoustic imaging of extended sources....

  6. Ultrasonic phased array with surface acoustic wave for imaging cracks

    Directory of Open Access Journals (Sweden)

    Yoshikazu Ohara

    2017-06-01

    Full Text Available To accurately measure crack lengths, we developed a real-time surface imaging method (SAW PA combining an ultrasonic phased array (PA with a surface acoustic wave (SAW. SAW PA using a Rayleigh wave with a high sensitivity to surface defects was implemented for contact testing using a wedge with the third critical angle that allows the Rayleigh wave to be generated. Here, to realize high sensitivity imaging, SAW PA was optimized in terms of the wedge and the imaging area. The improved SAW PA was experimentally demonstrated using a fatigue crack specimen made of an aluminum alloy. For further verification in more realistic specimens, SAW PA was applied to stainless-steel specimens with a fatigue crack and stress corrosion cracks (SCCs. The fatigue crack was visualized with a high signal-to-noise ratio (SNR and its length was measured with a high accuracy of better than 1 mm. The SCCs generated in the heat-affected zones (HAZs of a weld were successfully visualized with a satisfactory SNR, although responses at coarse grains appeared throughout the imaging area. The SCC lengths were accurately measured. The imaging results also precisely showed complicated distributions of SCCs, which were in excellent agreement with the optically observed distributions.

  7. Magnetic resonance imaging in 38 cases of acoustic tumors

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, Masafumi; Ohtsuka, Takashi; Seiki, Yoshikatsu; Matsumoto, Mikiro; Shibata, Iekado; Terao, Hideo [Toho Univ., Tokyo (Japan). School of Medicine; Kohno, Takeshi; Sanpei, Kenji; Mano, Isamu

    1989-08-01

    The value of magnetic resonance imaging (MRI) in the diagnosis of acoustic tumors was retrospectively assessed in 38 cases. A 0.15 Tesla permanent magnet and a 1.5 Tesla superconducting magnet were employed in 24 and 14 cases, respectively. Gadolinium diethlene triamine pentaacetic acid (Gd-DTPA), a paramagnetic contrast agent, was used in 10 cases. Acoustic tumors were identified in all cases. Small, medium, and large tumors were depicted with equal clarity by MRI and computed tomography (CT). However, tumor contour and extension, accompanying cysts, and brainstem displacement were more clarly visualized on MRI. The use of Gd-DTPA improved the quality of the MR images by markedly enhancing the acoustic tumors in all cases. In particular, detection of small acoustic tumors and intra- or paratumoral cysts was facilitated by the use of Gd-DTPA. The possibility of a correlation between acoustic tumor histology and MRI features was studied by calculation of the contrast to noise (C/N) ratio in 10 cases of acoustic tumor and 7 cases of meningioma. No definite correlation was demonstrated, but there appeared to be some difference in the C/N ratio between acoustic tumors and meningiomas. In three volunteers, MRI demonstrated intracanalicular nerves, separately. Because of its higher resolution, MRI can be expected to replace CT and air CT in the diagnosis of acoustic tumors. (author).

  8. Vibro-acoustic Imaging at the Breazeale Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James Arthur [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jewell, James Keith [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lee, James Edwin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    The INL is developing Vibro-acoustic imaging technology to characterize microstructure in fuels and materials in spent fuel pools and within reactor vessels. A vibro-acoustic development laboratory has been established at the INL. The progress in developing the vibro-acoustic technology at the INL is the focus of this report. A successful technology demonstration was performed in a working TRIGA research reactor. Vibro-acoustic imaging was performed in the reactor pool of the Breazeale reactor in late September of 2015. A confocal transducer driven at a nominal 3 MHz was used to collect the 60 kHz differential beat frequency induced in a spent TRIGA fuel rod and empty gamma tube located in the main reactor water pool. Data was collected and analyzed with the INLDAS data acquisition software using a short time Fourier transform.

  9. Synthetic Aperture Acoustic Imaging for Roadside Detection of Solid Objects

    Science.gov (United States)

    2014-11-20

    Testing I I I I Cinderblock Foam block Isometric and translucent view of the weighted foam block . .-.-; Weighted foam block Figure 2.3... concrete block (CB, Fig. 2.4). Conven- tional methods for identifying targets in a radar or acoustic imaging system (also known as Automatic Target...and curb, or than the grass-covered hill beyond the sidewalk. However, there is a strong acoustic return from a seam in the sidewalk concrete that runs

  10. Acoustic imaging in a water filled metallic pipe

    International Nuclear Information System (INIS)

    Kolbe, W.F.; Turko, B.T.; Leskovar, B.

    1984-04-01

    A method is described for the imaging of the interior of a water filled metallic pipe using acoustical techniques. The apparatus consists of an array of 20 acoustic transducers mounted circumferentially around the pipe. Each transducer is pulsed in sequence, and the echos resulting from bubbles in the interior are digitized and processed by a computer to generate an image. The electronic control and digitizing system and the software processing of the echo signals are described. The performance of the apparatus is illustrated by the imaging of simulated bubbles consisting of thin walled glass spheres suspended in the pipe

  11. Acoustic imaging in a water filled metallic pipe

    International Nuclear Information System (INIS)

    Kolbe, W.F.; Leskovar, B.; Turko, B.T.

    1985-01-01

    A method is described for the imaging of the interior of a water filled metallic pipe using acoustical techniques. The apparatus consists of an array of 20 acoustic transducers mounted circumferentially around the pipe. Each transducer is pulsed in sequence, and the echos resulting from bubbles in the interior are digitized and processed by a computer to generate an image. The electronic control and digitizing system and the software processing of the echo signals are described. The performance of the apparatus is illustrated by the imaging of simulated bubbles consisting of thin walled glass spheres suspended in the pipe

  12. Transmission mode acoustic time-reversal imaging for nondestructive evaluation

    Science.gov (United States)

    Lehman, Sean K.; Devaney, Anthony J.

    2002-11-01

    In previous ASA meetings and JASA papers, the extended and formalized theory of transmission mode time reversal in which the transceivers are noncoincident was presented. When combined with the subspace concepts of a generalized MUltiple SIgnal Classification (MUSIC) algorithm, this theory is used to form super-resolution images of scatterers buried in a medium. These techniques are now applied to ultrasonic nondestructive evaluation (NDE) of parts, and shallow subsurface seismic imaging. Results are presented of NDE experiments on metal and epoxy blocks using data collected from an adaptive ultrasonic array, that is, a ''time-reversal machine,'' at Lawrence Livermore National Laboratory. Also presented are the results of seismo-acoustic subsurface probing of buried hazardous waste pits at the Idaho National Engineering and Environmental Laboratory. [Work performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.] [Work supported in part by CenSSIS, the Center for Subsurface Sensing and Imaging Systems, under the Engineering Research Centers Program of the NSF (award number EEC-9986821) as well as from Air Force Contracts No. F41624-99-D6002 and No. F49620-99-C0013.

  13. Performance Evaluation of a Biometric System Based on Acoustic Images

    Science.gov (United States)

    Izquierdo-Fuente, Alberto; del Val, Lara; Jiménez, María I.; Villacorta, Juan J.

    2011-01-01

    An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side). Two Uniform Linear Arrays (ULA) with 15 λ/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR)/False Non-Match Rate (FNMR) parameters and the Receiver Operating Characteristic (ROC) curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications. PMID:22163708

  14. Performance Evaluation of a Biometric System Based on Acoustic Images

    Directory of Open Access Journals (Sweden)

    Juan J. Villacorta

    2011-10-01

    Full Text Available An acoustic electronic scanning array for acquiring images from a person using a biometric application is developed. Based on pulse-echo techniques, multifrequency acoustic images are obtained for a set of positions of a person (front, front with arms outstretched, back and side. Two Uniform Linear Arrays (ULA with 15 l/2-equispaced sensors have been employed, using different spatial apertures in order to reduce sidelobe levels. Working frequencies have been designed on the basis of the main lobe width, the grating lobe levels and the frequency responses of people and sensors. For a case-study with 10 people, the acoustic profiles, formed by all images acquired, are evaluated and compared in a mean square error sense. Finally, system performance, using False Match Rate (FMR/False Non-Match Rate (FNMR parameters and the Receiver Operating Characteristic (ROC curve, is evaluated. On the basis of the obtained results, this system could be used for biometric applications.

  15. Modified electron acoustic field and energy applied to observation data

    Energy Technology Data Exchange (ETDEWEB)

    Abdelwahed, H. G., E-mail: hgomaa-eg@yahoo.com, E-mail: hgomaa-eg@mans.edu.eg [College of Science and Humanitarian Studies, Physics Department, Prince Sattam Bin Abdul Aziz University, Alkharj 11942 (Saudi Arabia); Theoretical Physics Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt); El-Shewy, E. K. [Theoretical Physics Research Group, Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt)

    2016-08-15

    Improved electrostatic acoustic field and energy have been debated in vortex trapped hot electrons and fluid of cold electrons with pressure term plasmas. The perturbed higher-order modified-Korteweg-de Vries equation (PhomKdV) has been worked out. The effect of trapping and electron temperatures on the electro-field and energy properties in auroral plasmas has been inspected.

  16. Chirped or time modulated excitation compared to short pulses for photoacoustic imaging in acoustic attenuating media

    Science.gov (United States)

    Burgholzer, P.; Motz, C.; Lang, O.; Berer, T.; Huemer, M.

    2018-02-01

    In photoacoustic imaging, optically generated acoustic waves transport the information about embedded structures to the sample surface. Usually, short laser pulses are used for the acoustic excitation. Acoustic attenuation increases for higher frequencies, which reduces the bandwidth and limits the spatial resolution. One could think of more efficient waveforms than single short pulses, such as pseudo noise codes, chirped, or harmonic excitation, which could enable a higher information-transfer from the samples interior to its surface by acoustic waves. We used a linear state space model to discretize the wave equation, such as the Stoke's equation, but this method could be used for any other linear wave equation. Linear estimators and a non-linear function inversion were applied to the measured surface data, for onedimensional image reconstruction. The proposed estimation method allows optimizing the temporal modulation of the excitation laser such that the accuracy and spatial resolution of the reconstructed image is maximized. We have restricted ourselves to one-dimensional models, as for higher dimensions the one-dimensional reconstruction, which corresponds to the acoustic wave without attenuation, can be used as input for any ultrasound imaging method, such as back-projection or time-reversal method.

  17. Acoustic Angiography: A New Imaging Modality for Assessing Microvasculature Architecture

    Directory of Open Access Journals (Sweden)

    Ryan C. Gessner

    2013-01-01

    Full Text Available The purpose of this paper is to provide the biomedical imaging community with details of a new high resolution contrast imaging approach referred to as “acoustic angiography.” Through the use of dual-frequency ultrasound transducer technology, images acquired with this approach possess both high resolution and a high contrast-to-tissue ratio, which enables the visualization of microvascular architecture without significant contribution from background tissues. Additionally, volumetric vessel-tissue integration can be visualized by using b-mode overlays acquired with the same probe. We present a brief technical overview of how the images are acquired, followed by several examples of images of both healthy and diseased tissue volumes. 3D images from alternate modalities often used in preclinical imaging, contrast-enhanced micro-CT and photoacoustics, are also included to provide a perspective on how acoustic angiography has qualitatively similar capabilities to these other techniques. These preliminary images provide visually compelling evidence to suggest that acoustic angiography may serve as a powerful new tool in preclinical and future clinical imaging.

  18. Acoustic imaging of underground storage tank wastes

    International Nuclear Information System (INIS)

    Mech, S.J.

    1995-09-01

    Acoustics is a potential tool to determine the properties of high level wastes stored in Underground Storage Tanks. Some acoustic properties were successfully measured by a limited demonstration conducted in 114-TX. This accomplishment provides the basis for expanded efforts to qualify techniques which depend on the acoustic properties of tank wastes. This work is being sponsored by the Department of Energy under the Office of Science and Technology. In FY-1994, limited Tank Waste Remediation Systems EM-30 support was available at Hanford and Los Alamos National Laboratory. The Massachusetts Institute of Technology (MIT) and Earth Resources Laboratory (ERL) were engaged for analysis support, and Elohi Geophysics, Inc. for seismic testing services. Westinghouse-Hanford Company provided the testing and training, supplied the special engineering and safety analysis equipment and procedures, and provided the trained operators for the actual tank operations. On 11/9/94, limited in-tank tests were successfully conducted in tank 114-TX. This stabilized Single Shell Tank was reported as containing 16.8 feet of waste, the lower 6.28 feet of which contained interstitial liquid. Testing was conducted over the lower 12 feet, between two Liquid Observation Wells thirty feet apart. The ''quick-look'' data was reviewed on-site by MIT and Elohi

  19. Topology optimization applied to room acoustic problems and surface acoustic wave devices

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Sigmund, Ole; Jensen, Jakob Søndergaard

    can be minimized either by distribution of reflecting material in a design domain along the ceiling or by distribution of absorbing and reflecting material along all the walls for both 2D and 3D problems. It is also shown how the method can be used to design sound barriers. The main part...... in order to optimize more complicated SAW structures such as acoustic horns which focus the SAWs to a small area. [1] M. P. Bendsøe, O. Sigmund, “Topology optimization, theory, methods and applications”, Springer Verlag Berlin Heidelberg New York, 2nd edition, (2003). ISBN 3-540-42992-1. [2] J. S. Jensen......, Berlin, (2000). ISBN 3-540-67232-X. [5] M. M. de Lima Jr and P. V. Santos, “Modulation of photonic structures by surface acoustic waves”, Rep. Prog. Phys., 68 1639-1701 (2005)...

  20. Quantile Acoustic Vectors vs. MFCC Applied to Speaker Verification

    Directory of Open Access Journals (Sweden)

    Mayorga-Ortiz Pedro

    2014-02-01

    Full Text Available In this paper we describe speaker and command recognition related experiments, through quantile vectors and Gaussian Mixture Modelling (GMM. Over the past several years GMM and MFCC have become two of the dominant approaches for modelling speaker and speech recognition applications. However, memory and computational costs are important drawbacks, because autonomous systems suffer processing and power consumption constraints; thus, having a good trade-off between accuracy and computational requirements is mandatory. We decided to explore another approach (quantile vectors in several tasks and a comparison with MFCC was made. Quantile acoustic vectors are proposed for speaker verification and command recognition tasks and the results showed very good recognition efficiency. This method offered a good trade-off between computation times, characteristics vector complexity and overall achieved efficiency.

  1. Estimation of the Tool Condition by Applying the Wavelet Transform to Acoustic Emission Signals

    International Nuclear Information System (INIS)

    Gomez, M. P.; Piotrkowski, R.; Ruzzante, J. E.; D'Attellis, C. E.

    2007-01-01

    This work follows the search of parameters to evaluate the tool condition in machining processes. The selected sensing technique is acoustic emission and it is applied to a turning process of steel samples. The obtained signals are studied using the wavelet transformation. The tool wear level is quantified as a percentage of the final wear specified by the Standard ISO 3685. The amplitude and relevant scale obtained of acoustic emission signals could be related with the wear level

  2. An Applied Image Processing for Radiographic Testing

    International Nuclear Information System (INIS)

    Ratchason, Surasak; Tuammee, Sopida; Srisroal Anusara

    2005-10-01

    An applied image processing for radiographic testing (RT) is desirable because it decreases time-consuming, decreases the cost of inspection process that need the experienced workers, and improves the inspection quality. This paper presents the primary study of image processing for RT-films that is the welding-film. The proposed approach to determine the defects on weld-images. The BMP image-files are opened and developed by computer program that using Borland C ++ . The software has five main methods that are Histogram, Contrast Enhancement, Edge Detection, Image Segmentation and Image Restoration. Each the main method has the several sub method that are the selected options. The results showed that the effective software can detect defects and the varied method suit for the different radiographic images. Furthermore, improving images are better when two methods are incorporated

  3. Acoustic Emission Technique Applied in Textiles Mechanical Characterization

    Directory of Open Access Journals (Sweden)

    Rios-Soberanis Carlos Rolando

    2017-01-01

    Full Text Available The common textile architecture/geometry are woven, braided, knitted, stitch boded, and Z-pinned. Fibres in textile form exhibit good out-of-plane properties and good fatigue and impact resistance, additionally, they have better dimensional stability and conformability. Besides the nature of the textile, the architecture has a great role in the mechanical behaviour and mechanisms of damage in textiles, therefore damage mechanisms and mechanical performance in structural applications textiles have been a major concern. Mechanical damage occurs to a large extent during the service lifetime consequently it is vital to understand the material mechanical behaviour by identifying its mechanisms of failure such as onset of damage, crack generation and propagation. In this work, textiles of different architecture were used to manufacture epoxy based composites in order to study failure events under tensile load by using acoustic emission technique which is a powerful characterization tool due to its link between AE data and fracture mechanics, which makes this relation a very useful from the engineering point of view.

  4. Applied medical image processing a basic course

    CERN Document Server

    Birkfellner, Wolfgang

    2014-01-01

    A widely used, classroom-tested text, Applied Medical Image Processing: A Basic Course delivers an ideal introduction to image processing in medicine, emphasizing the clinical relevance and special requirements of the field. Avoiding excessive mathematical formalisms, the book presents key principles by implementing algorithms from scratch and using simple MATLAB®/Octave scripts with image data and illustrations on an accompanying CD-ROM or companion website. Organized as a complete textbook, it provides an overview of the physics of medical image processing and discusses image formats and data storage, intensity transforms, filtering of images and applications of the Fourier transform, three-dimensional spatial transforms, volume rendering, image registration, and tomographic reconstruction.

  5. Photo acoustic imaging: technology, systems and market trends

    Science.gov (United States)

    Faucheux, Marc; d'Humières, Benoît; Cochard, Jacques

    2017-03-01

    Although the Photo Acoustic effect was observed by Graham Bell in 1880, the first applications (gas analysis) occurred in 1970's using the required energetic light pulses from lasers. During mid 1990's medical imaging research begun to use Photo Acoustic effect and in vivo images were obtained in mid-2000. Since 2009, the number of patent related to Photo Acoustic Imaging (PAI) has dramatically increased. PAI machines for pre-clinical and small animal imaging have been being used in a routine way for several years. Based on its very interesting features (non-ionizing radiation, noninvasive, high depth resolution ratio, scalability, moderate price) and because it is able to deliver not only anatomical, but functional and molecular information, PAI is a very promising clinical imaging modality. It penetrates deeper into tissue than OCT (Optical Coherence Tomography) and provides a higher resolution than ultrasounds. The PAI is one of the most growing imaging modality and some innovative clinical systems are planned to be on market in 2017. Our study analyzes the different approaches such as photoacoustic computed tomography, 3D photoacoustic microscopy, multispectral photoacoustic tomography and endoscopy with the recent and tremendous technological progress over the past decade: advances in image reconstruction algorithms, laser technology, ultrasound detectors and miniaturization. We analyze which medical domains and applications are the most concerned and explain what should be the forthcoming medical system in the near future. We segment the market in four parts: Components and R&D, pre-clinical, analytics, clinical. We analyzed what should be, quantitatively and qualitatively, the PAI medical markets in each segment and its main trends. We point out the market accessibility (patents, regulations, clinical evaluations, clinical acceptance, funding). In conclusion, we explain the main market drivers and challenges to overcome and give a road map for medical

  6. Multi-crack imaging using nonclassical nonlinear acoustic method

    International Nuclear Information System (INIS)

    Zhang Lue; Zhang Ying; Liu Xiao-Zhou; Gong Xiu-Fen

    2014-01-01

    Solid materials with cracks exhibit the nonclassical nonlinear acoustical behavior. The micro-defects in solid materials can be detected by nonlinear elastic wave spectroscopy (NEWS) method with a time-reversal (TR) mirror. While defects lie in viscoelastic solid material with different distances from one another, the nonlinear and hysteretic stress—strain relation is established with Preisach—Mayergoyz (PM) model in crack zone. Pulse inversion (PI) and TR methods are used in numerical simulation and defect locations can be determined from images obtained by the maximum value. Since false-positive defects might appear and degrade the imaging when the defects are located quite closely, the maximum value imaging with a time window is introduced to analyze how defects affect each other and how the fake one occurs. Furthermore, NEWS-TR-NEWS method is put forward to improve NEWS-TR scheme, with another forward propagation (NEWS) added to the existing phases (NEWS and TR). In the added phase, scanner locations are determined by locations of all defects imaged in previous phases, so that whether an imaged defect is real can be deduced. NEWS-TR-NEWS method is proved to be effective to distinguish real defects from the false-positive ones. Moreover, it is also helpful to detect the crack that is weaker than others during imaging procedure. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Identifying Vulnerable Plaques with Acoustic Radiation Force Impulse Imaging

    Science.gov (United States)

    Doherty, Joshua Ryan

    The rupture of arterial plaques is the most common cause of ischemic complications including stroke, the fourth leading cause of death and number one cause of long term disability in the United States. Unfortunately, because conventional diagnostic tools fail to identify plaques that confer the highest risk, often a disabling stroke and/or sudden death is the first sign of disease. A diagnostic method capable of characterizing plaque vulnerability would likely enhance the predictive ability and ultimately the treatment of stroke before the onset of clinical events. This dissertation evaluates the hypothesis that Acoustic Radiation Force Impulse (ARFI) imaging can noninvasively identify lipid regions, that have been shown to increase a plaque's propensity to rupture, within carotid artery plaques in vivo. The work detailed herein describes development efforts and results from simulations and experiments that were performed to evaluate this hypothesis. To first demonstrate feasibility and evaluate potential safety concerns, finite- element method simulations are used to model the response of carotid artery plaques to an acoustic radiation force excitation. Lipid pool visualization is shown to vary as a function of lipid pool geometry and stiffness. A comparison of the resulting Von Mises stresses indicates that stresses induced by an ARFI excitation are three orders of magnitude lower than those induced by blood pressure. This thesis also presents the development of a novel pulse inversion harmonic tracking method to reduce clutter-imposed errors in ultrasound-based tissue displacement estimates. This method is validated in phantoms and was found to reduce bias and jitter displacement errors for a marked improvement in image quality in vivo. Lastly, this dissertation presents results from a preliminary in vivo study that compares ARFI imaging derived plaque stiffness with spatially registered composition determined by a Magnetic Resonance Imaging (MRI) gold standard

  8. The Chemical Percolation Devolatilization Model Applied to the Devolatilization of Coal in High Intensity Acoustic Fields

    Directory of Open Access Journals (Sweden)

    Veras Carlos A. G.

    2002-01-01

    Full Text Available The chemical percolation devolatilization model (CPD was extended for the prediction of drying and devolatilization of coal particles in high intensity acoustic fields found in Rijke tube reactors. The acoustic oscillations enhance the heat and mass transfer processes in the fuel bed as well as in the freeboard, above the grate. The results from simulations in a Rijke tube combustor have shown an increase in the rate of water evaporation and thermal degradation of the particles. The devolatilization model, based on chemical percolation, applied in pulsating regime allowed the dynamic prediction on the yields of CO, CO2, CH4, H2O, other light gases as well as tar which are important on ignition and stabilization of flames. The model predicted the quantity and form of nitrogen containing species generated during devolatilization, for which knowledge is strategically indispensable for reducing pollutant emissions (NOx in flames under acoustic excitation .

  9. Imaging and applied optics: introduction to the feature issue.

    Science.gov (United States)

    Zalevsky, Zeev; Arnison, Matthew R; Javidi, Bahram; Testorf, Markus

    2018-03-01

    This special issue of Applied Optics contains selected papers from OSA's Imaging Congress with particular emphasis on work from mathematics in imaging, computational optical sensing and imaging, imaging systems and applications, and 3D image acquisition and display.

  10. Multi-crack imaging using nonclassical nonlinear acoustic method

    Science.gov (United States)

    Zhang, Lue; Zhang, Ying; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2014-10-01

    Solid materials with cracks exhibit the nonclassical nonlinear acoustical behavior. The micro-defects in solid materials can be detected by nonlinear elastic wave spectroscopy (NEWS) method with a time-reversal (TR) mirror. While defects lie in viscoelastic solid material with different distances from one another, the nonlinear and hysteretic stress—strain relation is established with Preisach—Mayergoyz (PM) model in crack zone. Pulse inversion (PI) and TR methods are used in numerical simulation and defect locations can be determined from images obtained by the maximum value. Since false-positive defects might appear and degrade the imaging when the defects are located quite closely, the maximum value imaging with a time window is introduced to analyze how defects affect each other and how the fake one occurs. Furthermore, NEWS-TR-NEWS method is put forward to improve NEWS-TR scheme, with another forward propagation (NEWS) added to the existing phases (NEWS and TR). In the added phase, scanner locations are determined by locations of all defects imaged in previous phases, so that whether an imaged defect is real can be deduced. NEWS-TR-NEWS method is proved to be effective to distinguish real defects from the false-positive ones. Moreover, it is also helpful to detect the crack that is weaker than others during imaging procedure.

  11. Description and validation of a combination of acoustical radiosity and the image source method

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Jeong, Cheol-Ho; Brunskog, Jonas

    2014-01-01

    A model that combines image source modelling and acoustical radiosity with complex boundary con- ditions, thus including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Model (PARISM). It has been developed in order to be able...... to model both specular and diffuse reflections with complex-valued acoustical descriptions of the surfaces. This paper mainly describes the combination of the two models and the implementation of the angle dependent surface descriptions both in the image source model and in acoustical radiosity...

  12. Acoustic Imaging Frequency Dynamics of Ferroelectric Domains by Atomic Force Microscopy

    International Nuclear Information System (INIS)

    Kun-Yu, Zhao; Hua-Rong, Zeng; Hong-Zhang, Song; Sen-Xing, Hui; Guo-Rong, Li; Qing-Rui, Yin; Shimamura, Kiyoshi; Kannan, Chinna Venkadasamy; Villora, Encarnacion Antonia Garcia; Takekawa, Shunji; Kitamura, Kenji

    2008-01-01

    We report the acoustic imaging frequency dynamics of ferroelectric domains by low-frequency acoustic probe microscopy based on the commercial atomic force microscopy It is found that ferroelectric domain could be firstly visualized at lower frequency down to 0.5 kHz by AFM-based acoustic microscopy The frequency-dependent acoustic signal revealed a strong acoustic response in the frequency range from 7kHz to 10kHz, and reached maximum at 8.1kHz. The acoustic contrast mechanism can be ascribed to the different elastic response of ferroelectric microstructures to local elastic stress fields, which is induced by the acoustic wave transmitting in the sample when the piezoelectric transducer is vibrating and exciting acoustic wave under ac electric fields due to normal piezoelectric effects. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Applied acoustics concepts, absorbers, and silencers for acoustical comfort and noise control alternative solutions, innovative tools, practical examples

    CERN Document Server

    Fuchs, Helmut V

    2013-01-01

    The author gives a comprehensive overview of materials and components for noise control and acoustical comfort. Sound absorbers must meet acoustical and architectural requirements, which fibrous or porous material alone can meet. Basics and applications are demonstrated, with representative examples for spatial acoustics, free-field test facilities and canal linings. Acoustic engineers and construction professionals will find some new basic concepts and tools for developments in order to improve acoustical comfort. Interference absorbers, active resonators and micro-perforated absorbers of different materials and designs complete the list of applications.

  14. Synchronized imaging and acoustic analysis of the upper airway in patients with sleep-disordered breathing

    International Nuclear Information System (INIS)

    Chang, Yi-Chung; Pham, Van-Truong; Wang, Yung-Hung; Lin, Chen; Lo, Men-Tzung; Huon, Leh-Kiong; Wang, Pa-Chun; Chen, Yunn-Jy; Jiang, Sun-Fen; Shih, Tiffany Ting-Fang; Tran, Thi-Thao; Tsao, Jenho

    2014-01-01

    Progressive narrowing of the upper airway increases airflow resistance and can produce snoring sounds and apnea/hypopnea events associated with sleep-disordered breathing due to airway collapse. Recent studies have shown that acoustic properties during snoring can be altered with anatomic changes at the site of obstruction. To evaluate the instantaneous association between acoustic features of snoring and the anatomic sites of obstruction, a novel method was developed and applied in nine patients to extract the snoring sounds during sleep while performing dynamic magnetic resonance imaging (MRI). The degree of airway narrowing during the snoring events was then quantified by the collapse index (ratio of airway diameter preceding and during the events) and correlated with the synchronized acoustic features. A total of 201 snoring events (102 pure retropalatal and 99 combined retropalatal and retroglossal events) were recorded, and the collapse index as well as the soft tissue vibration time were significantly different between pure retropalatal (collapse index, 24  ±  11%; vibration time, 0.2  ±  0.3 s) and combined (retropalatal and retroglossal) snores (collapse index, 13  ±  7% [P ≤ 0.0001]; vibration time, 1.2  ±  0.7 s [P ≤ 0.0001]). The synchronized dynamic MRI and acoustic recordings successfully characterized the sites of obstruction and established the dynamic relationship between the anatomic site of obstruction and snoring acoustics. (paper)

  15. Spatial distribution of macroalgae along the shores of Kongsfjorden (West Spitsbergen using acoustic imaging

    Directory of Open Access Journals (Sweden)

    Kruss Aleksandra

    2017-06-01

    Full Text Available The identification of macroalgal beds is a crucial component for the description of fjord ecosystems. Direct, biological sampling is still the most popular investigation technique but acoustic methods are becoming increasingly recognized as a very efficient tool for the assessment of benthic communities. In 2007 we carried out the first acoustic survey of the littoral areas in Kongsfjorden. A 2.68 km2 area comprised within a 12.40 km2 euphotic zone was mapped along the fjord’s coast using single- and multi-beam echosounders. The singlebeam echosounder (SBES proved to be a very efficient and reliable tool for macroalgae detection in Arctic conditions. The multibeam echosounder (MBES was very useful in extending the SBES survey range, even though it’s ability in discriminating benthic communities was limited. The final result of our investigation is a map of the macroalgae distribution around the fjord, showing 39% macroalgae coverage (1.09 km2 of investigated area between isobaths -0.70 m and -30 m. Zonation analysis showed that most of the studied macroalgae areas occur up to 15 m depth (93%. These results were confirmed by biological sampling and observation in key areas. The potential of acoustic imaging of macrophytes, and a proposed methodology for the processing of acoustic data, are presented in this paper along with preliminary studies on the acoustic reflectivity of macroalgae, also highlighting differences among species. These results can be applied to future monitoring of the evolution of kelp beds in different areas of the Arctic, and in the rest of the world.

  16. Imaging of heart acoustic based on the sub-space methods using a microphone array.

    Science.gov (United States)

    Moghaddasi, Hanie; Almasganj, Farshad; Zoroufian, Arezoo

    2017-07-01

    Heart disease is one of the leading causes of death around the world. Phonocardiogram (PCG) is an important bio-signal which represents the acoustic activity of heart, typically without any spatiotemporal information of the involved acoustic sources. The aim of this study is to analyze the PCG by employing a microphone array by which the heart internal sound sources could be localized, too. In this paper, it is intended to propose a modality by which the locations of the active sources in the heart could also be investigated, during a cardiac cycle. In this way, a microphone array with six microphones is employed as the recording set up to be put on the human chest. In the following, the Group Delay MUSIC algorithm which is a sub-space based localization method is used to estimate the location of the heart sources in different phases of the PCG. We achieved to 0.14cm mean error for the sources of first heart sound (S 1 ) simulator and 0.21cm mean error for the sources of second heart sound (S 2 ) simulator with Group Delay MUSIC algorithm. The acoustical diagrams created for human subjects show distinct patterns in various phases of the cardiac cycles such as the first and second heart sounds. Moreover, the evaluated source locations for the heart valves are matched with the ones that are obtained via the 4-dimensional (4D) echocardiography applied, to a real human case. Imaging of heart acoustic map presents a new outlook to indicate the acoustic properties of cardiovascular system and disorders of valves and thereby, in the future, could be used as a new diagnostic tool. Copyright © 2017. Published by Elsevier B.V.

  17. Magneto-thermal-acoustic differential-frequency imaging of magnetic nanoparticle with magnetic spatial localization: a theoretical prediction

    Science.gov (United States)

    Piao, Daqing

    2017-02-01

    The magneto-thermo-acoustic effect that we predicted in 2013 refers to the generation of acoustic-pressure wave from magnetic nanoparticle (MNP) when thermally mediated under an alternating magnetic field (AMF) at a pulsed or frequency-chirped application. Several independent experimental studies have since validated magneto-thermoacoustic effect, and a latest report has discovered acoustic-wave generation from MNP at the second-harmonic frequency of the AMF when operating continuously. We propose that applying two AMFs with differing frequencies to MNP will produce acoustic-pressure wave at the summation and difference of the two frequencies, in addition to the two second-harmonic frequencies. Analysis of the specific absorption dynamics of the MNP when exposed to two AMFs of differing frequencies has shown some interesting patterns of acoustic-intensity at the multiple frequency components. The ratio of the acoustic-intensity at the summation-frequency over that of the difference-frequency is determined by the frequency-ratio of the two AMFs, but remains independent of the AMF strengths. The ratio of the acoustic-intensity at the summation- or difference-frequency over that at each of the two second-harmonic frequencies is determined by both the frequency-ratio and the field-strength-ratio of the two AMFs. The results indicate a potential strategy for localization of the source of a continuous-wave magneto-thermalacoustic signal by examining the frequency spectrum of full-field non-differentiating acoustic detection, with the field-strength ratio changed continuously at a fixed frequency-ratio. The practicalities and challenges of this magnetic spatial localization approach for magneto-thermo-acoustic imaging using a simple envisioned set of two AMFs arranged in parallel to each other are discussed.

  18. Effect of externally applied periodic force on ion acoustic waves in superthermal plasmas

    Science.gov (United States)

    Chowdhury, Snigdha; Mandi, Laxmikanta; Chatterjee, Prasanta

    2018-04-01

    Ion acoustic solitary waves in superthermal plasmas are investigated in the presence of trapped electrons. The reductive perturbation technique is employed to obtain a forced Korteweg-de Vries-like Schamel equation. An analytical solution is obtained in the presence of externally applied force. The effect of the external applied periodic force is also observed. The effect of the spectral index (κ), the strength ( f 0 ) , and the frequency ( ω ) on the amplitude and width of the solitary wave is obtained. The result may be useful in laboratory plasma as well as space environments.

  19. Acoustic resonances in microfluidic chips: full-image micro-PIV experiments and numerical simulations.

    Science.gov (United States)

    Hagsäter, S M; Jensen, T Glasdam; Bruus, H; Kutter, J P

    2007-10-01

    We show that full-image micro-PIV analysis in combination with images of transient particle motion is a powerful tool for experimental studies of acoustic radiation forces and acoustic streaming in microfluidic chambers under piezo-actuation in the MHz range. The measured steady-state motion of both large 5 microm and small 1 microm particles can be understood in terms of the acoustic eigenmodes or standing ultra-sound waves in the given experimental microsystems. This interpretation is supported by numerical solutions of the corresponding acoustic wave equation.

  20. Auralisations with loudspeaker arrays from a phased combination of the image source method and acoustical radiosity

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy

    2017-01-01

    In order to create a simulation tool that is well-suited for small rooms with low diffusion and highly absorbing ceilings, a new room acoustic simulation tool has been developed that combines a phased version of the image source with acoustical radiosity and that considers the angle dependence...... impulse response, because more directional information is available with acoustical radiosity. Small rooms with absorbing surfaces are tested, because this is the room type that PARISM is particularly useful for....

  1. Auralizations with loudspeaker arrays from a phased combination of the image source method and acoustical radiosity

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2017-01-01

    In order to create a simulation tool that is well-suited for small rooms with low diffusion and highly absorbing ceilings, a new room acoustic simulation tool has been developed that combines a phased version of the image source with acoustical radiosity and that considers the angle dependence...... of the PARISM impulse response, because more directional information is available with acoustical radiosity. Small rooms with absorbing surfaces are tested, because this is the room type that PARISM is particularly useful for....

  2. Acoustic sources of opportunity in the marine environment - Applied to source localization and ocean sensing

    Science.gov (United States)

    Verlinden, Christopher M.

    Controlled acoustic sources have typically been used for imaging the ocean. These sources can either be used to locate objects or characterize the ocean environment. The processing involves signal extraction in the presence of ambient noise, with shipping being a major component of the latter. With the advent of the Automatic Identification System (AIS) which provides accurate locations of all large commercial vessels, these major noise sources can be converted from nuisance to beacons or sources of opportunity for the purpose of studying the ocean. The source localization method presented here is similar to traditional matched field processing, but differs in that libraries of data-derived measured replicas are used in place of modeled replicas. In order to account for differing source spectra between library and target vessels, cross-correlation functions are compared instead of comparing acoustic signals directly. The library of measured cross-correlation function replicas is extrapolated using waveguide invariant theory to fill gaps between ship tracks, fully populating the search grid with estimated replicas allowing for continuous tracking. In addition to source localization, two ocean sensing techniques are discussed in this dissertation. The feasibility of estimating ocean sound speed and temperature structure, using ship noise across a drifting volumetric array of hydrophones suspended beneath buoys, in a shallow water marine environment is investigated. Using the attenuation of acoustic energy along eigenray paths to invert for ocean properties such as temperature, salinity, and pH is also explored. In each of these cases, the theory is developed, tested using numerical simulations, and validated with data from acoustic field experiments.

  3. A combination of the acoustic radiosity and the image source method

    DEFF Research Database (Denmark)

    Koutsouris, Georgios I.; Brunskog, Jonas; Jeong, Cheol-Ho

    2012-01-01

    A combined model for room acoustic predictions is developed, aiming to treat both diffuse and specular reflections in a unified way. Two established methods are incorporated: acoustical radiosity, accounting for the diffuse part, and the image source method, accounting for the specular part...

  4. Comparing a phased combination of acoustical radiosity and the image source method with other simulation tools

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2015-01-01

    A phased combination of acoustical radiosity and the image source method (PARISM) has been developed in order to be able to model both specular and diffuse reflections with angle-dependent and complex-valued acoustical descriptions of the surfaces. It is of great interest to model both specular...

  5. Platforms for hyperspectral imaging, in-situ optical and acoustical imaging in urbanized regions

    Science.gov (United States)

    Bostater, Charles R.; Oney, Taylor

    2016-10-01

    Hyperspectral measurements of the water surface of urban coastal waters are presented. Oblique bidirectional reflectance factor imagery was acquired made in a turbid coastal sub estuary of the Indian River Lagoon, Florida and along coastal surf zone waters of the nearby Atlantic Ocean. Imagery was also collected using a pushbroom hyperspectral imager mounted on a fixed platform with a calibrated circular mechatronic rotation stage. Oblique imagery of the shoreline and subsurface features clearly shows subsurface bottom features and rip current features within the surf zone water column. In-situ hyperspectral optical signatures were acquired from a vessel as a function of depth to determine the attenuation spectrum in Palm Bay. A unique stationary platform methodology to acquire subsurface acoustic images showing the presence of moving bottom boundary nephelometric layers passing through the acoustic fan beam. The acoustic fan beam imagery indicated the presence of oscillatory subsurface waves in the urbanized coastal estuary. Hyperspectral imaging using the fixed platform techniques are being used to collect hyperspectral bidirectional reflectance factor (BRF) measurements from locations at buildings and bridges in order to provide new opportunities to advance our scientific understanding of aquatic environments in urbanized regions.

  6. Acoustic multimode interference and self-imaging phenomena realized in multimodal phononic crystal waveguides

    International Nuclear Information System (INIS)

    Zou, Qiushun; Yu, Tianbao; Liu, Jiangtao; Wang, Tongbiao; Liao, Qinghua; Liu, Nianhua

    2015-01-01

    We report an acoustic multimode interference effect and self-imaging phenomena in an acoustic multimode waveguide system which consists of M parallel phononic crystal waveguides (M-PnCWs). Results show that the self-imaging principle remains applicable for acoustic waveguides just as it does for optical multimode waveguides. To achieve the dispersions and replicas of the input acoustic waves produced along the propagation direction, we performed the finite element method on M-PnCWs, which support M guided modes within the target frequency range. The simulation results show that single images (including direct and mirrored images) and N-fold images (N is an integer) are identified along the propagation direction with asymmetric and symmetric incidence discussed separately. The simulated positions of the replicas agree well with the calculated values that are theoretically decided by self-imaging conditions based on the guided mode propagation analysis. Moreover, the potential applications based on this self-imaging effect for acoustic wavelength de-multiplexing and beam splitting in the acoustic field are also presented. (paper)

  7. Development of novel imaging probe for optical/acoustic radiation imaging (OARI).

    Science.gov (United States)

    Ejofodomi, O'tega A; Zderic, Vesna; Zara, Jason M

    2013-11-01

    Optical/acoustic radiation imaging (OARI) is a novel imaging modality being developed to interrogate the optical and mechanical properties of soft tissues. OARI uses acoustic radiation force to generate displacement in soft tissue. Optical images before and after the application of the force are used to generate displacement maps that provide information about the mechanical properties of the tissue under interrogation. Since the images are optical images, they also represent the optical properties of the tissue as well. In this paper, the authors present the first imaging probe that uses acoustic radiation force in conjunction with optical coherence tomography (OCT) to provide information about the optical and mechanical properties of tissues to assist in the diagnosis and staging of epithelial cancers, and in particular bladder cancer. The OARI prototype probe consisted of an OCT probe encased in a plastic sheath, a miniaturized transducer glued to a plastic holder, both of which were encased in a 10 cm stainless steel tube with an inner diameter of 10 mm. The transducer delivered an acoustic intensity of 18 W/cm(2) and the OCT probe had a spatial resolution of approximately 10-20 μm. The tube was filled with deionized water for acoustic coupling and covered by a low density polyethylene cap. The OARI probe was characterized and tested on bladder wall phantoms. The phantoms possessed Young's moduli ranging from 10.2 to 12 kPa, mass density of 1.05 g/cm(3), acoustic attenuation coefficient of 0.66 dB/cm MHz, speed of sound of 1591 m/s, and optical scattering coefficient of 1.80 mm(-1). Finite element model (FEM) theoretical simulations were performed to assess the performance of the OARI probe. The authors obtained displacements of 9.4, 8.7, and 3.4 μm for the 3%, 4%, and 5% bladder wall phantoms, respectively. This shows that the probe is capable of generating optical images, and also has the ability to generate and track displacements in tissue. This will

  8. Detection of Breast Microcalcifications Under Ultrasound Using Power Doppler and Acoustic Resonance Imaging

    National Research Council Canada - National Science Library

    Weinstein, Susan

    2003-01-01

    .... Our goal with our current project was to utilize breast sonography coupled with the technique of acoustic resonance to image and evaluate the breast micorcalcifications in patients prior to biopsy...

  9. Negative refraction imaging of acoustic metamaterial lens in the supersonic range

    Directory of Open Access Journals (Sweden)

    Jianning Han

    2014-05-01

    Full Text Available Acoustic metamaterials with negative refraction index is the most promising method to overcome the diffraction limit of acoustic imaging to achieve ultrahigh resolution. In this paper, we use localized resonant phononic crystal as the unit cell to construct the acoustic negative refraction lens. Based on the vibration model of the phononic crystal, negative quality parameters of the lens are obtained while excited near the system resonance frequency. Simulation results show that negative refraction of the acoustic lens can be achieved when a sound wave transmiting through the phononic crystal plate. The patterns of the imaging field agree well with that of the incident wave, while the dispersion is very weak. The unit cell size in the simulation is 0.0005 m and the wavelength of the sound source is 0.02 m, from which we show that acoustic signal can be manipulated through structures with dimensions much smaller than the wavelength of incident wave.

  10. Tracking Energy Flow Using a Volumetric Acoustic Intensity Imager (VAIM)

    Science.gov (United States)

    Klos, Jacob; Williams, Earl G.; Valdivia, Nicolas P.

    2006-01-01

    A new measurement device has been invented at the Naval Research Laboratory which images instantaneously the intensity vector throughout a three-dimensional volume nearly a meter on a side. The measurement device consists of a nearly transparent spherical array of 50 inexpensive microphones optimally positioned on an imaginary spherical surface of radius 0.2m. Front-end signal processing uses coherence analysis to produce multiple, phase-coherent holograms in the frequency domain each related to references located on suspect sound sources in an aircraft cabin. The analysis uses either SVD or Cholesky decomposition methods using ensemble averages of the cross-spectral density with the fixed references. The holograms are mathematically processed using spherical NAH (nearfield acoustical holography) to convert the measured pressure field into a vector intensity field in the volume of maximum radius 0.4 m centered on the sphere origin. The utility of this probe is evaluated in a detailed analysis of a recent in-flight experiment in cooperation with Boeing and NASA on NASA s Aries 757 aircraft. In this experiment the trim panels and insulation were removed over a section of the aircraft and the bare panels and windows were instrumented with accelerometers to use as references for the VAIM. Results show excellent success at locating and identifying the sources of interior noise in-flight in the frequency range of 0 to 1400 Hz. This work was supported by NASA and the Office of Naval Research.

  11. Terahertz imaging applied to cancer diagnosis

    Science.gov (United States)

    Brun, M.-A.; Formanek, F.; Yasuda, A.; Sekine, M.; Ando, N.; Eishii, Y.

    2010-08-01

    We report on terahertz (THz) time-domain spectroscopy imaging of 10 µm thick histological sections. The sections are prepared according to standard pathological procedures and deposited on a quartz window for measurements in reflection geometry. Simultaneous acquisition of visible images enables registration of THz images and thus the use of digital pathology tools to investigate the links between the underlying cellular structure and specific THz information. An analytic model taking into account the polarization of the THz beam, its incidence angle, the beam shift between the reference and sample pulses as well as multiple reflections within the sample is employed to determine the frequency-dependent complex refractive index. Spectral images are produced through segmentation of the extracted refractive index data using clustering methods. Comparisons of visible and THz images demonstrate spectral differences not only between tumor and healthy tissues but also within tumors. Further visualization using principal component analysis suggests different mechanisms as to the origin of image contrast.

  12. Terahertz imaging applied to cancer diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Brun, M-A; Formanek, F; Yasuda, A [Life Science Laboratory, Advanced Materials Laboratories, Sony Corporation, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510 (Japan); Sekine, M; Ando, N; Eishii, Y, E-mail: florian.formanek@jp.sony.co [Department of Human Pathology, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510 (Japan)

    2010-08-21

    We report on terahertz (THz) time-domain spectroscopy imaging of 10 {mu}m thick histological sections. The sections are prepared according to standard pathological procedures and deposited on a quartz window for measurements in reflection geometry. Simultaneous acquisition of visible images enables registration of THz images and thus the use of digital pathology tools to investigate the links between the underlying cellular structure and specific THz information. An analytic model taking into account the polarization of the THz beam, its incidence angle, the beam shift between the reference and sample pulses as well as multiple reflections within the sample is employed to determine the frequency-dependent complex refractive index. Spectral images are produced through segmentation of the extracted refractive index data using clustering methods. Comparisons of visible and THz images demonstrate spectral differences not only between tumor and healthy tissues but also within tumors. Further visualization using principal component analysis suggests different mechanisms as to the origin of image contrast.

  13. Electronic imaging applied to neutron radiography

    International Nuclear Information System (INIS)

    Garrett, D.A.; Bracher, D.A.

    1976-01-01

    A commercially - available image intensifier was used with a scan conversion memory and a mobile 252 Cf based neutron radiography system to obtain neutron radiographs on a television monitor in 0.5 minutes to 10.0 minutes

  14. APES Beamforming Applied to Medical Ultrasound Imaging

    DEFF Research Database (Denmark)

    Blomberg, Ann E. A.; Holfort, Iben Kraglund; Austeng, Andreas

    2009-01-01

    Recently, adaptive beamformers have been introduced to medical ultrasound imaging. The primary focus has been on the minimum variance (MV) (or Capon) beamformer. This work investigates an alternative but closely related beamformer, the Amplitude and Phase Estimation (APES) beamformer. APES offers...... added robustness at the expense of a slightly lower resolution. The purpose of this study was to evaluate the performance of the APES beamformer on medical imaging data, since correct amplitude estimation often is just as important as spatial resolution. In our simulations we have used a 3.5 MHz, 96...... element linear transducer array. When imaging two closely spaced point targets, APES displays nearly the same resolution as the MV, and at the same time improved amplitude control. When imaging cysts in speckle, APES offers speckle statistics similar to that of the DAS, without the need for temporal...

  15. Applying Image Matching to Video Analysis

    Science.gov (United States)

    2010-09-01

    image groups, classified by the background scene, are the flag, the kitchen, the telephone, the bookshelf , the title screen, the...Kitchen 136 Telephone 3 Bookshelf 81 Title Screen 10 Map 1 24 Map 2 16 command line. This implementation of a Bloom filter uses two arbitrary...with the Bookshelf images. This scene is a much closer shot than the Kitchen scene so the host occupies much of the background. Algorithms for face

  16. Preliminary study of copper oxide nanoparticles acoustic and magnetic properties for medical imaging

    Science.gov (United States)

    Perlman, Or; Weitz, Iris S.; Azhari, Haim

    2015-03-01

    The implementation of multimodal imaging in medicine is highly beneficial as different physical properties may provide complementary information, augmented detection ability, and diagnosis verification. Nanoparticles have been recently used as contrast agents for various imaging modalities. Their significant advantage over conventional large-scale contrast agents is the ability of detection at early stages of the disease, being less prone to obstacles on their path to the target region, and possible conjunction to therapeutics. Copper ions play essential role in human health. They are used as a cofactor for multiple key enzymes involved in various fundamental biochemistry processes. Extremely small size copper oxide nanoparticles (CuO-NPs) are readily soluble in water with high colloidal stability yielding high bioavailability. The goal of this study was to examine the magnetic and acoustic characteristics of CuO-NPs in order to evaluate their potential to serve as contrast imaging agent for both MRI and ultrasound. CuO-NPs 7nm in diameter were synthesized by hot solution method. The particles were scanned using a 9.4T MRI and demonstrated a concentration dependent T1 relaxation time shortening phenomenon. In addition, it was revealed that CuO-NPs can be detected using the ultrasonic B-scan imaging. Finally, speed of sound based ultrasonic computed tomography was applied and showed that CuO-NPs can be clearly imaged. In conclusion, the preliminary results obtained, positively indicate that CuO-NPs may be imaged by both MRI and ultrasound. The results motivate additional in-vivo studies, in which the clinical utility of fused images derived from both modalities for diagnosis improvement will be studied.

  17. Noncontact ultrasound imaging applied to cortical bone phantoms.

    Science.gov (United States)

    Bulman, J B; Ganezer, K S; Halcrow, P W; Neeson, Ian

    2012-06-01

    The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statistical and systematic errors associated with the variability in the pressure applied by the clinician to the transmitting transducer that NCU might provide. The authors also undertook this study in order to find additional applications of NCU beyond its past limited usage in assessing the severity of third degree burns. A noncontact ultrasound imaging system using a pair of specially designed broadband, 1.5 MHz noncontact piezoelectric transducers and cortical bone phantoms, were used to determine bone mineral density (BMD), speed of sound (SOS), integrated response (IR), and ultrasonic transmittance. Air gaps of greater than 3 cm, two transmission and two reflection paths, and a digital signal processor were also used in the collection of data from phantoms of nominal mass densities that varied from 1.17 to 2.25 g/cm(3) and in bone mineral density from 0 to 1.7 g/cm(3). Good correlations between known BMD and measured SOS, IR, and transmittance were obtained for all 17 phantoms, and methods for quantifying and minimizing sources of systematic errors were outlined. The BMD of the phantom sets extended through most of the in vivo range found in cortical bone. A total of 16-20 repeated measurements of the SOS, thickness, and IR for the phantom set that were conducted over a period of several months showed a small variation in the range of measurements of ±1%-2%. These NCU data were shown to be in agreement with similar results using contact ultrasound to be within 1%-2%. Transmittance

  18. Applying of the array transducers' technology for surface acoustic waves materials characterization in the transient regime

    International Nuclear Information System (INIS)

    Frenet, D.

    2000-01-01

    In this document we present a theoretical and experimental study which has been led to design a surface acoustic wave device for local characterisation (relatively to the wavelength) of isotropic or anisotropic materials. The device is based on a phased-array transducer of conical shape we have specifically designed for this purpose. It operates in the impulsive mode, in the frequency range of 1-5 MHz. In order to deduce mechanical properties of the material, it is possible to measure the surface wave characteristics (velocity, attenuation,...). Different methods for measuring the wave velocity have been developed taking advantage of from the phased-array technology. The originality of theses methods relies on the fact that the measures are performed without moving the transducer. Consequently, the device requires no additional mechanical system and it is quite compact. In addition, this shortens the characterisation process duration comparatively to the usually available methods (e. g. the V(z) technique). In the theoretical section of this study, a versatile model allowing to simulate in the time harmonic regime as well as in the transient regime, the transmitted field, the field reflected on isotropic or anisotropic planar samples and the output voltage for transducers of arbitrary shapes has been developed. The model has been applied to the phased-array conical transducer as well as to more classical transducers such as planar (rectangular) or focusing (spherically or cylindrically shaped) transducers. It predicts not only the geometrical contributions of the reflected field and signal but also the leaky contributions related to the surface acoustic waves. (author)

  19. High-spatial-resolution sub-surface imaging using a laser-based acoustic microscopy technique.

    Science.gov (United States)

    Balogun, Oluwaseyi; Cole, Garrett D; Huber, Robert; Chinn, Diane; Murray, Todd W; Spicer, James B

    2011-01-01

    Scanning acoustic microscopy techniques operating at frequencies in the gigahertz range are suitable for the elastic characterization and interior imaging of solid media with micrometer-scale spatial resolution. Acoustic wave propagation at these frequencies is strongly limited by energy losses, particularly from attenuation in the coupling media used to transmit ultrasound to a specimen, leading to a decrease in the depth in a specimen that can be interrogated. In this work, a laser-based acoustic microscopy technique is presented that uses a pulsed laser source for the generation of broadband acoustic waves and an optical interferometer for detection. The use of a 900-ps microchip pulsed laser facilitates the generation of acoustic waves with frequencies extending up to 1 GHz which allows for the resolution of micrometer-scale features in a specimen. Furthermore, the combination of optical generation and detection approaches eliminates the use of an ultrasonic coupling medium, and allows for elastic characterization and interior imaging at penetration depths on the order of several hundred micrometers. Experimental results illustrating the use of the laser-based acoustic microscopy technique for imaging micrometer-scale subsurface geometrical features in a 70-μm-thick single-crystal silicon wafer with a (100) orientation are presented.

  20. Acoustic noise reduction in T 1- and proton-density-weighted turbo spin-echo imaging.

    Science.gov (United States)

    Ott, Martin; Blaimer, Martin; Breuer, Felix; Grodzki, David; Heismann, Björn; Jakob, Peter

    2016-02-01

    To reduce acoustic noise levels in T 1-weighted and proton-density-weighted turbo spin-echo (TSE) sequences, which typically reach acoustic noise levels up to 100 dB(A) in clinical practice. Five acoustic noise reduction strategies were combined: (1) gradient ramps and shapes were changed from trapezoidal to triangular, (2) variable-encoding-time imaging was implemented to relax the phase-encoding gradient timing, (3) RF pulses were adapted to avoid the need for reversing the polarity of the slice-rewinding gradient, (4) readout bandwidth was increased to provide more time for gradient activity on other axes, (5) the number of slices per TR was reduced to limit the total gradient activity per unit time. We evaluated the influence of each measure on the acoustic noise level, and conducted in vivo measurements on a healthy volunteer. Sound recordings were taken for comparison. An overall acoustic noise reduction of up to 16.8 dB(A) was obtained by the proposed strategies (1-4) and the acquisition of half the number of slices per TR only. Image quality in terms of SNR and CNR was found to be preserved. The proposed measures in this study allowed a threefold reduction in the acoustic perception of T 1-weighted and proton-density-weighted TSE sequences compared to a standard TSE-acquisition. This could be achieved without visible degradation of image quality, showing the potential to improve patient comfort and scan acceptability.

  1. Compressed Sensing Techniques Applied to Ultrasonic Imaging of Cargo Containers

    Directory of Open Access Journals (Sweden)

    Yuri Álvarez López

    2017-01-01

    Full Text Available One of the key issues in the fight against the smuggling of goods has been the development of scanners for cargo inspection. X-ray-based radiographic system scanners are the most developed sensing modality. However, they are costly and use bulky sources that emit hazardous, ionizing radiation. Aiming to improve the probability of threat detection, an ultrasonic-based technique, capable of detecting the footprint of metallic containers or compartments concealed within the metallic structure of the inspected cargo, has been proposed. The system consists of an array of acoustic transceivers that is attached to the metallic structure-under-inspection, creating a guided acoustic Lamb wave. Reflections due to discontinuities are detected in the images, provided by an imaging algorithm. Taking into consideration that the majority of those images are sparse, this contribution analyzes the application of Compressed Sensing (CS techniques in order to reduce the amount of measurements needed, thus achieving faster scanning, without compromising the detection capabilities of the system. A parametric study of the image quality, as a function of the samples needed in spatial and frequency domains, is presented, as well as the dependence on the sampling pattern. For this purpose, realistic cargo inspection scenarios have been simulated.

  2. Integral transformations applied to image encryption

    International Nuclear Information System (INIS)

    Vilardy, Juan M.; Torres, Cesar O.; Perez, Ronal

    2017-01-01

    In this paper we consider the application of the integral transformations for image encryption through optical systems, a mathematical algorithm under Matlab platform using fractional Fourier transform (FrFT) and Random Phase Mask (RPM) for digital images encryption is implemented. The FrFT can be related to others integral transforms, such as: Fourier transform, Sine and Cosine transforms, Radial Hilbert transform, fractional Sine transform, fractional Cosine transform, fractional Hartley transform, fractional Wavelet transform and Gyrator transform, among other transforms. The encryption scheme is based on the use of the FrFT, the joint transform correlator and two RPMs, which provide security and robustness to the implemented security system. One of the RPMs used during encryption-decryption and the fractional order of the FrFT are the keys to improve security and make the system more resistant against security attacks. (paper)

  3. Automated Quality Assurance Applied to Mammographic Imaging

    Directory of Open Access Journals (Sweden)

    Anne Davis

    2002-07-01

    Full Text Available Quality control in mammography is based upon subjective interpretation of the image quality of a test phantom. In order to suppress subjectivity due to the human observer, automated computer analysis of the Leeds TOR(MAM test phantom is investigated. Texture analysis via grey-level co-occurrence matrices is used to detect structures in the test object. Scoring of the substructures in the phantom is based on grey-level differences between regions and information from grey-level co-occurrence matrices. The results from scoring groups of particles within the phantom are presented.

  4. Acoustic imaging of vapor bubbles through optically non-transparent media

    International Nuclear Information System (INIS)

    Kolbe, W.F.; Turko, B.T.; Leskovar, B.

    1983-10-01

    A preliminary investigation of the feasibility of acoustic imaging of vapor bubbles through optically nontransparent media is described. Measurements are reported showing the echo signals produced by air filled glass spheres of various sizes positioned in an aqueous medium as well as signals produced by actual vapor bubbles within a water filled steel pipe. In addition, the influence of the metallic wall thickness and material on the amplitude of the echo signals is investigated. Finally several examples are given of the imaging of spherical bubbles within metallic pipes using a simulated array of acoustic transducers mounted circumferentially around the pipe. The measurement procedures and a description of the measuring system are also given

  5. Acoustical holographic recording with coherent optical read-out and image processing

    Science.gov (United States)

    Liu, H. K.

    1980-10-01

    New acoustic holographic wave memory devices have been designed for real-time in-situ recording applications. The basic operating principles of these devices and experimental results through the use of some of the prototypes of the devices are presented. Recording media used in the device include thermoplastic resin, Crisco vegetable oil, and Wilson corn oil. In addition, nonlinear coherent optical image processing techniques including equidensitometry, A-D conversion, and pseudo-color, all based on the new contact screen technique, are discussed with regard to the enhancement of the normally poor-resolved acoustical holographic images.

  6. Digital image processing applied Rock Art tracing

    Directory of Open Access Journals (Sweden)

    Montero Ruiz, Ignacio

    1998-06-01

    Full Text Available Adequate graphic recording has been one of the main objectives of rock art research. Photography has increased its role as a documentary technique. Now, digital image and its treatment allows new ways to observe the details of the figures and to develop a recording procedure which is as, or more, accurate than direct tracing. This technique also avoid deterioration of the rock paintings. The mathematical basis of this method is also presented.

    La correcta documentación del arte rupestre ha sido una preocupación constante por parte de los investigadores. En el desarrollo de nuevas técnicas de registro, directas e indirectas, la fotografía ha ido adquiriendo mayor protagonismo. La imagen digital y su tratamiento permiten nuevas posibilidades de observación de las figuras representadas y, en consecuencia, una lectura mediante la realización de calcos indirectos de tanta o mayor fiabilidad que la observación directa. Este sistema evita los riesgos de deterioro que provocan los calcos directos. Se incluyen las bases matemáticas que sustentan el método.

  7. On the focusing conditions in time-reversed acoustics, seismic interferometry, and Marchenko imaging

    NARCIS (Netherlands)

    Wapenaar, C.P.A.; Van der Neut, J.R.; Thorbecke, J.W.; Vasconcelos, I.; Van Manen, D.J.; Ravasi, M.

    2014-01-01

    Despite the close links between the fields of time-reversed acoustics, seismic interferometry and Marchenko imaging, a number of subtle differences exist. This paper reviews the various focusing conditions of these methods, the causality/acausality aspects of the corresponding focusing wavefields,

  8. Imaging of human tooth using ultrasound based chirp-coded nonlinear time reversal acoustics

    Czech Academy of Sciences Publication Activity Database

    Dos Santos, S.; Převorovský, Zdeněk

    2011-01-01

    Roč. 51, č. 6 (2011), s. 667-674 ISSN 0041-624X Institutional research plan: CEZ:AV0Z20760514 Keywords : TR-NEWS * chirp-coded excitation * echodentography * ultrasonic imaging Subject RIV: BI - Acoustics Impact factor: 1.838, year: 2011 http://www.sciencedirect.com/science/article/pii/S0041624X11000229

  9. A line array based near field imaging technique for characterising acoustical properties of elongated targets

    NARCIS (Netherlands)

    Driessen, F.P.G.

    1995-01-01

    With near field imaging techniques the acoustical pressure waves at distances other than the recorded can be calculated. Normally, acquisition on a two dimensional plane is necessary and extrapolation is performed by a Rayleigh integral. A near field single line instead of two dimensional plane

  10. Acoustic imaging of underground storage tank wastes: A feasibility study. Final report

    International Nuclear Information System (INIS)

    Turpening, R.; Zhu, Z.; Caravana, C.; Matarese, J.

    1995-01-01

    The objectives for this underground storage tank (UST) imaging investigation are: (1) to assess the feasibility of using acoustic methods in UST wastes, if shown to be feasible, develop and assess imaging strategies; (2) to assess the validity of using chemical simulants for the development of acoustic methods and equipment. This investigation examined the velocity of surrogates, both salt cake and sludge surrogates. In addition collected seismic cross well data in a real tank (114-TX) on the Hanford Reservation. Lastly, drawing on the knowledge of the simulants and the estimates of the velocities of the waste in tank 114-TX the authors generated a hypothetical model of waste in a tank and showed that non-linear travel time tomographic imaging would faithfully image that stratigraphy

  11. Smart DNA Fabrication Using Sound Waves: Applying Acoustic Dispensing Technologies to Synthetic Biology.

    Science.gov (United States)

    Kanigowska, Paulina; Shen, Yue; Zheng, Yijing; Rosser, Susan; Cai, Yizhi

    2016-02-01

    Acoustic droplet ejection (ADE) technology uses focused acoustic energy to transfer nanoliter-scale liquid droplets with high precision and accuracy. This noncontact, tipless, low-volume dispensing technology minimizes the possibility of cross-contamination and potentially reduces the costs of reagents and consumables. To date, acoustic dispensers have mainly been used in screening libraries of compounds. In this paper, we describe the first application of this powerful technology to the rapidly developing field of synthetic biology, for DNA synthesis and assembly at the nanoliter scale using a Labcyte Echo 550 acoustic dispenser. We were able to successfully downscale PCRs and the popular one-pot DNA assembly methods, Golden Gate and Gibson assemblies, from the microliter to the nanoliter scale with high assembly efficiency, which effectively cut the reagent cost by 20- to 100-fold. We envision that acoustic dispensing will become an instrumental technology in synthetic biology, in particular in the era of DNA foundries. © 2015 Society for Laboratory Automation and Screening.

  12. An Efficient Acoustic Density Estimation Method with Human Detectors Applied to Gibbons in Cambodia.

    Directory of Open Access Journals (Sweden)

    Darren Kidney

    Full Text Available Some animal species are hard to see but easy to hear. Standard visual methods for estimating population density for such species are often ineffective or inefficient, but methods based on passive acoustics show more promise. We develop spatially explicit capture-recapture (SECR methods for territorial vocalising species, in which humans act as an acoustic detector array. We use SECR and estimated bearing data from a single-occasion acoustic survey of a gibbon population in northeastern Cambodia to estimate the density of calling groups. The properties of the estimator are assessed using a simulation study, in which a variety of survey designs are also investigated. We then present a new form of the SECR likelihood for multi-occasion data which accounts for the stochastic availability of animals. In the context of gibbon surveys this allows model-based estimation of the proportion of groups that produce territorial vocalisations on a given day, thereby enabling the density of groups, instead of the density of calling groups, to be estimated. We illustrate the performance of this new estimator by simulation. We show that it is possible to estimate density reliably from human acoustic detections of visually cryptic species using SECR methods. For gibbon surveys we also show that incorporating observers' estimates of bearings to detected groups substantially improves estimator performance. Using the new form of the SECR likelihood we demonstrate that estimates of availability, in addition to population density and detection function parameters, can be obtained from multi-occasion data, and that the detection function parameters are not confounded with the availability parameter. This acoustic SECR method provides a means of obtaining reliable density estimates for territorial vocalising species. It is also efficient in terms of data requirements since since it only requires routine survey data. We anticipate that the low-tech field requirements will

  13. Schlieren imaging of the standing wave field in an ultrasonic acoustic levitator

    Science.gov (United States)

    Rendon, Pablo Luis; Boullosa, Ricardo R.; Echeverria, Carlos; Porta, David

    2015-11-01

    We consider a model of a single axis acoustic levitator consisting of two cylinders immersed in air and directed along the same axis. The first cylinder has a flat termination and functions as a sound emitter, and the second cylinder, which is simply a refector, has the side facing the first cylinder cut out by a spherical surface. By making the first cylinder vibrate at ultrasonic frequencies a standing wave is produced in the air between the cylinders which makes it possible, by means of the acoustic radiation pressure, to levitate one or several small objects of different shapes, such as spheres or disks. We use schlieren imaging to observe the acoustic field resulting from the levitation of one or several objects, and compare these results to previous numerical approximations of the field obtained using a finite element method. The authors acknowledge financial support from DGAPA-UNAM through project PAPIIT IN109214.

  14. Application of acoustical holography for construction shadow images in ultrasonic testing

    International Nuclear Information System (INIS)

    Kutzner, J.; Zimpfer, J.

    1977-01-01

    The full-scale, three-dimensional presentation of material defects by means of acoustical holography is limited on the one hand by an insufficient resolving power in depth of the procedure and, on the other hand, by the fact that the defects of the material to be examined often reflect mirror-like. Examined is the possible range of reducing these limitations by means of constructing shadow images of defects in ultrasonic testing without - as it is usually done - reconstructing the sonic field reflected by the flow but reconstructing the sonic field diffracted at the flow by means of acoustical holography. It has been shown that acoustical holography, during which the amplitude information is always analyzed as well as - on principle - the phase information, improves the efficiency of ultrasonic testing to a large extent. (orig.) [de

  15. Negative refraction imaging of solid acoustic waves by two-dimensional three-component phononic crystal

    International Nuclear Information System (INIS)

    Li Jing; Liu Zhengyou; Qiu Chunyin

    2008-01-01

    By using of the multiple scattering methods, we study the negative refraction imaging effect of solid acoustic waves by two-dimensional three-component phononic crystals composed of coated solid inclusions placed in solid matrix. We show that localized resonance mechanism brings on a group of flat single-mode bands in low-frequency region, which provides two equivalent frequency surfaces (EFS) close to circular. The two constant frequency surfaces correspond to two Bloch modes, a right-handed and a left-handed, whose leading mode are respectively transverse (T) and longitudinal (L) modes. The negative refraction behaviors of the two kinds of modes have been demonstrated by simulation of a Gaussian beam through a finite system. High-quality far-field imaging by a planar lens for transverse or longitudinal waves has been realized separately. This three-component phononic crystal may thus serve as a mode selector in negative refraction imaging of solid acoustic waves

  16. Methods And Systems For Using Reference Images In Acoustic Image Processing

    Science.gov (United States)

    Moore, Thomas L.; Barter, Robert Henry

    2005-01-04

    A method and system of examining tissue are provided in which a field, including at least a portion of the tissue and one or more registration fiducials, is insonified. Scattered acoustic information, including both transmitted and reflected waves, is received from the field. A representation of the field, including both the tissue and the registration fiducials, is then derived from the received acoustic radiation.

  17. Acoustic emission linear pulse holography

    Science.gov (United States)

    Collins, H.D.; Busse, L.J.; Lemon, D.K.

    1983-10-25

    This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

  18. Synthetic Aperture Sequential Beamformation applied to medical imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-01-01

    Synthetic Aperture Sequential Beamforming (SASB) is applied to medical ultrasound imaging using a multi element convex array transducer. The main motivation for SASB is to apply synthetic aperture techniques without the need for storing RF-data for a number of elements and hereby devise a system...... with a reduced system complexity. Using a 192 element, 3.5 MHz, λ-pitch transducer, it is demonstrated using tissue-phantom and wire-phantom measurements, how the speckle size and the detail resolution is improved compared to conventional imaging....

  19. Cellular automata codebooks applied to compact image compression

    Directory of Open Access Journals (Sweden)

    Radu DOGARU

    2006-12-01

    Full Text Available Emergent computation in semi-totalistic cellular automata (CA is used to generate a set of basis (or codebook. Such codebooks are convenient for simple and circuit efficient compression schemes based on binary vector quantization, applied to the bitplanes of any monochrome or color image. Encryption is also naturally included using these codebooks. Natural images would require less than 0.5 bits per pixel (bpp while the quality of the reconstructed images is comparable with traditional compression schemes. The proposed scheme is attractive for low power, sensor integrated applications.

  20. Demonstration of acoustic resonances in a cylindrical cavity applying the photoacoustic technique

    Science.gov (United States)

    Barreiro, N. L.; Vallespi, A. S.; Zajarevich, N. M.; Peuriot, A. L.; Slezak, V. B.

    2017-09-01

    In this work we present some experiments which can be performed in college or on the first courses of university to acquire knowledge about resonant acoustical phenomena in closed cavities in a tangible way, through experiments based on the photoacoustic effect in gases. This phenomenon consists in the generation of acoustic waves after optical excitation of an absorbing gas and further local heating of the non-absorbing surrounding gas by energy exchange through collisions between molecules of both species. Simple experiments, performed with daily live elements, can be very useful for teachers and students to get in touch with the phenomenon of acoustic resonances with the addition of concepts about light-matter interaction. The setups consist of the resonant cavity, the illumination source and the signal detection-acquisition scheme. In this paper a closed glass test tube is used as the resonant cavity and is filled with a mixture of nitrogen dioxide and air. The illumination is performed by a pulsed power LED modulated at different resonant frequencies of the cavity. A microphone inside the tube is connected to an oscilloscope which displays the photoacoustic signal. The LED is moved along the tube showing how different resonant modes can be excited.

  1. Applying Acoustical and Musicological Analysis to Detect Brain Responses to Realistic Music: A Case Study

    Directory of Open Access Journals (Sweden)

    Niels Trusbak Haumann

    2018-05-01

    Full Text Available Music information retrieval (MIR methods offer interesting possibilities for automatically identifying time points in music recordings that relate to specific brain responses. However, how the acoustical features and the novelty of the music structure affect the brain response is not yet clear. In the present study, we tested a new method for automatically identifying time points of brain responses based on MIR analysis. We utilized an existing database including brain recordings of 48 healthy listeners measured with electroencephalography (EEG and magnetoencephalography (MEG. While we succeeded in capturing brain responses related to acoustical changes in the modern tango piece Adios Nonino, we obtained less reliable brain responses with a metal rock piece and a modern symphony orchestra musical composition. However, brain responses might also relate to the novelty of the music structure. Hence, we added a manual musicological analysis of novelty in the musical structure to the computational acoustic analysis, obtaining strong brain responses even to the rock and modern pieces. Although no standardized method yet exists, these preliminary results suggest that analysis of novelty in music is an important aid to MIR analysis for investigating brain responses to realistic music.

  2. High-resolution acoustic imaging at low frequencies using 3D-printed metamaterials

    Directory of Open Access Journals (Sweden)

    S. Laureti

    2016-12-01

    Full Text Available An acoustic metamaterial has been constructed using 3D printing. It contained an array of air-filled channels, whose size and shape could be varied within the design and manufacture process. In this paper we analyze both numerically and experimentally the properties of this polymer metamaterial structure, and demonstrate its use for the imaging of a sample with sub-wavelength dimensions in the audible frequency range.

  3. Underwater Acoustic Matched Field Imaging Based on Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Huichen Yan

    2015-10-01

    Full Text Available Matched field processing (MFP is an effective method for underwater target imaging and localizing, but its performance is not guaranteed due to the nonuniqueness and instability problems caused by the underdetermined essence of MFP. By exploiting the sparsity of the targets in an imaging area, this paper proposes a compressive sensing MFP (CS-MFP model from wave propagation theory by using randomly deployed sensors. In addition, the model’s recovery performance is investigated by exploring the lower bounds of the coherence parameter of the CS dictionary. Furthermore, this paper analyzes the robustness of CS-MFP with respect to the displacement of the sensors. Subsequently, a coherence-excluding coherence optimized orthogonal matching pursuit (CCOOMP algorithm is proposed to overcome the high coherent dictionary problem in special cases. Finally, some numerical experiments are provided to demonstrate the effectiveness of the proposed CS-MFP method.

  4. Understanding Acoustic Cavitation Initiation by Porous Nanoparticles: Toward Nanoscale Agents for Ultrasound Imaging and Therapy.

    Science.gov (United States)

    Yildirim, Adem; Chattaraj, Rajarshi; Blum, Nicholas T; Goodwin, Andrew P

    2016-08-23

    Ultrasound is widely applied in medical diagnosis and therapy due to its safety, high penetration depth, and low cost. In order to improve the contrast of sonographs and efficiency of the ultrasound therapy, echogenic gas bodies or droplets (with diameters from 200 nm to 10 µm) are often used, which are not very stable in the bloodstream and unable to penetrate into target tissues. Recently, it was demonstrated that nanobubbles stabilized by nanoparticles can nucleate ultrasound responsive microbubbles under reduced acoustic pressures, which is very promising for the development of nanoscale (ultrasound agents. However, there is still very little understanding about the effects of nanoparticle properties on the stabilization of nanobubbles and nucleation of acoustic cavitation by these nanobubbles. Here, a series of mesoporous silica nanoparticles with sizes around 100 nm but with different morphologies were synthesized to understand the effects of nanoparticle porosity, surface roughness, hydrophobicity, and hydrophilic surface modification on acoustic cavitation inception by porous nanoparticles. The chemical analyses of the nanoparticles showed that, while the nanoparticles were prepared using the same silica precursor (TEOS) and surfactant (CTAB), they revealed varying amounts of carbon impurities, hydroxyl content, and degrees of silica crosslinking. Carbon impurities or hydrophobic modification with methyl groups is found to be essential for nanobubble stabilization by mesoporous silica nanoparticles. The acoustic cavitation experiments in the presence of ethanol and/or bovine serum albumin (BSA) demonstrated that acoustic cavitation is predominantly nucleated by the nanobubbles stabilized at the nanoparticle surface not inside the mesopores. Finally, acoustic cavitation experiments with rough and smooth nanoparticles were suggested that a rough nanoparticle surface is needed to largely preserve surface nanobubbles after coating the surface with hydrophilic

  5. A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

    Science.gov (United States)

    Zourmand, Alireza; Mirhassani, Seyed Mostafa; Ting, Hua-Nong; Bux, Shaik Ismail; Ng, Kwan Hoong; Bilgen, Mehmet; Jalaludin, Mohd Amin

    2014-07-25

    The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

  6. Digital processing methodology applied to exploring of radiological images

    International Nuclear Information System (INIS)

    Oliveira, Cristiane de Queiroz

    2004-01-01

    In this work, digital image processing is applied as a automatic computational method, aimed for exploring of radiological images. It was developed an automatic routine, from the segmentation and post-processing techniques to the radiology images acquired from an arrangement, consisting of a X-ray tube, target and filter of molybdenum, of 0.4 mm and 0.03 mm, respectively, and CCD detector. The efficiency of the methodology developed is showed in this work, through a case study, where internal injuries in mangoes are automatically detected and monitored. This methodology is a possible tool to be introduced in the post-harvest process in packing houses. A dichotomic test was applied to evaluate a efficiency of the method. The results show a success of 87.7% to correct diagnosis and 12.3% to failures to correct diagnosis with a sensibility of 93% and specificity of 80%. (author)

  7. Acoustically modulated magnetic resonance imaging of gas-filled protein nanostructures

    Science.gov (United States)

    Lu, George J.; Farhadi, Arash; Szablowski, Jerzy O.; Lee-Gosselin, Audrey; Barnes, Samuel R.; Lakshmanan, Anupama; Bourdeau, Raymond W.; Shapiro, Mikhail G.

    2018-05-01

    Non-invasive biological imaging requires materials capable of interacting with deeply penetrant forms of energy such as magnetic fields and sound waves. Here, we show that gas vesicles (GVs), a unique class of gas-filled protein nanostructures with differential magnetic susceptibility relative to water, can produce robust contrast in magnetic resonance imaging (MRI) at sub-nanomolar concentrations, and that this contrast can be inactivated with ultrasound in situ to enable background-free imaging. We demonstrate this capability in vitro, in cells expressing these nanostructures as genetically encoded reporters, and in three model in vivo scenarios. Genetic variants of GVs, differing in their magnetic or mechanical phenotypes, allow multiplexed imaging using parametric MRI and differential acoustic sensitivity. Additionally, clustering-induced changes in MRI contrast enable the design of dynamic molecular sensors. By coupling the complementary physics of MRI and ultrasound, this nanomaterial gives rise to a distinct modality for molecular imaging with unique advantages and capabilities.

  8. Heavy-Ion <span class="hlt">Imaging</span> <span class="hlt">Applied</span> To Medicine

    Energy Technology Data Exchange (ETDEWEB)

    Fabrikant, J. I.; Tobias, C. A.; Capp, M. P.; Benton, E. V.; Holley, W. R.; Gray, Joel E.; Hendee, William R.; Haus, Andrew G.; Properzio, William S.

    1980-08-18

    Heavy particle radiography is a newly developed noninvasive low dose imaging procedure with increased resolution of minute density differences in soft tissues of the body. The method utilizes accelerated high energy ions, primarily carbon and neon, at the BEVALAC accelerator at the Lawrence Berkeley Laboratory. The research program applied to medicine utilizes heavy-ion radiography for low dose mammography, for treatment planning for cancer patients, and for imaging and accurate densitometry of skeletal structures and brain and spinal neoplasms. The presentation will be illustrated with clinical cases under study. Discussion will include the potential of heavy-ion imaging, and particularly reconstruction tomography, as an adjunct to existing diagnostic imaging procedures in medicine, both for the applications to the diagnosis, management and treatment of clinical cancer in man, but also for the early detection of small soft tissue tumors at low radiation dose.

  9. Estimation of fracture roughness from the acoustic borehole televiewer image

    International Nuclear Information System (INIS)

    Bae, Dae Soek; Kim, Chun Soo; Kim, Kyung Soo; Park, Byung Yoon; Koh, Yong Kweon

    2000-12-01

    Estimation of fracture roughness - as one of the basic hydraulic fracture parameters - is very important in assessing ground water flow described by using discrete fracture network modeling. Former manual estimation of the roughness for each fracture surface of drill cores is above all a tedious, time-consuming work and will often cause some ambiguities of roughness interpretation partly due to the subjective judgements of observers, and partly due to the measuring procedure itself. However, recently, indebt to the highly reliable Televiewer data for the fracture discrimination, it has led to a guess to develop a relationship between the traditional roughness method based on a linear profiles and the method from the Televiewer image based on a ellipsoidal profile. Hence, the aim of this work is to develop an automatic evaluation algorithm for measuring the roughness from the Televiewer images. A highly reliable software named 'FRAFA' has been developed and realized to the extent that its utility merits. In the developing procedure, various problems - such as the examination of a new base line(ellipsoidal) for measuring the unevenness of fracture, the elimination of overlapping fracture signatures or noise, the wavelet estimation according to the type of fractures and the digitalization of roughness etc. - were considered. With these consideration in mind, the newly devised algorithm for the estimation of roughness curves showed a great potential not only for avoiding ambiguities of roughness interpretation but also for the judgement of roughness classification

  10. Applying acoustic telemetry to understand contaminant exposure and bioaccumulation patterns in mobile fishes.

    Science.gov (United States)

    Taylor, Matthew D; van der Meulen, Dylan E; Brodie, Stephanie; Cadiou, Gwenaël; Knott, Nathan A

    2018-06-01

    Contamination in urbanised estuaries presents a risk to human health, and to the viability of populations of exploited species. Assessing animal movements in relation to contaminated areas may help to explain patterns in bioaccumulation, and assist in the effective management of health risks associated with consumption of exploited species. Using polychlorinated dibenzodioxin and polychlorinated dibenzofuran (PCDD/Fs) contamination in Sydney Harbour estuary as a case study, we present a study that links movement patterns resolved using acoustic telemetry to the accumulation of contaminants in mobile fish on a multi-species basis. Fifty-four individuals across six exploited species (Sea Mullet Mugil cephalus; Luderick Girella tricuspidata; Yellowfin Bream Acanthopagrus australis; Silver Trevally Pseudocaranx georgianus; Mulloway Argyrosomus japonicus; Yellowtail Kingfish Seriola lalandi) were tagged with acoustic transmitters, and their movements tracked for up to 3years. There was substantial inter-specific variation in fish distribution along the estuary. The proportion of distribution that overlapped with contaminated areas explained 84-98% of the inter-specific variation in lipid-standardised biota PCDD/F concentration. There was some seasonal variation in distribution along the estuary, but movement patterns indicated that Sea Mullet, Yellowfin Bream, Silver Trevally, and Mulloway were likely to be exposed to contaminated areas during the period of gonadal maturation. Acoustic telemetry allows examination of spatial and temporal patterns in exposure to contamination. When used alongside biota sampling and testing, this offers a powerful approach to assess exposure, bioaccumulation, and potential risks faced by different species, as well as human health risks associated with their consumption. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  11. Advanced methods for image registration applied to JET videos

    Energy Technology Data Exchange (ETDEWEB)

    Craciunescu, Teddy, E-mail: teddy.craciunescu@jet.uk [EURATOM-MEdC Association, NILPRP, Bucharest (Romania); Murari, Andrea [Consorzio RFX, Associazione EURATOM-ENEA per la Fusione, Padova (Italy); Gelfusa, Michela [Associazione EURATOM-ENEA – University of Rome “Tor Vergata”, Roma (Italy); Tiseanu, Ion; Zoita, Vasile [EURATOM-MEdC Association, NILPRP, Bucharest (Romania); Arnoux, Gilles [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon (United Kingdom)

    2015-10-15

    Graphical abstract: - Highlights: • Development of an image registration method for JET IR and fast visible cameras. • Method based on SIFT descriptors and coherent point drift points set registration technique. • Method able to deal with extremely noisy images and very low luminosity images. • Computation time compatible with the inter-shot analysis. - Abstract: The last years have witnessed a significant increase in the use of digital cameras on JET. They are routinely applied for imaging in the IR and visible spectral regions. One of the main technical difficulties in interpreting the data of camera based diagnostics is the presence of movements of the field of view. Small movements occur due to machine shaking during normal pulses while large ones may arise during disruptions. Some cameras show a correlation of image movement with change of magnetic field strength. For deriving unaltered information from the videos and for allowing correct interpretation an image registration method, based on highly distinctive scale invariant feature transform (SIFT) descriptors and on the coherent point drift (CPD) points set registration technique, has been developed. The algorithm incorporates a complex procedure for rejecting outliers. The method has been applied for vibrations correction to videos collected by the JET wide angle infrared camera and for the correction of spurious rotations in the case of the JET fast visible camera (which is equipped with an image intensifier). The method has proved to be able to deal with the images provided by this camera frequently characterized by low contrast and a high level of blurring and noise.

  12. Polymer Optical Fibre Sensors for Endoscopic Opto-Acoustic Imaging

    DEFF Research Database (Denmark)

    Broadway, Christian; Gallego, Daniel; Woyessa, Getinet

    2015-01-01

    in existing publications. A great advantage can be obtained for endoscopy due to a small size and array potential to provide discrete imaging speed improvements. Optical fibre exhibits numerous advantages over conventional piezo-electric transducers, such as immunity from electromagnetic interference...... is the physical size of the device, allowing compatibility with current technology, while governing flexibility of the distal end of the endoscope based on the needs of the sensor. Polymer optical fibre (POF) presents a novel approach for endoscopic applications and has been positively discussed and compared...... and a higher resolution at small sizes. Furthermore, micro structured polymer optical fibres offer over 12 times the sensitivity of silica fibre. We present a polymer fibre Bragg grating ultrasound detector with a core diameter of 125 microns. We discuss the ultrasonic signals received and draw conclusions...

  13. Perceptual thresholds for detecting modifications applied to the acoustical properties of a violin.

    Science.gov (United States)

    Fritz, Claudia; Cross, Ian; Moore, Brian C J; Woodhouse, Jim

    2007-12-01

    This study is the first step in the psychoacoustic exploration of perceptual differences between the sounds of different violins. A method was used which enabled the same performance to be replayed on different "virtual violins," so that the relationships between acoustical characteristics of violins and perceived qualities could be explored. Recordings of real performances were made using a bridge-mounted force transducer, giving an accurate representation of the signal from the violin string. These were then played through filters corresponding to the admittance curves of different violins. Initially, limits of listener performance in detecting changes in acoustical characteristics were characterized. These consisted of shifts in frequency or increases in amplitude of single modes or frequency bands that have been proposed previously to be significant in the perception of violin sound quality. Thresholds were significantly lower for musically trained than for nontrained subjects but were not significantly affected by the violin used as a baseline. Thresholds for the musicians typically ranged from 3 to 6 dB for amplitude changes and 1.5%-20% for frequency changes. Interpretation of the results using excitation patterns showed that thresholds for the best subjects were quite well predicted by a multichannel model based on optimal processing.

  14. Acoustic Imaging of a Turbidity Current Flowing along a Channel

    Science.gov (United States)

    Hughes Clarke, J. E.; Hiroji, A.; Cahill, L.; Fedele, J. J.

    2017-12-01

    As part of a 3 month sequence of repetitive surveys and ADCP monitoring, more than 30 turbidity currents have been identified modifying a lobe channel in 130 to 190m of water on the Squamish prodelta. For a 6 day period, daily surveys at low tide tried to capture the change resulting from a single flow. On the 8thof June three flows occurred within a half hour. Along channel multibeam images of the seabed and water column were obtained from a moving vessel immediately before, during and after the passage of the third flow. In this manner the spatial extent of the in-channel and overbank flow could be constrained. By following the flow, the spatial pattern of scattering from the flow upper surface could be examined over a 2 km length of the channel. Along channel bands of high scattering appear related to enhanced release of gas along the channel flanks. Notably, no signature of the underlying across-channel bedform modulations were evident, suggesting that the upper surface of the flow does not feel the influence of the channel floor. Overbank spillage of the flow could be detected by perturbation of a plankton scattering layer just above the seabed. Additionally, evidence of enhanced overbank deposition due to flow stripping on the outer corner of a bend was identified from backscatter changes. The specific seabed alteration due to this flow could be identified and compared with the cumulative change over three months in the channel and adjacent channel-lobe transition zone. As the flow passed under the ADCP, it had a peak velocity of over 2 m/s, a thickness of 4-5m and duration of 35 minutes. Based on the timing of the flow head when in view of the surface vessel, it was decelerating as it exited the mouth of the channel.

  15. Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

    OpenAIRE

    Ben Minnaert; Nobby Stevens

    2017-01-01

    Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this opti...

  16. Iterative electromagnetic Born inversion applied to earth conductivity imaging

    Science.gov (United States)

    Alumbaugh, D. L.

    1993-08-01

    This thesis investigates the use of a fast imaging technique to deduce the spatial conductivity distribution in the earth from low frequency (less than 1 MHz), cross well electromagnetic (EM) measurements. The theory embodied in this work is the extension of previous strategies and is based on the Born series approximation to solve both the forward and inverse problem. Nonlinear integral equations are employed to derive the series expansion which accounts for the scattered magnetic fields that are generated by inhomogeneities embedded in either a homogenous or a layered earth. A sinusoidally oscillating, vertically oriented magnetic dipole is employed as a source, and it is assumed that the scattering bodies are azimuthally symmetric about the source dipole axis. The use of this model geometry reduces the 3-D vector problem to a more manageable 2-D scalar form. The validity of the cross well EM method is tested by applying the imaging scheme to two sets of field data. Images of the data collected at the Devine, Texas test site show excellent correlation with the well logs. Unfortunately there is a drift error present in the data that limits the accuracy of the results. A more complete set of data collected at the Richmond field station in Richmond, California demonstrates that cross well EM can be successfully employed to monitor the position of an injected mass of salt water. Both the data and the resulting images clearly indicate the plume migrates toward the north-northwest. The plausibility of these conclusions is verified by applying the imaging code to synthetic data generated by a 3-D sheet model.

  17. Scanning electron-acoustic imaging of residual stress distributions in aluminum metal and ZrSiO4 multiphase ceramics

    International Nuclear Information System (INIS)

    Zhang, B.Y.; Jiang, F.M.; Shi, Y.; Yin, Q.R.; Qian, M.L.

    1997-01-01

    The scanning electron-acoustic imaging technique has been used in the characterization of the residual stress field distributions existing in the subsurface in aluminum disks and 20 vol% SiC ( w)/ZrSiO 4 multiphase ceramics left by Vicker close-quote s indentation. The experimental results reveal that the distribution areas are the plastic-elastic interchange zones. The electron-acoustic signal generation mechanism in the samples are discussed. copyright 1997 American Institute of Physics

  18. Development and validation of a combined phased acoustical radiosity and image source model for predicting sound fields in rooms

    DEFF Research Database (Denmark)

    Marbjerg, Gerd Høy; Brunskog, Jonas; Jeong, Cheol-Ho

    2015-01-01

    A model, combining acoustical radiosity and the image source method, including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Method (PARISM), and it has been developed in order to be able to model both specular and diffuse...... radiosity by regarding the model as being stochastic. Three methods of implementation are proposed and investigated, and finally, recommendations are made for their use. Validation of the image source method is done by comparison with finite element simulations of a rectangular room with a porous absorber...

  19. Time domain localization technique with sparsity constraint for imaging acoustic sources

    Science.gov (United States)

    Padois, Thomas; Doutres, Olivier; Sgard, Franck; Berry, Alain

    2017-09-01

    This paper addresses source localization technique in time domain for broadband acoustic sources. The objective is to accurately and quickly detect the position and amplitude of noise sources in workplaces in order to propose adequate noise control options and prevent workers hearing loss or safety risk. First, the generalized cross correlation associated with a spherical microphone array is used to generate an initial noise source map. Then a linear inverse problem is defined to improve this initial map. Commonly, the linear inverse problem is solved with an l2 -regularization. In this study, two sparsity constraints are used to solve the inverse problem, the orthogonal matching pursuit and the truncated Newton interior-point method. Synthetic data are used to highlight the performances of the technique. High resolution imaging is achieved for various acoustic sources configurations. Moreover, the amplitudes of the acoustic sources are correctly estimated. A comparison of computation times shows that the technique is compatible with quasi real-time generation of noise source maps. Finally, the technique is tested with real data.

  20. Acoustical holographic Siamese image technique for imaging radial cracks in reactor piping

    International Nuclear Information System (INIS)

    Collins, H.D.; Gribble, R.P.

    1985-04-01

    This paper describes a unique technique (i.e., ''Siamese imaging'') for imaging quasi-vertical defects in reactor pipe weldments. The Siamese image is a bi-symmetrical view of the inner surface defect. Image construction geometry consists of two probes (i.e., source/receiver) operating either from opposite sides or the same side of the defect to be imaged. As the probes are scanned across a lower surface connected defect, they encounter two images - first the normal upright image and then the inverted image. The final integrated image consists of two images connected along their baselines, thus we call it a ''Siamese image.'' The experimental imaging results on simulated and natural cracks in reactor piping weldments graphically illustrate this unique technique. Excellent images of mechanical fatique and thermal cracks were obtained on ferritic and austenitic piping

  1. The Use of Acoustic Radiation Force Decorrelation-Weighted Pulse Inversion for Enhanced Ultrasound Contrast Imaging.

    Science.gov (United States)

    Herbst, Elizabeth B; Unnikrishnan, Sunil; Wang, Shiying; Klibanov, Alexander L; Hossack, John A; Mauldin, Frank William

    2017-02-01

    The use of ultrasound imaging for cancer diagnosis and screening can be enhanced with the use of molecularly targeted microbubbles. Nonlinear imaging strategies such as pulse inversion (PI) and "contrast pulse sequences" (CPS) can be used to differentiate microbubble signal, but often fail to suppress highly echogenic tissue interfaces. This failure results in false-positive detection and potential misdiagnosis. In this study, a novel acoustic radiation force (ARF)-based approach was developed for superior microbubble signal detection. The feasibility of this technique, termed ARF decorrelation-weighted PI (ADW-PI), was demonstrated in vivo using a subcutaneous mouse tumor model. Tumors were implanted in the hindlimb of C57BL/6 mice by subcutaneous injection of MC38 cells. Lipid-shelled microbubbles were conjugated to anti-VEGFR2 antibody and administered via bolus injection. An image sequence using ARF pulses to generate microbubble motion was combined with PI imaging on a Verasonics Vantage programmable scanner. ADW-PI images were generated by combining PI images with interframe signal decorrelation data. For comparison, CPS images of the same mouse tumor were acquired using a Siemens Sequoia clinical scanner. Microbubble-bound regions in the tumor interior exhibited significantly higher signal decorrelation than static tissue (n = 9, P < 0.001). The application of ARF significantly increased microbubble signal decorrelation (n = 9, P < 0.01). Using these decorrelation measurements, ADW-PI imaging demonstrated significantly improved microbubble contrast-to-tissue ratio when compared with corresponding CPS or PI images (n = 9, P < 0.001). Contrast-to-tissue ratio improved with ADW-PI by approximately 3 dB compared with PI images and 2 dB compared with CPS images. Acoustic radiation force can be used to generate adherent microbubble signal decorrelation without microbubble bursting. When combined with PI, measurements of the resulting microbubble signal

  2. Reconstruction of an acoustic pressure field in a resonance tube by particle image velocimetry.

    Science.gov (United States)

    Kuzuu, K; Hasegawa, S

    2015-11-01

    A technique for estimating an acoustic field in a resonance tube is suggested. The estimation of an acoustic field in a resonance tube is important for the development of the thermoacoustic engine, and can be conducted employing two sensors to measure pressure. While this measurement technique is known as the two-sensor method, care needs to be taken with the location of pressure sensors when conducting pressure measurements. In the present study, particle image velocimetry (PIV) is employed instead of a pressure measurement by a sensor, and two-dimensional velocity vector images are extracted as sequential data from only a one- time recording made by a video camera of PIV. The spatial velocity amplitude is obtained from those images, and a pressure distribution is calculated from velocity amplitudes at two points by extending the equations derived for the two-sensor method. By means of this method, problems relating to the locations and calibrations of multiple pressure sensors are avoided. Furthermore, to verify the accuracy of the present method, the experiments are conducted employing the conventional two-sensor method and laser Doppler velocimetry (LDV). Then, results by the proposed method are compared with those obtained with the two-sensor method and LDV.

  3. Acoustic Emission and Echo Signal Compensation Techniques Applied to an Ultrasonic Logging-While-Drilling Caliper.

    Science.gov (United States)

    Yao, Yongchao; Ju, Xiaodong; Lu, Junqiang; Men, Baiyong

    2017-06-10

    A logging-while-drilling (LWD) caliper is a tool used for the real-time measurement of a borehole diameter in oil drilling engineering. This study introduces the mechanical structure and working principle of a new LWD caliper based on ultrasonic distance measurement (UDM). The detection range is a major performance index of a UDM system. This index is determined by the blind zone length and remote reflecting interface detection capability of the system. To reduce the blind zone length and detect near the reflecting interface, a full bridge acoustic emission technique based on bootstrap gate driver (BGD) and metal-oxide-semiconductor field effect transistor (MOSFET) is designed by analyzing the working principle and impedance characteristics of a given piezoelectric transducer. To detect the remote reflecting interface and reduce the dynamic range of the received echo signals, the relationships between the echo amplitude and propagation distance of ultrasonic waves are determined. A signal compensation technique based on time-varying amplification theory, which can automatically change the gain according to the echo arrival time is designed. Lastly, the aforementioned techniques and corresponding circuits are experimentally verified. Results show that the blind zone length in the UDM system of the LWD caliper is significantly reduced and the capability to detect the remote reflecting interface is considerably improved.

  4. Acoustic Emission and Echo Signal Compensation Techniques Applied to an Ultrasonic Logging-While-Drilling Caliper

    Directory of Open Access Journals (Sweden)

    Yongchao Yao

    2017-06-01

    Full Text Available A logging-while-drilling (LWD caliper is a tool used for the real-time measurement of a borehole diameter in oil drilling engineering. This study introduces the mechanical structure and working principle of a new LWD caliper based on ultrasonic distance measurement (UDM. The detection range is a major performance index of a UDM system. This index is determined by the blind zone length and remote reflecting interface detection capability of the system. To reduce the blind zone length and detect near the reflecting interface, a full bridge acoustic emission technique based on bootstrap gate driver (BGD and metal-oxide-semiconductor field effect transistor (MOSFET is designed by analyzing the working principle and impedance characteristics of a given piezoelectric transducer. To detect the remote reflecting interface and reduce the dynamic range of the received echo signals, the relationships between the echo amplitude and propagation distance of ultrasonic waves are determined. A signal compensation technique based on time-varying amplification theory, which can automatically change the gain according to the echo arrival time is designed. Lastly, the aforementioned techniques and corresponding circuits are experimentally verified. Results show that the blind zone length in the UDM system of the LWD caliper is significantly reduced and the capability to detect the remote reflecting interface is considerably improved.

  5. Electromagnetic Acoustic Transducers Applied to High Temperature Plates for Potential Use in the Solar Thermal Industry

    Directory of Open Access Journals (Sweden)

    Maria Kogia

    2015-12-01

    Full Text Available Concentrated Solar Plants (CSPs are used in solar thermal industry for collecting and converting sunlight into electricity. Parabolic trough CSPs are the most widely used type of CSP and an absorber tube is an essential part of them. The hostile operating environment of the absorber tubes, such as high temperatures (400–550 °C, contraction/expansion, and vibrations, may lead them to suffer from creep, thermo-mechanical fatigue, and hot corrosion. Hence, their condition monitoring is of crucial importance and a very challenging task as well. Electromagnetic Acoustic Transducers (EMATs are a promising, non-contact technology of transducers that has the potential to be used for the inspection of large structures at high temperatures by exciting Guided Waves. In this paper, a study regarding the potential use of EMATs in this application and their performance at high temperature is presented. A Periodic Permanent Magnet (PPM EMAT with a racetrack coil, designed to excite Shear Horizontal waves (SH0, has been theoretically and experimentally evaluated at both room and high temperatures.

  6. Delamination of plasters applied to historical masonry walls: analysis by acoustic emission technique and numerical model

    Science.gov (United States)

    Grazzini, A.; Lacidogna, G.; Valente, S.; Accornero, F.

    2018-06-01

    Masonry walls of historical buildings are subject to rising damp effects due to capillary or rain infiltrations, which in the time produce decay and delamination of historical plasters. In the restoration of masonry buildings, the plaster detachment frequently occurs because of mechanical incompatibility in repair mortar. An innovative laboratory procedure is described for test mechanical adhesion of new repair mortars. Compression static tests were carried out on composite specimens stone block-repair mortar, which specific geometry can test the de-bonding process of mortar in adherence with a stone masonry structure. The acoustic emission (AE) technique was employed for estimating the amount of energy released from fracture propagation in adherence surface between mortar and stone. A numerical simulation was elaborated based on the cohesive crack model. The evolution of detachment process of mortar in a coupled stone brick-mortar system was analysed by triangulation of AE signals, which can improve the numerical model and predict the type of failure in the adhesion surface of repair plaster. Through the cohesive crack model, it was possible to interpret theoretically the de-bonding phenomena occurring at the interface between stone block and mortar. Therefore, the mechanical behaviour of the interface is characterized.

  7. Super-resolution imaging applied to moving object tracking

    Science.gov (United States)

    Swalaganata, Galandaru; Ratna Sulistyaningrum, Dwi; Setiyono, Budi

    2017-10-01

    Moving object tracking in a video is a method used to detect and analyze changes that occur in an object that being observed. Visual quality and the precision of the tracked target are highly wished in modern tracking system. The fact that the tracked object does not always seem clear causes the tracking result less precise. The reasons are low quality video, system noise, small object, and other factors. In order to improve the precision of the tracked object especially for small object, we propose a two step solution that integrates a super-resolution technique into tracking approach. First step is super-resolution imaging applied into frame sequences. This step was done by cropping the frame in several frame or all of frame. Second step is tracking the result of super-resolution images. Super-resolution image is a technique to obtain high-resolution images from low-resolution images. In this research single frame super-resolution technique is proposed for tracking approach. Single frame super-resolution was a kind of super-resolution that it has the advantage of fast computation time. The method used for tracking is Camshift. The advantages of Camshift was simple calculation based on HSV color that use its histogram for some condition and color of the object varies. The computational complexity and large memory requirements required for the implementation of super-resolution and tracking were reduced and the precision of the tracked target was good. Experiment showed that integrate a super-resolution imaging into tracking technique can track the object precisely with various background, shape changes of the object, and in a good light conditions.

  8. Acoustic noise in functional magnetic resonance imaging reduces pain unpleasantness ratings.

    Science.gov (United States)

    Boyle, Y; Bentley, D E; Watson, A; Jones, A K P

    2006-07-01

    Functional magnetic resonance imaging (fMRI) is increasingly used in cognitive studies. Unfortunately, the scanner produces acoustic noise during the image acquisition process. Interference from acoustic noise is known to affect auditory, visual and motor processing, raising the possibility that acoustic interference may also modulate processing of other sensory modalities such as pain. With the increasing use of fMRI in the investigation of the mechanisms of pain perception, particularly in relation to attention, this issue has become highly relevant. Pain is a complex experience, composed of sensory-discriminative, affective-motivational and cognitive-evaluative components. The aim of this experiment was to assess the effect of MRI scanner noise, compared to white noise, on the affective (unpleasantness) and the sensory-discriminative (localisation) components of pain. Painful radiant heat from a CO(2) laser was delivered to the skin of the right forearm in 24 healthy volunteers. The volunteers attended to either pain location or pain unpleasantness during three conditions: i) no noise, ii) exposure to MRI scanner noise (85 dB) or iii) exposure to white noise (85 dB). Both MRI scanner noise and white noise significantly reduced unpleasantness ratings (from 5.1 +/- 1.6 in the control condition to 4.7 +/- 1.5 (P = 0.002) and 4.6 +/- 1.6 (P white noise respectively), whereas the ability to localise pain was not significantly affected (from 85.4 +/- 9.2% correct in the control condition to 83.1 +/- 10.3% (P = 0.06) and 83.9 +/- 9.5% (P = 0.27) with MRI scanner and white noise respectively). This phenomenon should be taken into account in the design of fMRI studies into human pain perception.

  9. Hyperspectral imaging applied to complex particulate solids systems

    Science.gov (United States)

    Bonifazi, Giuseppe; Serranti, Silvia

    2008-04-01

    HyperSpectral Imaging (HSI) is based on the utilization of an integrated hardware and software (HW&SW) platform embedding conventional imaging and spectroscopy to attain both spatial and spectral information from an object. Although HSI was originally developed for remote sensing, it has recently emerged as a powerful process analytical tool, for non-destructive analysis, in many research and industrial sectors. The possibility to apply on-line HSI based techniques in order to identify and quantify specific particulate solid systems characteristics is presented and critically evaluated. The originally developed HSI based logics can be profitably applied in order to develop fast, reliable and lowcost strategies for: i) quality control of particulate products that must comply with specific chemical, physical and biological constraints, ii) performance evaluation of manufacturing strategies related to processing chains and/or realtime tuning of operative variables and iii) classification-sorting actions addressed to recognize and separate different particulate solid products. Case studies, related to recent advances in the application of HSI to different industrial sectors, as agriculture, food, pharmaceuticals, solid waste handling and recycling, etc. and addressed to specific goals as contaminant detection, defect identification, constituent analysis and quality evaluation are described, according to authors' originally developed application.

  10. Wavelet Domain Radiofrequency Pulse Design Applied to Magnetic Resonance Imaging.

    Directory of Open Access Journals (Sweden)

    Andrew M Huettner

    Full Text Available A new method for designing radiofrequency (RF pulses with numerical optimization in the wavelet domain is presented. Numerical optimization may yield solutions that might otherwise have not been discovered with analytic techniques alone. Further, processing in the wavelet domain reduces the number of unknowns through compression properties inherent in wavelet transforms, providing a more tractable optimization problem. This algorithm is demonstrated with simultaneous multi-slice (SMS spin echo refocusing pulses because reduced peak RF power is necessary for SMS diffusion imaging with high acceleration factors. An iterative, nonlinear, constrained numerical minimization algorithm was developed to generate an optimized RF pulse waveform. Wavelet domain coefficients were modulated while iteratively running a Bloch equation simulator to generate the intermediate slice profile of the net magnetization. The algorithm minimizes the L2-norm of the slice profile with additional terms to penalize rejection band ripple and maximize the net transverse magnetization across each slice. Simulations and human brain imaging were used to demonstrate a new RF pulse design that yields an optimized slice profile and reduced peak energy deposition when applied to a multiband single-shot echo planar diffusion acquisition. This method may be used to optimize factors such as magnitude and phase spectral profiles and peak RF pulse power for multiband simultaneous multi-slice (SMS acquisitions. Wavelet-based RF pulse optimization provides a useful design method to achieve a pulse waveform with beneficial amplitude reduction while preserving appropriate magnetization response for magnetic resonance imaging.

  11. Synchrotron X-ray imaging applied to solar photovoltaic silicon

    International Nuclear Information System (INIS)

    Lafford, T A; Villanova, J; Plassat, N; Dubois, S; Camel, D

    2013-01-01

    Photovoltaic (PV) cell performance is dictated by the material of the cell, its quality and purity, the type, quantity, size and distribution of defects, as well as surface treatments, deposited layers and contacts. A synchrotron offers unique opportunities for a variety of complementary X-ray techniques, given the brilliance, spectrum, energy tunability and potential for (sub-) micron-sized beams. Material properties are revealed within in the bulk and at surfaces and interfaces. X-ray Diffraction Imaging (X-ray Topography), Rocking Curve Imaging and Section Topography reveal defects such as dislocations, inclusions, misorientations and strain in the bulk and at surfaces. Simultaneous measurement of micro-X-Ray Fluorescence (μ-XRF) and micro-X-ray Beam Induced Current (μ-XBIC) gives direct correlation between impurities and PV performance. Together with techniques such as microscopy and Light Beam Induced Current (LBIC) measurements, the correlation between structural properties and photovoltaic performance can be deduced, as well as the relative influence of parameters such as defect type, size, spatial distribution and density (e.g [1]). Measurements may be applied at different stages of solar cell processing in order to follow the evolution of the material and its properties through the manufacturing process. Various grades of silicon are under study, including electronic and metallurgical grades in mono-crystalline, multi-crystalline and mono-like forms. This paper aims to introduce synchrotron imaging to non-specialists, giving example results on selected solar photovoltaic silicon samples.

  12. Laser-Induced Thermal Acoustics Theory and Expected Experimental Errors when Applied to a Scramjet Isolator Model

    Science.gov (United States)

    Middleton, Troy F.; Balla, Robert Jeffrey; Baurle, Robert A.; Wilson, Lloyd G.

    2011-01-01

    A scramjet isolator model test apparatus is being assembled in the Isolator Dynamics Research Lab (IDRL) at the NASA Langley Research Center in Hampton, Virginia. The test apparatus is designed to support multiple measurement techniques for investigating the flow field in a scramjet isolator model. The test section is 1-inch high by 2-inch wide by 24-inch long and simulates a scramjet isolator with an aspect ratio of two. Unheated, dry air at a constant stagnation pressure and temperature is delivered to the isolator test section through a Mach 2.5 planar nozzle. The isolator test section is mechanically back-pressured to contain the resulting shock train within the 24-inch isolator length and supports temperature, static pressure, and high frequency pressure measurements at the wall. Additionally, nonintrusive methods including laser-induced thermal acoustics (LITA), spontaneous Raman scattering, particle image velocimetry, and schlieren imaging are being incorporated to measure off-wall fluid dynamic, thermodynamic, and transport properties of the flow field. Interchangeable glass and metallic sidewalls and optical access appendages permit making multiple measurements simultaneously. The measurements will be used to calibrate computational fluid dynamics turbulence models and characterize the back-pressured flow of a scramjet isolator. This paper describes the test apparatus, including the optical access appendages; the physics of the LITA method; and estimates of LITA measurement uncertainty for measurements of the speed of sound and temperature.

  13. Acoustic Characterization and Enhanced Ultrasound Imaging of Long-Circulating Lipid-Coated Microbubbles.

    Science.gov (United States)

    Li, Hongbo; Yang, Yanye; Zhang, Meimei; Yin, Liping; Tu, Juan; Guo, Xiasheng; Zhang, Dong

    2018-05-01

    A long-circulating lipid-coated ultrasound (US) contrast agent was fabricated to achieve a longer wash-out time and gain more resistance against higher-mechanical index sonication. Systemic physical, acoustic, and in vivo imaging experiments were performed to better understand the underlying mechanism enabling the improvement of contrast agent performance by adjusting the physical and acoustic properties of contrast agent microbubbles. By simply altering the gas core, a kind of US contrast agent microbubble was synthesized with a similar lipid-coating shell as SonoVue microbubbles (Bracco SpA, Milan, Italy) to achieve a longer wash-out time and higher inertial cavitation threshold. To bridge the structure-performance relationship of the synthesized microbubbles, the imaging performance of the microbubbles was assessed in vivo with SonoVue as a control group. The size distribution and inertial cavitation threshold of the synthesized microbubbles were characterized, and the shell parameters of the microbubbles were determined by acoustic attenuation measurements. All of the measurements were compared with SonoVue microbubbles. The synthesized microbubbles had a spherical shape, a smooth, consistent membrane, and a uniform distribution, with an average diameter of 1.484 μm. According to the measured attenuation curve, the synthesized microbubbles resonated at around 2.8 MHz. Although the bubble's shell elasticity (0.2 ± 0.09 N/m) was comparable with SonoVue, it had relatively greater viscosity and inertial cavitation because of the different gas core. Imaging studies showed that the synthesized microbubbles had a longer circulation time and a better chance of fighting against rapid collapse than SonoVue. Nano/micrometer long-circulating lipid-coated microbubbles could be fabricated by simply altering the core composition of SonoVue microbubbles with a higher-molecular weight gas. The smaller diameter and higher inertial cavitation threshold of the

  14. Efforts regarding acoustical education for architectural students at the Universidad Peruana de Ciencias Aplicadas (Peruvian University of Applied Sciences), UPC

    Science.gov (United States)

    Moy, Jorge

    2002-11-01

    The lack of knowledge in acoustics among the vast majority of Peruvian architects results in acoustical problems in buildings from a lack of such considerations in the design stage. This paucity of knowledge on the part of the architects may be attributed to the lack of emphasis on the role of acoustics in most architectural curricula in Peruvian universities. A purpose in this paper is to present a brief report on last year's efforts to implement courses in Architectural Acoustics and Noise Control for architecture students at UPC.

  15. Applied Fourier analysis from signal processing to medical imaging

    CERN Document Server

    Olson, Tim

    2017-01-01

    The first of its kind, this focused textbook serves as a self-contained resource for teaching from scratch the fundamental mathematics of Fourier analysis and illustrating some of its most current, interesting applications, including medical imaging and radar processing. Developed by the author from extensive classroom teaching experience, it provides a breadth of theory that allows students to appreciate the utility of the subject, but at as accessible a depth as possible. With myriad applications included, this book can be adapted to a one or two semester course in Fourier Analysis or serve as the basis for independent study. Applied Fourier Analysis assumes no prior knowledge of analysis from its readers, and begins by making the transition from linear algebra to functional analysis. It goes on to cover basic Fourier series and Fourier transforms before delving into applications in sampling and interpolation theory, digital communications, radar processing, medical i maging, and heat and wave equations. Fo...

  16. Elastic models: a comparative study applied to retinal images.

    Science.gov (United States)

    Karali, E; Lambropoulou, S; Koutsouris, D

    2011-01-01

    In this work various methods of parametric elastic models are compared, namely the classical snake, the gradient vector field snake (GVF snake) and the topology-adaptive snake (t-snake), as well as the method of self-affine mapping system as an alternative to elastic models. We also give a brief overview of the methods used. The self-affine mapping system is implemented using an adapting scheme and minimum distance as optimization criterion, which is more suitable for weak edges detection. All methods are applied to glaucomatic retinal images with the purpose of segmenting the optical disk. The methods are compared in terms of segmentation accuracy and speed, as these are derived from cross-correlation coefficients between real and algorithm extracted contours and segmentation time, respectively. As a result, the method of self-affine mapping system presents adequate segmentation time and segmentation accuracy, and significant independence from initialization.

  17. Non-Imaging Acoustical Properties in Monitoring Arteriovenous Hemodialysis Access. A Review

    Directory of Open Access Journals (Sweden)

    Anas Mohd Noor

    2015-12-01

    Full Text Available The limitations of the gold standard angiography technique in arteriovenous access surveillance have opened a gap for researchers to find the best way to monitor this condition with low-cost, non-invasive and continuous bedside monitoring. The phonoangiography technique has been developed prior to these limits. This measurement and monitoring technique, associated with intelligence signal processing, promises better analysis for early detection of hemodialysis access problems, such as stenosis and thrombosis. Some research groups have shown that the phonoangiography technique could identify as many as 20% of vascular diameter changes and also its frequency characteristics due to hemodialysis access problems. The frequency characteristics of these acoustical signals are presented and discussed in detail to understand the association with the stenosis level, blood flows, sensor locations, fundamental frequency bands of normal and abnormal conditions, and also the spectral energy produced. This promising technique could be used in the near future as a tool for pre-diagnosis of arteriovenous access before any further access correction by surgical techniques is required. This paper provides an extensive review of various arteriovenous access monitoring techniques based on non-imaging acoustical properties.

  18. A cross-correlation objective function for least-squares migration and visco-acoustic imaging

    KAUST Repository

    Dutta, Gaurav

    2014-08-05

    Conventional acoustic least-squares migration inverts for a reflectivity image that best matches the amplitudes of the observed data. However, for field data applications, it is not easy to match the recorded amplitudes because of the visco-elastic nature of the earth and inaccuracies in the estimation of source signature and strength at different shot locations. To relax the requirement for strong amplitude matching of least-squares migration, we use a normalized cross-correlation objective function that is only sensitive to the similarity between the predicted and the observed data. Such a normalized cross-correlation objective function is also equivalent to a time-domain phase inversion method where the main emphasis is only on matching the phase of the data rather than the amplitude. Numerical tests on synthetic and field data show that such an objective function can be used as an alternative to visco-acoustic least-squares reverse time migration (Qp-LSRTM) when there is strong attenuation in the subsurface and the estimation of the attenuation parameter Qp is insufficiently accurate.

  19. A cross-correlation objective function for least-squares migration and visco-acoustic imaging

    KAUST Repository

    Dutta, Gaurav; Sinha, Mrinal; Schuster, Gerard T.

    2014-01-01

    Conventional acoustic least-squares migration inverts for a reflectivity image that best matches the amplitudes of the observed data. However, for field data applications, it is not easy to match the recorded amplitudes because of the visco-elastic nature of the earth and inaccuracies in the estimation of source signature and strength at different shot locations. To relax the requirement for strong amplitude matching of least-squares migration, we use a normalized cross-correlation objective function that is only sensitive to the similarity between the predicted and the observed data. Such a normalized cross-correlation objective function is also equivalent to a time-domain phase inversion method where the main emphasis is only on matching the phase of the data rather than the amplitude. Numerical tests on synthetic and field data show that such an objective function can be used as an alternative to visco-acoustic least-squares reverse time migration (Qp-LSRTM) when there is strong attenuation in the subsurface and the estimation of the attenuation parameter Qp is insufficiently accurate.

  20. Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Laurell, Thomas

    2012-01-01

    We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10μm undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming...

  1. The results of borehole acoustic imaging from a granite in the Jihlava District, Czech Republic: implications for structural geological research

    Czech Academy of Sciences Publication Activity Database

    Nováková, Lucie; Novák, P.; Brož, Milan; Sosna, K.; Pitrák, K.; Kasíková, J.; Rukavičková, L.; Maňák, L.

    2012-01-01

    Roč. 4, č. 4 (2012), s. 92-101 ISSN 1916-9779 R&D Projects: GA MPO(CZ) FR-TI1/367 Institutional research plan: CEZ:AV0Z30460519 Keywords : acoustic borehole imaging * structural geology * paleostress analysis Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  2. Sci-Thur AM: YIS – 02: Imaging dose distributions through the detection of radiation-induced acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Hickling, Susannah; Lei, Hao; Hobson, Maritza; Leger, Pierre; Wang, Xueding; El Naqa, Issam [University of Michigan, McGill University, McGill University , University of Michigan, University of Michigan/McGill University (United States)

    2016-08-15

    Purpose: X-ray acoustic computed tomography (XACT) is an emerging technique that images the dose deposited within an object following linac irradiation by detecting acoustic waves induced via the photoacoustic effect. This work shows that XACT images can be formed in soft-tissue equivalent material and that dosimetric information can be extracted from such images. Methods: Acoustic waves induced in a water tank following irradiation by a 10 MV flattening filter free photon beam were detected with an immersion ultrasound transducer at 60 angles surrounding the radiation field. A back-projection algorithm was used to reconstruct an XACT image from the detected transducer signals. Profiles extracted from XACT images were compared to profiles measured with ion chambers as per the current clinical protocol. Results: XACT images were successfully formed of simple 4 cm × 4 cm and 6 cm × 3 cm fields, as well as of more complicated multi-leaf collimator defined fields. For the 6 cm × 3 cm field, 74% and 87% of the XACT profile points in the 6 cm and 3 cm dimensions, respectively, passed a 7% / 4 mm gamma test when compared to ion chamber measurements. In a complicated puzzle piece shaped field, 86% of the pixels in an extracted profile passed a 7% / 4 mm gamma test. Conclusions: XACT is capable of imaging the dose distribution delivered by a variety of field sizes and shapes in water, and is a viable technique for both water tank and in vivo dosimetry.

  3. Particle image and acoustic Doppler velocimetry analysis of a cross-flow turbine wake

    Science.gov (United States)

    Strom, Benjamin; Brunton, Steven; Polagye, Brian

    2017-11-01

    Cross-flow turbines have advantageous properties for converting kinetic energy in wind and water currents to rotational mechanical energy and subsequently electrical power. A thorough understanding of cross-flow turbine wakes aids understanding of rotor flow physics, assists geometric array design, and informs control strategies for individual turbines in arrays. In this work, the wake physics of a scale model cross-flow turbine are investigated experimentally. Three-component velocity measurements are taken downstream of a two-bladed turbine in a recirculating water channel. Time-resolved stereoscopic particle image and acoustic Doppler velocimetry are compared for planes normal to and distributed along the turbine rotational axis. Wake features are described using proper orthogonal decomposition, dynamic mode decomposition, and the finite-time Lyapunov exponent. Consequences for downstream turbine placement are discussed in conjunction with two-turbine array experiments.

  4. A spinal cord window chamber model for in vivo longitudinal multimodal optical and acoustic imaging in a murine model.

    Directory of Open Access Journals (Sweden)

    Sarah A Figley

    Full Text Available In vivo and direct imaging of the murine spinal cord and its vasculature using multimodal (optical and acoustic imaging techniques could significantly advance preclinical studies of the spinal cord. Such intrinsically high resolution and complementary imaging technologies could provide a powerful means of quantitatively monitoring changes in anatomy, structure, physiology and function of the living cord over time after traumatic injury, onset of disease, or therapeutic intervention. However, longitudinal in vivo imaging of the intact spinal cord in rodent models has been challenging, requiring repeated surgeries to expose the cord for imaging or sacrifice of animals at various time points for ex vivo tissue analysis. To address these limitations, we have developed an implantable spinal cord window chamber (SCWC device and procedures in mice for repeated multimodal intravital microscopic imaging of the cord and its vasculature in situ. We present methodology for using our SCWC to achieve spatially co-registered optical-acoustic imaging performed serially for up to four weeks, without damaging the cord or induction of locomotor deficits in implanted animals. To demonstrate the feasibility, we used the SCWC model to study the response of the normal spinal cord vasculature to ionizing radiation over time using white light and fluorescence microscopy combined with optical coherence tomography (OCT in vivo. In vivo power Doppler ultrasound and photoacoustics were used to directly visualize the cord and vascular structures and to measure hemoglobin oxygen saturation through the complete spinal cord, respectively. The model was also used for intravital imaging of spinal micrometastases resulting from primary brain tumor using fluorescence and bioluminescence imaging. Our SCWC model overcomes previous in vivo imaging challenges, and our data provide evidence of the broader utility of hybridized optical-acoustic imaging methods for obtaining

  5. Advanced imaging systems for diagnostic investigations applied to Cultural Heritage

    International Nuclear Information System (INIS)

    Peccenini, E; Bettuzzi, M; Brancaccio, R; Casali, F; Morigi, M P; Albertin, F; Petrucci, F

    2014-01-01

    The diagnostic investigations are an important resource in the studies on Cultural Heritage to enhance the knowledge on execution techniques, materials and conservation status of a work of art. In this field, due to the great historical and artistic value of the objects, preservation is the main concern; for this reason, new technological equipment has been designed and developed in the Physics Departments of the Universities of Ferrara and Bologna to enhance the non-invasive approach to the study of pictorial artworks and other objects of cultural interest. Infrared (IR) reflectography, X-ray radiography and computed tomography (CT), applied to works of art, are joined by the same goal: to get hidden information on execution techniques and inner structure pursuing the non-invasiveness of the methods, although using different setup and physical principles. In this work transportable imaging systems to investigate large objects in museums and galleries are presented. In particular, 2D scanning devices for IR reflectography and X-ray radiography, CT systems and some applications to the Cultural Heritage are described

  6. Advanced imaging systems for diagnostic investigations applied to Cultural Heritage

    Science.gov (United States)

    Peccenini, E.; Albertin, F.; Bettuzzi, M.; Brancaccio, R.; Casali, F.; Morigi, M. P.; Petrucci, F.

    2014-12-01

    The diagnostic investigations are an important resource in the studies on Cultural Heritage to enhance the knowledge on execution techniques, materials and conservation status of a work of art. In this field, due to the great historical and artistic value of the objects, preservation is the main concern; for this reason, new technological equipment has been designed and developed in the Physics Departments of the Universities of Ferrara and Bologna to enhance the non-invasive approach to the study of pictorial artworks and other objects of cultural interest. Infrared (IR) reflectography, X-ray radiography and computed tomography (CT), applied to works of art, are joined by the same goal: to get hidden information on execution techniques and inner structure pursuing the non-invasiveness of the methods, although using different setup and physical principles. In this work transportable imaging systems to investigate large objects in museums and galleries are presented. In particular, 2D scanning devices for IR reflectography and X-ray radiography, CT systems and some applications to the Cultural Heritage are described.

  7. Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

    Directory of Open Access Journals (Sweden)

    Ben Minnaert

    2017-01-01

    Full Text Available Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this optimal network as a function of the characteristics of the capacitive wireless link, as well for the series as for the parallel topology. The results are compared with the inductive power transfer system. Introduction of a new concept, the coupling function, enables the description of the compensation network of both an inductive and a capacitive system in two elegant equations, valid for the series and the parallel topology. This approach allows better understanding of the fundamentals of the wireless power transfer link, necessary for the design of an efficient system.

  8. Fat suppression applied to MR imaging of the pathologic orbit

    International Nuclear Information System (INIS)

    Simon, J.H.; Kido, D.K.; Ekholm, S.E.; Totterman, S.; Szumowski, J.; Manzione, J.V. Jr.; Joy, S.E.

    1987-01-01

    Previous MR studies of the normal orbit have shown that fat suppression sequences applied at the proper T1-T2 weighting will decrease artifacts from chemical shift, and can be used to enhance contrast in selected anatomic regions. The purpose of this study was to evaluate the clinical application of fat suppression to studies of the pathologic orbit. The studies included conventional imaging sequences and comparative fat suppression sequences through a range of T1-T2 weighting (repetition time [TR] 400 msec, echo time [TE]20 msec, to TR 2,000 msec, TE 90 msec), using the chopper fat suppression technique developed by J. Szumowski and D. Plewes, which requires no postprocessing and no increased scan time to achieve relatively linear fat suppression. Fat suppression was advantageous in determining tumor margins (extension through sclera); increasing diagnostic specificity (fat vs. water content); detailing anatomic relationships along bony margins (particularly in the orbital apex); and for demonstrating true thickness of optic nerve separate from adjacent cerebrospinal fluid and fibrous sheath. Disadvantages included susceptibility to motion artifact and a perception of lower quality due to lower overall orbital signal

  9. Spatially resolved acoustic spectroscopy for rapid imaging of material microstructure and grain orientation

    International Nuclear Information System (INIS)

    Smith, Richard J; Li, Wenqi; Coulson, Jethro; Clark, Matt; Somekh, Michael G; Sharples, Steve D

    2014-01-01

    Measuring the grain structure of aerospace materials is very important to understand their mechanical properties and in-service performance. Spatially resolved acoustic spectroscopy is an acoustic technique utilizing surface acoustic waves to map the grain structure of a material. When combined with measurements in multiple acoustic propagation directions, the grain orientation can be obtained by fitting the velocity surface to a model. The new instrument presented here can take thousands of acoustic velocity measurements per second. The spatial and velocity resolution can be adjusted by simple modification to the system; this is discussed in detail by comparison of theoretical expectations with experimental data. (paper)

  10. A study on applying image dictionary to inner organ registration

    International Nuclear Information System (INIS)

    Matsuno, Takamichi; Asai, Takeshi; Iwata, Takuya; Hontani, Hidekata

    2010-01-01

    In this article, we report on selecting image features that are useful for registering organ surface in medical image based on image dictionary constructed for the organ. Here, the image dictionary denotes a basis set, which is non-orthogonal and over-complete one and is designed to represent images of the target organ. We propose a method that refers to a combination of the basis obtained for reconstructing a given image in order to estimate the location of the target organ. (author)

  11. Visual Analytics Applied to Image Analysis : From Segmentation to Classification

    NARCIS (Netherlands)

    Rauber, Paulo

    2017-01-01

    Image analysis is the field of study concerned with extracting information from images. This field is immensely important for commercial and scientific applications, from identifying people in photographs to recognizing diseases in medical images. The goal behind the work presented in this thesis is

  12. Effect of MRI acoustic noise on cerebral fludeoxyglucose uptake in simultaneous MR-PET imaging.

    Science.gov (United States)

    Chonde, Daniel B; Abolmaali, Nasreddin; Arabasz, Grae; Guimaraes, Alexander R; Catana, Ciprian

    2013-05-01

    Integrated scanners capable of simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) data acquisition are now available for human use. Although the scanners' manufacturers have made substantial efforts to understand and minimize the mutual electromagnetic interference between the 2 modalities, the potential physiological inference has not been evaluated. In this study, we have studied the influence of the acoustic noise produced by the magnetic resonance (MR) gradients on brain fludeoxyglucose (FDG) uptake in the Siemens MR-BrainPET prototype. Although particular attention was paid to the primary auditory cortex (PAC), a brain-wide analysis was also performed. The effects of the MR on the PET count rate and image quantification were first investigated in phantoms. Next, 10 healthy volunteers underwent 2 simultaneous FDG-PET/MR scans in the supine position with the FDG injection occurring inside the MR-BrainPET, alternating between a "quiet" (control) environment in which no MR sequences were run during the FDG uptake phase (the first 40 minutes after radiotracer administration) and a "noisy" (test) environment in which MR sequences were run for the entire time. Cortical and subcortical regions of interest were derived from the high-resolution morphological MR data using FreeSurfer. The changes in the FDG uptake in the FreeSurfer-derived regions of interest between the 2 conditions were analyzed from parametric and static PET images, and on a voxel-by-voxel basis using SPM8 and FreeSurfer. Only minimal to no electromagnetic interference was observed for most of the MR sequences tested, with a maximum drop in count rate of 1.5% and a maximum change in the measured activity of 1.1% in the corresponding images. The region of interest-based analysis showed statistically significant increases in the right PAC in both the parametric (9.13% [4.73%]) and static (4.18% [2.87%]) images. The SPM8 analysis showed no statistically significant

  13. Real-time contrast ultrasound muscle perfusion imaging with intermediate-power imaging coupled with acoustically durable microbubbles.

    Science.gov (United States)

    Seol, Sang-Hoon; Davidson, Brian P; Belcik, J Todd; Mott, Brian H; Goodman, Reid M; Ammi, Azzdine; Lindner, Jonathan R

    2015-06-01

    There is growing interest in limb contrast-enhanced ultrasound (CEU) perfusion imaging for the evaluation of peripheral artery disease. Because of low resting microvascular blood flow in skeletal muscle, signal enhancement during limb CEU is prohibitively low for real-time imaging. The aim of this study was to test the hypothesis that this obstacle can be overcome by intermediate- rather than low-power CEU when performed with an acoustically resilient microbubble agent. Viscoelastic properties of Definity and Sonazoid were assessed by measuring bulk modulus during incremental increases in ambient pressure to 200 mm Hg. Comparison of in vivo microbubble destruction and signal enhancement at a mechanical index (MI) of 0.1 to 0.4 was performed by sequential reduction in pulsing interval from 10 to 0.05 sec during limb CEU at 7 MHz in mice and 1.8 MHz in dogs. Destruction was also assessed by broadband signal generation during passive cavitation detection. Real-time CEU perfusion imaging with destruction-replenishment was then performed at 1.8 MHz in dogs using an MI of 0.1, 0.2, or 0.3. Sonazoid had a higher bulk modulus than Definity (66 ± 12 vs 29 ± 2 kPa, P = .02) and exhibited less inertial cavitation (destruction) at MIs ≥ 0.2. On in vivo CEU, maximal signal intensity increased incrementally with MI for both agents and was equivalent between agents except at an MI of 0.1 (60% and 85% lower for Sonazoid at 7 and 1.8 MHz, respectively, P power imaging coupled with a durable microbubble contrast agent. Copyright © 2015 American Society of Echocardiography. All rights reserved.

  14. Extraction of Overt Verbal Response from the Acoustic Noise in a Functional Magnetic Resonance Imaging Scan by Use of Segmented Active Noise Cancellation

    Science.gov (United States)

    Jung, Kwan-Jin; Prasad, Parikshit; Qin, Yulin; Anderson, John R.

    2013-01-01

    A method to extract the subject's overt verbal response from the obscuring acoustic noise in an fMRI scan is developed by applying active noise cancellation with a conventional MRI microphone. Since the EPI scanning and its accompanying acoustic noise in fMRI are repetitive, the acoustic noise in one time segment was used as a reference noise in suppressing the acoustic noise in subsequent segments. However, the acoustic noise from the scanner was affected by the subject's movements, so the reference noise was adaptively adjusted as the scanner's acoustic properties varied in time. This method was successfully applied to a cognitive fMRI experiment with overt verbal responses. PMID:15723385

  15. An electrochemical and high-speed imaging study of micropore decontamination by acoustic bubble entrapment.

    Science.gov (United States)

    Offin, Douglas G; Birkin, Peter R; Leighton, Timothy G

    2014-03-14

    Electrochemical and high-speed imaging techniques are used to study the abilities of ultrasonically-activated bubbles to clean out micropores. Cylindrical pores with dimensions (diameter × depth) of 500 μm × 400 μm (aspect ratio 0.8), 125 μm × 350 μm (aspect ratio 2.8) and 50 μm × 200 μm (aspect ratio 4.0) are fabricated in glass substrates. Each pore is contaminated by filling it with an electrochemically inactive blocking organic material (thickened methyl salicylate) before the substrate is placed in a solution containing an electroactive species (Fe(CN)6(3-)). An electrode is fabricated at the base of each pore and the Faradaic current is used to monitor the decontamination as a function of time. For the largest pore, decontamination driven by ultrasound (generated by a horn type transducer) and bulk fluid flow are compared. It is shown that ultrasound is much more effective than flow alone, and that bulk fluid flow at the rates used cannot decontaminate the pore completely, but that ultrasound can. In the case of the 125 μm pore, high-speed imaging is used to elucidate the cleaning mechanisms involved in ultrasonic decontamination and reveals that acoustic bubble entrapment is a key feature. The smallest pore is used to explore the limits of decontamination and it is found that ultrasound is still effective at this size under the conditions employed.

  16. Imaging the Chicxulub central crater zone from large scale seismic acoustic wave propagation and gravity modeling

    Science.gov (United States)

    Fucugauchi, J. U.; Ortiz-Aleman, C.; Martin, R.

    2017-12-01

    Large complex craters are characterized by central uplifts that represent large-scale differential movement of deep basement from the transient cavity. Here we investigate the central sector of the large multiring Chicxulub crater, which has been surveyed by an array of marine, aerial and land-borne geophysical methods. Despite high contrasts in physical properties,contrasting results for the central uplift have been obtained, with seismic reflection surveys showing lack of resolution in the central zone. We develop an integrated seismic and gravity model for the main structural elements, imaging the central basement uplift and melt and breccia units. The 3-D velocity model built from interpolation of seismic data is validated using perfectly matched layer seismic acoustic wave propagation modeling, optimized at grazing incidence using shift in the frequency domain. Modeling shows significant lack of illumination in the central sector, masking presence of the central uplift. Seismic energy remains trapped in an upper low velocity zone corresponding to the sedimentary infill, melt/breccias and surrounding faulted blocks. After conversion of seismic velocities into a volume of density values, we use massive parallel forward gravity modeling to constrain the size and shape of the central uplift that lies at 4.5 km depth, providing a high-resolution image of crater structure.The Bouguer anomaly and gravity response of modeled units show asymmetries, corresponding to the crater structure and distribution of post-impact carbonates, breccias, melt and target sediments

  17. Assessment of liver steatosis in chicken by using acoustic radiation force impulse imaging: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Guzman Aroca, Florentina; Serrano, Laura; Berna-Serna, Juan D.; Reus, Manuel [Virgen de la Arrixaca University Hospital, Department of Radiology, El Palmar, Murcia (Spain); Ayala, Ignacio [University of Murcia, Department of Animal Medicine and Surgery, Murcia (Spain); Castell, Maria T. [University of Murcia, Department of Cell Biology, Murcia (Spain); Garcia-Perez, Bartolome [Virgen de la Arrixaca University Hospital, Internal Medicine Service, El Palmar, Murcia (Spain)

    2010-10-15

    To evaluate acoustic radiation force impulse (ARFI) imaging as a non-invasive tool for quantification of the grades of liver steatosis in chickens. We used two different diets: a standard diet (SD group) and a hyperlipidaemic diet (HD group). The ARFI technique was performed in all the animals in the right hepatic lobe and shear wave velocity (SWV) was measured and expressed in metres per second (m/s). Plasma lipid levels were analysed. Steatosis was quantified by using semiquantitative analysis. Statistical analysis was used and Pearson's correlation coefficient was calculated. Mean SWV was 0.94 {+-} 0.16 m/s (range 0.8-1.3 m/s) in the SD group and 1.91 {+-} 0.25 m/s (range 1.3-2.2 m/s) in the HD group (p < 0.001). The lowest SWVs ({<=}1.3 m/s) corresponded to the chickens in the SD group, with 100% of the animals returning a score of 0, whereas the range of SWV in the HD group chickens was between 1.6 and 2.2 m/s. A substantial correlation was observed between SWVs with histological semiquantitative analysis of steatosis (r = 0.85, p < 0.001). ARFI imaging is a non-invasive diagnostic tool that allows discrimination between the grades of liver steatosis in chickens. (orig.)

  18. Assessment of liver steatosis in chicken by using acoustic radiation force impulse imaging: preliminary results

    International Nuclear Information System (INIS)

    Guzman Aroca, Florentina; Serrano, Laura; Berna-Serna, Juan D.; Reus, Manuel; Ayala, Ignacio; Castell, Maria T.; Garcia-Perez, Bartolome

    2010-01-01

    To evaluate acoustic radiation force impulse (ARFI) imaging as a non-invasive tool for quantification of the grades of liver steatosis in chickens. We used two different diets: a standard diet (SD group) and a hyperlipidaemic diet (HD group). The ARFI technique was performed in all the animals in the right hepatic lobe and shear wave velocity (SWV) was measured and expressed in metres per second (m/s). Plasma lipid levels were analysed. Steatosis was quantified by using semiquantitative analysis. Statistical analysis was used and Pearson's correlation coefficient was calculated. Mean SWV was 0.94 ± 0.16 m/s (range 0.8-1.3 m/s) in the SD group and 1.91 ± 0.25 m/s (range 1.3-2.2 m/s) in the HD group (p < 0.001). The lowest SWVs (≤1.3 m/s) corresponded to the chickens in the SD group, with 100% of the animals returning a score of 0, whereas the range of SWV in the HD group chickens was between 1.6 and 2.2 m/s. A substantial correlation was observed between SWVs with histological semiquantitative analysis of steatosis (r = 0.85, p < 0.001). ARFI imaging is a non-invasive diagnostic tool that allows discrimination between the grades of liver steatosis in chickens. (orig.)

  19. Effect of aberration on the acoustic field in tissue harmonic imaging (THI)

    Science.gov (United States)

    Jing, Yuan; Cleveland, Robin

    2003-10-01

    A numerical simulation was used to study the impact of an aberrating layer on the generation of the fundamental and second-harmonic (SH) field in a tissue harmonic imaging scenario. The simulation used a three-dimensional time-domain code for solving the KZK equation and accounted for arbitrary spatial variations in all acoustic properties. The aberration effect was modeled by assuming that the tissue consisted of two layers where the interface has a spatial variation C that acted like an effective phase screen. Initial experiments were carried out with sinusoidal-shaped interfaces. The sinusoidal interface produced grating lobes which were at least 6 dB larger for the fundamental signal than the SH. The energy outside of the main lobe was found to increase linearly as the amplitude of the interface variation increased. The location of the grating lobes was affected by the spatial period on the interface variation. The inhomogeneous nature of tissue was modeled with an interface with a random spatial variation. With the random interface the average sidelobe level for the fundamental was -30 dB whereas the SH had an average sidelobe level of -36 dB. [Work supported by the NSF through the Center for Subsurface Sensing and Imaging Systems.

  20. Effect of MRI Acoustic Noise on Cerebral FDG Uptake in Simultaneous MR-PET Imaging

    Science.gov (United States)

    Abolmaali, Nasreddin; Arabasz, Grae; Guimaraes, Alexander R.; Catana, Ciprian

    2013-01-01

    Integrated scanners capable of simultaneous PET and MRI data acquisition are now available for human use. Although the scanners’ manufacturers have made substantial efforts to understand and minimize the mutual electromagnetic interference between the two modalities, the potential physiological inference has not been evaluated. In this work, we have studied the influence of the acoustic noise produced by the MR gradients on brain FDG uptake in the Siemens MR-BrainPET prototype. While particular attention was paid to the primary auditory cortex (PAC), a brain-wide analysis was also performed. Methods The effects of the MR on the PET count rate and image quantification were first investigated in phantoms. Next, ten healthy volunteers underwent two simultaneous FDG-PET/MR scans in the supine position with the FDG injection occurring inside the MR-BrainPET, alternating between a “quiet” (control) environment in which no MR sequences were run during the FDG uptake phase (the first 40 minutes after radiotracer administration) and a “noisy” (test) case in which MR sequences were run for the entire time. Cortical and subcortical regions of interest (ROIs) were derived from the high-resolution morphological MR data using FreeSurfer. The changes in FDG uptake in the FreeSurfer-derived ROIs between the two conditions were analyzed from parametric and static PET images, and on a voxel-by-voxel basis using SPM8 and FreeSurfer. Results Only minimal to no electromagnetic interference was observed for most of the MR sequences tested, with a maximum drop in count rate of 1.5% and a maximum change in the measured activity of 1.1% in the corresponding images. The ROI-based analysis showed statistically significant increases in the right PAC in both the parametric (9.13±4.73%) and static (4.18±2.87%) images. SPM8 analysis showed no statistically significant clusters in any images when a p<0.05 (corrected) was used; however, a p<0.001 (uncorrected) resolved bilateral

  1. TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

    International Nuclear Information System (INIS)

    Weavers, P; Shu, Y; Tao, S; Bernstein, M; Lee, S; Piel, J; Foo, T; Mathieu, J-B

    2015-01-01

    Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065

  2. TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

    Energy Technology Data Exchange (ETDEWEB)

    Weavers, P; Shu, Y; Tao, S; Bernstein, M [Mayo Clinic, Rochester, Minnesota (United States); Lee, S; Piel, J; Foo, T [GE Global Research, Niskayuna, NY (United States); Mathieu, J-B [GE Healthcare, Florence, SC (Italy)

    2015-06-15

    Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065.

  3. Fractional Hartley transform applied to optical image encryption

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C [Grupo GIFES. Universidad de La Guajira. Riohacha (Colombia); Torres, C; Mattos, L, E-mail: carlosj114@gmail.com [Grupo LOI. Universidad Popular del Cesar. Valledupar (Colombia)

    2011-01-01

    A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibility of proposed method.

  4. A Kalman filter technique applied for medical image reconstruction

    International Nuclear Information System (INIS)

    Goliaei, S.; Ghorshi, S.; Manzuri, M. T.; Mortazavi, M.

    2011-01-01

    Medical images contain information about vital organic tissues inside of human body and are widely used for diagnoses of disease or for surgical purposes. Image reconstruction is essential for medical images for some applications such as suppression of noise or de-blurring the image in order to provide images with better quality and contrast. Due to vital rule of image reconstruction in medical sciences the corresponding algorithms with better efficiency and higher speed is desirable. Most algorithms in image reconstruction are operated on frequency domain such as the most popular one known as filtered back projection. In this paper we introduce a Kalman filter technique which is operated in time domain for medical image reconstruction. Results indicated that as the number of projection increases in both normal collected ray sum and the collected ray sum corrupted by noise the quality of reconstructed image becomes better in terms of contract and transparency. It is also seen that as the number of projection increases the error index decreases.

  5. Fractional Hartley transform applied to optical image encryption

    Science.gov (United States)

    Jimenez, C.; Torres, C.; Mattos, L.

    2011-01-01

    A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibilty of proposed method.

  6. Differential diagnosis of idiopathic granulomatous mastitis and breast cancer using acoustic radiation force impulse imaging.

    Science.gov (United States)

    Teke, Memik; Teke, Fatma; Alan, Bircan; Türkoğlu, Ahmet; Hamidi, Cihad; Göya, Cemil; Hattapoğlu, Salih; Gumus, Metehan

    2017-01-01

    Differentiation of idiopathic granulomatous mastitis (IGM) from carcinoma with routine imaging methods, such as ultrasonography (US) and mammography, is difficult. Therefore, we evaluated the value of a newly developed noninvasive technique called acoustic radiation force impulse imaging in differentiating IGM versus malignant lesions in the breast. Four hundred and eighty-six patients, who were referred to us with a presumptive diagnosis of a mass, underwent Virtual Touch tissue imaging (VTI; Siemens) and Virtual Touch tissue quantification (VTQ; Siemens) after conventional gray-scale US. US-guided percutaneous needle biopsy was then performed on 276 lesions with clinically and radiologically suspicious features. Malignant lesions (n = 122) and IGM (n = 48) were included in the final study group. There was a statistically significant difference in shear wave velocity marginal and internal values between the IGM and malignant lesions. The median marginal velocity for IGM and malignant lesions was 3.19 m/s (minimum-maximum 2.49-5.82) and 5.05 m/s (minimum-maximum 2.09-8.46), respectively (p < 0.001). The median internal velocity for IGM and malignant lesions was 2.76 m/s (minimum-maximum 1.14-4.12) and 4.79 m/s (minimum-maximum 2.12-8.02), respectively (p < 0.001). The combination of VTI and VTQ as a complement to conventional US provides viscoelastic properties of tissues, and thus has the potential to increase the specificity of US.

  7. Improved Bat Algorithm Applied to Multilevel Image Thresholding

    Directory of Open Access Journals (Sweden)

    Adis Alihodzic

    2014-01-01

    Full Text Available Multilevel image thresholding is a very important image processing technique that is used as a basis for image segmentation and further higher level processing. However, the required computational time for exhaustive search grows exponentially with the number of desired thresholds. Swarm intelligence metaheuristics are well known as successful and efficient optimization methods for intractable problems. In this paper, we adjusted one of the latest swarm intelligence algorithms, the bat algorithm, for the multilevel image thresholding problem. The results of testing on standard benchmark images show that the bat algorithm is comparable with other state-of-the-art algorithms. We improved standard bat algorithm, where our modifications add some elements from the differential evolution and from the artificial bee colony algorithm. Our new proposed improved bat algorithm proved to be better than five other state-of-the-art algorithms, improving quality of results in all cases and significantly improving convergence speed.

  8. Wavelet compression algorithm applied to abdominal ultrasound images

    International Nuclear Information System (INIS)

    Lin, Cheng-Hsun; Pan, Su-Feng; LU, Chin-Yuan; Lee, Ming-Che

    2006-01-01

    We sought to investigate acceptable compression ratios of lossy wavelet compression on 640 x 480 x 8 abdominal ultrasound (US) images. We acquired 100 abdominal US images with normal and abnormal findings from the view station of a 932-bed teaching hospital. The US images were then compressed at quality factors (QFs) of 3, 10, 30, and 50 followed outcomes of a pilot study. This was equal to the average compression ratios of 4.3:1, 8.5:1, 20:1 and 36.6:1, respectively. Four objective measurements were carried out to examine and compare the image degradation between original and compressed images. Receiver operating characteristic (ROC) analysis was also introduced for subjective assessment. Five experienced and qualified radiologists as reviewers blinded to corresponding pathological findings, analysed paired 400 randomly ordered images with two 17-inch thin film transistor/liquid crystal display (TFT/LCD) monitors. At ROC analysis, the average area under curve (Az) for US abdominal image was 0.874 at the ratio of 36.6:1. The compressed image size was only 2.7% for US original at this ratio. The objective parameters showed the higher the mean squared error (MSE) or root mean squared error (RMSE) values, the poorer the image quality. The higher signal-to-noise ratio (SNR) or peak signal-to-noise ratio (PSNR) values indicated better image quality. The average RMSE, PSNR at 36.6:1 for US were 4.84 ± 0.14, 35.45 dB, respectively. This finding suggests that, on the basis of the patient sample, wavelet compression of abdominal US to a ratio of 36.6:1 did not adversely affect diagnostic performance or evaluation error for radiologists' interpretation so as to risk affecting diagnosis

  9. Applying image quality in cell phone cameras: lens distortion

    Science.gov (United States)

    Baxter, Donald; Goma, Sergio R.; Aleksic, Milivoje

    2009-01-01

    This paper describes the framework used in one of the pilot studies run under the I3A CPIQ initiative to quantify overall image quality in cell-phone cameras. The framework is based on a multivariate formalism which tries to predict overall image quality from individual image quality attributes and was validated in a CPIQ pilot program. The pilot study focuses on image quality distortions introduced in the optical path of a cell-phone camera, which may or may not be corrected in the image processing path. The assumption is that the captured image used is JPEG compressed and the cellphone camera is set to 'auto' mode. As the used framework requires that the individual attributes to be relatively perceptually orthogonal, in the pilot study, the attributes used are lens geometric distortion (LGD) and lateral chromatic aberrations (LCA). The goal of this paper is to present the framework of this pilot project starting with the definition of the individual attributes, up to their quantification in JNDs of quality, a requirement of the multivariate formalism, therefore both objective and subjective evaluations were used. A major distinction in the objective part from the 'DSC imaging world' is that the LCA/LGD distortions found in cell-phone cameras, rarely exhibit radial behavior, therefore a radial mapping/modeling cannot be used in this case.

  10. Super-Resolution Image Reconstruction Applied to Medical Ultrasound

    Science.gov (United States)

    Ellis, Michael

    Ultrasound is the preferred imaging modality for many diagnostic applications due to its real-time image reconstruction and low cost. Nonetheless, conventional ultrasound is not used in many applications because of limited spatial resolution and soft tissue contrast. Most commercial ultrasound systems reconstruct images using a simple delay-and-sum architecture on receive, which is fast and robust but does not utilize all information available in the raw data. Recently, more sophisticated image reconstruction methods have been developed that make use of far more information in the raw data to improve resolution and contrast. One such method is the Time-Domain Optimized Near-Field Estimator (TONE), which employs a maximum a priori estimation to solve a highly underdetermined problem, given a well-defined system model. TONE has been shown to significantly improve both the contrast and resolution of ultrasound images when compared to conventional methods. However, TONE's lack of robustness to variations from the system model and extremely high computational cost hinder it from being readily adopted in clinical scanners. This dissertation aims to reduce the impact of TONE's shortcomings, transforming it from an academic construct to a clinically viable image reconstruction algorithm. By altering the system model from a collection of individual hypothetical scatterers to a collection of weighted, diffuse regions, dTONE is able to achieve much greater robustness to modeling errors. A method for efficient parallelization of dTONE is presented that reduces reconstruction time by more than an order of magnitude with little loss in image fidelity. An alternative reconstruction algorithm, called qTONE, is also developed and is able to reduce reconstruction times by another two orders of magnitude while simultaneously improving image contrast. Each of these methods for improving TONE are presented, their limitations are explored, and all are used in concert to reconstruct in

  11. Applying local binary patterns in image clustering problems

    Science.gov (United States)

    Skorokhod, Nikolai N.; Elizarov, Alexey I.

    2017-11-01

    Due to the fact that the cloudiness plays a critical role in the Earth radiative balance, the study of the distribution of different types of clouds and their movements is relevant. The main sources of such information are artificial satellites that provide data in the form of images. The most commonly used method of solving tasks of processing and classification of images of clouds is based on the description of texture features. The use of a set of local binary patterns is proposed to describe the texture image.

  12. Particle and speckle imaging velocimetry applied to a monostatic LIDAR

    Science.gov (United States)

    Halldorsson, Thorsteinn; Langmeier, Andreas; Prücklmeier, Andreas; Banakh, Viktor; Falits, Andrey

    2006-11-01

    A novel backscatter-lidar imaging method of visualization of air movement in the atmosphere is discussed in the paper. The method is based on the particle image velocimetry (PIV) principle, namely: pairs of image of laser illuminated thin atmospheric layers are recorded by CCD camera and then are cross correlated to obtain velocity information from these records. Both the way of computer simulation of atmospheric version of PIV technique and the first concept proof experiments are described in the paper. It is proposed that the method can find an application for visualization of wake vortices arising behind large aircrafts.

  13. Two-dimensional DFA scaling analysis applied to encrypted images

    Science.gov (United States)

    Vargas-Olmos, C.; Murguía, J. S.; Ramírez-Torres, M. T.; Mejía Carlos, M.; Rosu, H. C.; González-Aguilar, H.

    2015-01-01

    The technique of detrended fluctuation analysis (DFA) has been widely used to unveil scaling properties of many different signals. In this paper, we determine scaling properties in the encrypted images by means of a two-dimensional DFA approach. To carry out the image encryption, we use an enhanced cryptosystem based on a rule-90 cellular automaton and we compare the results obtained with its unmodified version and the encryption system AES. The numerical results show that the encrypted images present a persistent behavior which is close to that of the 1/f-noise. These results point to the possibility that the DFA scaling exponent can be used to measure the quality of the encrypted image content.

  14. Scanning tomographic particle image velocimetry applied to a turbulent jet

    KAUST Repository

    Casey, T. A.; Sakakibara, J.; Thoroddsen, Sigurdur T

    2013-01-01

    planes in the depth direction by maintaining optimal particle image density and limiting the number of ghost particles. The total measurement volumes contain between 1 ×106 and 3 ×106 velocity vectors calculated from up to 1500 reconstructed depthwise

  15. Upconversion applied for mid-IR hyperspectral image acquisition

    DEFF Research Database (Denmark)

    Tidemand-Lichtenberg, Peter; Kehlet, Louis Martinus; Sanders, Nicolai Højer

    2015-01-01

    Different schemes for upconversion mid-IR hyperspectral imaging is implemented and compared in terms of spectral coverage, spectral resolution, speed and noise. Phasematch scanning and scanning of the object within the field of view is considered....

  16. Coding aperture applied to X-ray imaging

    International Nuclear Information System (INIS)

    Brunol, J.; Sauneuf, R.; Gex, J.P.

    1980-05-01

    We present some X-ray images of grids and plasmas. These images were obtained by using a single circular slit (annular code) as coding aperture and a computer decoding process. The experimental resolution is better than 10μm and it is expected to be in the order of 2 or 3 μm with the same code and an improved decoding process

  17. Detecting crack profile in concrete using digital image correlation and acoustic emission

    Directory of Open Access Journals (Sweden)

    Loukili A.

    2010-06-01

    Full Text Available Failure process in concrete structures is usually accompanied by cracking of concrete. Understanding the cracking pattern is very important while studying the failure governing criteria of concrete. The cracking phenomenon in concrete structures is usually complex and involves many microscopic mechanisms caused by material heterogeneity. Since last many years, fracture or damage analysis by experimental examinations of the cement based composites has shown importance to evaluate the cracking and damage behavior of those heterogeneous materials with damage accumulation due to microcracks development ahead of the propagating crack tip; and energy dissipation resulted during the evolution of damage in the structure. The techniques used in those experiments may be the holographic interferometry, the dye penetration, the scanning electron microscopy, the acoustic emission etc. Those methods offer either the images of the material surface to observe micro-features of the concrete with qualitative analysis, or the black-white fringe patterns of the deformation on the specimen surface, from which it is difficult to observe profiles of the damaged materials.

  18. Testicular microlithiasis and preliminary experience of acoustic radiation force impulse imaging

    International Nuclear Information System (INIS)

    Pedersen, Malene Roland; Osther, Palle Jørn Sloth; Rafaelsen, Søren Rafael

    2016-01-01

    Elastography of the testis can be used as a part of multiparametric examination of the scrotum. To determine the testicular stiffness using acoustic radiation force impulse imaging (ARFI) technique in men with testicular microlithiasis (TML). In 2013, 12 patients with diagnosed testicular microlithiasis in 2008 (mean age, 51 years; age range, 25–76 years) underwent a 5-year follow-up B-mode ultrasonography with three ARFI elastography measurements of each testis. We used a Siemens Acuson S3000 machine. No malignancy was found at the 5-year follow-up B-mode and elastography in 2013. However, we found an increase in TML; in the previous ultrasonography in 2008, eight men had bilateral TML, whereas in 2013, 10 men were diagnosed with bilateral TML. The mean elasticity of testicles with TML was 0.82 m/s (interquartile range [IQR], 0.72–0.88 m/s; range, 65–1.08 m/s). Elastography velocity of testis with TML seems to be in the same velocity range as in men with normal testis tissue

  19. Development and validation of a combined phased acoustical radiosity and image source model for predicting sound fields in rooms.

    Science.gov (United States)

    Marbjerg, Gerd; Brunskog, Jonas; Jeong, Cheol-Ho; Nilsson, Erling

    2015-09-01

    A model, combining acoustical radiosity and the image source method, including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Method (PARISM), and it has been developed in order to be able to model both specular and diffuse reflections with complex-valued and angle-dependent boundary conditions. This paper mainly describes the combination of the two models and the implementation of the angle-dependent boundary conditions. It furthermore describes how a pressure impulse response is obtained from the energy-based acoustical radiosity by regarding the model as being stochastic. Three methods of implementation are proposed and investigated, and finally, recommendations are made for their use. Validation of the image source method is done by comparison with finite element simulations of a rectangular room with a porous absorber ceiling. Results from the full model are compared with results from other simulation tools and with measurements. The comparisons of the full model are done for real-valued and angle-independent surface properties. The proposed model agrees well with both the measured results and the alternative theories, and furthermore shows a more realistic spatial variation than energy-based methods due to the fact that interference is considered.

  20. Performance evaluation of the EM algorithm applied to radiographic images

    International Nuclear Information System (INIS)

    Brailean, J.C.; Giger, M.L.; Chen, C.T.; Sullivan, B.J.

    1990-01-01

    In this paper the authors evaluate the expectation maximization (EM) algorithm, both qualitatively and quantitatively, as a technique for enhancing radiographic images. Previous studies have qualitatively shown the usefulness of the EM algorithm but have failed to quantify and compare its performance with those of other image processing techniques. Recent studies by Loo et al, Ishida et al, and Giger et al, have explained improvements in image quality quantitatively in terms of a signal-to-noise ratio (SNR) derived from signal detection theory. In this study, we take a similar approach in quantifying the effect of the EM algorithm on detection of simulated low-contrast square objects superimposed on radiographic mottle. The SNRs of the original and processed images are calculated taking into account both the human visual system response and the screen-film transfer function as well as a noise component internal to the eye-brain system. The EM algorithm was also implemented on digital screen-film images of test patterns and clinical mammograms

  1. Quality assessment of butter cookies applying multispectral imaging

    Science.gov (United States)

    Andresen, Mette S; Dissing, Bjørn S; Løje, Hanne

    2013-01-01

    A method for characterization of butter cookie quality by assessing the surface browning and water content using multispectral images is presented. Based on evaluations of the browning of butter cookies, cookies were manually divided into groups. From this categorization, reference values were calculated for a statistical prediction model correlating multispectral images with a browning score. The browning score is calculated as a function of oven temperature and baking time. It is presented as a quadratic response surface. The investigated process window was the intervals 4–16 min and 160–200°C in a forced convection electrically heated oven. In addition to the browning score, a model for predicting the average water content based on the same images is presented. This shows how multispectral images of butter cookies may be used for the assessment of different quality parameters. Statistical analysis showed that the most significant wavelengths for browning predictions were in the interval 400–700 nm and the wavelengths significant for water prediction were primarily located in the near-infrared spectrum. The water prediction model was found to correctly estimate the average water content with an absolute error of 0.22%. From the images it was also possible to follow the browning and drying propagation from the cookie edge toward the center. PMID:24804036

  2. A simulation technique for 3D MR-guided acoustic radiation force imaging

    International Nuclear Information System (INIS)

    Payne, Allison; Bever, Josh de; Farrer, Alexis; Coats, Brittany; Parker, Dennis L.; Christensen, Douglas A.

    2015-01-01

    Purpose: In magnetic resonance-guided focused ultrasound (MRgFUS) therapies, the in situ characterization of the focal spot location and quality is critical. MR acoustic radiation force imaging (MR-ARFI) is a technique that measures the tissue displacement caused by the radiation force exerted by the ultrasound beam. This work presents a new technique to model the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model. Methods: When a steady-state point-source force acts internally in an infinite homogeneous medium, the displacement of the material in all directions is given by the Somigliana elastostatic tensor. The radiation force field, which is caused by absorption and reflection of the incident ultrasound intensity pattern, will be spatially distributed, and the tensor formulation takes the form of a convolution of a 3D Green’s function with the force field. The dynamic accumulation of MR phase during the ultrasound pulse can be theoretically accounted for through a time-of-arrival weighting of the Green’s function. This theoretical model was evaluated experimentally in gelatin phantoms of varied stiffness (125-, 175-, and 250-bloom). The acoustic and mechanical properties of the phantoms used as parameters of the model were measured using independent techniques. Displacements at focal depths of 30- and 45-mm in the phantoms were measured by a 3D spin echo MR-ARFI segmented-EPI sequence. Results: The simulated displacements agreed with the MR-ARFI measured displacements for all bloom values and focal depths with a normalized RMS difference of 0.055 (range 0.028–0.12). The displacement magnitude decreased and the displacement pattern broadened with increased bloom value for both focal depths, as predicted by the theory. Conclusions: A new technique that models the displacements caused by the radiation force of an ultrasound beam in a homogeneous tissue model theory has been rigorously validated through comparison

  3. Personal Computer (PC) based image processing applied to fluid mechanics

    Science.gov (United States)

    Cho, Y.-C.; Mclachlan, B. G.

    1987-01-01

    A PC based image processing system was employed to determine the instantaneous velocity field of a two-dimensional unsteady flow. The flow was visualized using a suspension of seeding particles in water, and a laser sheet for illumination. With a finite time exposure, the particle motion was captured on a photograph as a pattern of streaks. The streak pattern was digitized and processed using various imaging operations, including contrast manipulation, noise cleaning, filtering, statistical differencing, and thresholding. Information concerning the velocity was extracted from the enhanced image by measuring the length and orientation of the individual streaks. The fluid velocities deduced from the randomly distributed particle streaks were interpolated to obtain velocities at uniform grid points. For the interpolation a simple convolution technique with an adaptive Gaussian window was used. The results are compared with a numerical prediction by a Navier-Stokes computation.

  4. A new deconvolution method applied to ultrasonic images

    International Nuclear Information System (INIS)

    Sallard, J.

    1999-01-01

    This dissertation presents the development of a new method for restoration of ultrasonic signals. Our goal is to remove the perturbations induced by the ultrasonic probe and to help to characterize the defects due to a strong local discontinuity of the acoustic impedance. The point of view adopted consists in taking into account the physical properties in the signal processing to develop an algorithm which gives good results even on experimental data. The received ultrasonic signal is modeled as a convolution between a function that represents the waveform emitted by the transducer and a function that is abusively called the 'defect impulse response'. It is established that, in numerous cases, the ultrasonic signal can be expressed as a sum of weighted, phase-shifted replicas of a reference signal. Deconvolution is an ill-posed problem. A priori information must be taken into account to solve the problem. The a priori information translates the physical properties of the ultrasonic signals. The defect impulse response is modeled as a Double-Bernoulli-Gaussian sequence. Deconvolution becomes the problem of detection of the optimal Bernoulli sequence and estimation of the associated complex amplitudes. Optimal parameters of the sequence are those which maximize a likelihood function. We develop a new estimation procedure based on an optimization process. An adapted initialization procedure and an iterative algorithm enables to quickly process a huge number of data. Many experimental ultrasonic data that reflect usual control configurations have been processed and the results demonstrate the robustness of the method. Our algorithm enables not only to remove the waveform emitted by the transducer but also to estimate the phase. This parameter is useful for defect characterization. At last the algorithm makes easier data interpretation by concentrating information. So automatic characterization should be possible in the future. (author)

  5. Quality assessment of butter cookies applying multispectral imaging

    DEFF Research Database (Denmark)

    Stenby Andresen, Mette; Dissing, Bjørn Skovlund; Løje, Hanne

    2013-01-01

    calculated for a statistical prediction model correlating multispectral images with a browning score. The browning score is calculated as a function of oven temperature and baking time. It is presented as a quadratic response surface. The investigated process window was the intervals 4–16 min and 160–200°C...

  6. Acoustics an introduction

    CERN Document Server

    Kuttruff, Heinrich

    2006-01-01

    This definitive textbook provides students with a comprehensive introduction to acoustics. Beginning with the basic physical ideas, Acoustics balances the fundamentals with engineering aspects, applications and electroacoustics, also covering music, speech and the properties of human hearing. The concepts of acoustics are exposed and applied in:room acousticssound insulation in buildingsnoise controlunderwater sound and ultrasoundScientifically thorough, but with mathematics kept to a minimum, Acoustics is the perfect introduction to acoustics for students at any level of mechanical, electrical or civil engineering courses and an accessible resource for architects, musicians or sound engineers requiring a technical understanding of acoustics and their applications.

  7. Scanning tomographic particle image velocimetry applied to a turbulent jet

    KAUST Repository

    Casey, T. A.

    2013-02-21

    We introduce a modified tomographic PIV technique using four high-speed video cameras and a scanning pulsed laser-volume. By rapidly illuminating adjacent subvolumes onto separate video frames, we can resolve a larger total volume of velocity vectors, while retaining good spatial resolution. We demonstrate this technique by performing time-resolved measurements of the turbulent structure of a round jet, using up to 9 adjacent volume slices. In essence this technique resolves more velocity planes in the depth direction by maintaining optimal particle image density and limiting the number of ghost particles. The total measurement volumes contain between 1 ×106 and 3 ×106 velocity vectors calculated from up to 1500 reconstructed depthwise image planes, showing time-resolved evolution of the large-scale vortical structures for a turbulent jet of Re up to 10 000.

  8. Content-based image retrieval applied to bone age assessment

    Science.gov (United States)

    Fischer, Benedikt; Brosig, André; Welter, Petra; Grouls, Christoph; Günther, Rolf W.; Deserno, Thomas M.

    2010-03-01

    Radiological bone age assessment is based on local image regions of interest (ROI), such as the epiphysis or the area of carpal bones. These are compared to a standardized reference and scores determining the skeletal maturity are calculated. For computer-aided diagnosis, automatic ROI extraction and analysis is done so far mainly by heuristic approaches. Due to high variations in the imaged biological material and differences in age, gender and ethnic origin, automatic analysis is difficult and frequently requires manual interactions. On the contrary, epiphyseal regions (eROIs) can be compared to previous cases with known age by content-based image retrieval (CBIR). This requires a sufficient number of cases with reliable positioning of the eROI centers. In this first approach to bone age assessment by CBIR, we conduct leaving-oneout experiments on 1,102 left hand radiographs and 15,428 metacarpal and phalangeal eROIs from the USC hand atlas. The similarity of the eROIs is assessed by cross-correlation of 16x16 scaled eROIs. The effects of the number of eROIs, two age computation methods as well as the number of considered CBIR references are analyzed. The best results yield an error rate of 1.16 years and a standard deviation of 0.85 years. As the appearance of the hand varies naturally by up to two years, these results clearly demonstrate the applicability of the CBIR approach for bone age estimation.

  9. Contribution to automatic image recognition applied to robot technology

    International Nuclear Information System (INIS)

    Juvin, Didier

    1983-01-01

    This paper describes a method for the analysis and interpretation of the images of objects located in a plain scene which is the environment of a robot. The first part covers the recovery of the contour of objects present in the image, and discusses a novel contour-following technique based on the line arborescence concept in combination with a 'cost function' giving a quantitative assessment of contour quality. We present heuristics for moderate-cost, minimum-time arborescence coverage, which is equivalent to following probable contour lines in the image. A contour segmentation technique, invariant in the translational and rotational modes, is presented next. The second part describes a recognition method based on the above invariant encoding: the algorithm performs a preliminary screening based on coarse data derived from segmentation, followed by a comparison of forms with probable identity through application of a distance specified in terms of the invariant encoding. The last part covers the outcome of the above investigations, which have found an industrial application in the vision system of a range of robots. The system is set up in a 16-bit microprocessor and operates in real time. (author) [fr

  10. Seeing Sound - Image Analysis of the Lift-off Acoustic Field, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — A launch vehicle and its launch facilities are subjected to intense acoustic loads generated by the vehicle's propulsion system. The vehicle, its payload, and...

  11. An acoustic pyrometer system for tomographic thermal imaging in power plant boilers

    OpenAIRE

    Bramanti, Mauro; Gray, Antoinia; Pasini, Sauro; Salerno, Emanuele; Tonazzini, Anna

    1994-01-01

    The paper presents an acoustic pyrometry method for the reconstruction of temperature maps inside power plant boilers. It is based on measuring times-of-flight of acoustic waves along a number of straight paths in a cross-section of the boiler; via an integral relationship, these times depend on the temperature of the gaseous medium along the paths. On this basis, 2D temperature maps can be reconstructed using" suitable inversion techniques. The structure of a particular 'system for the measu...

  12. Acoustic tomography and 3-D resistivity imaging of grout filled waste cells

    International Nuclear Information System (INIS)

    Morgan, F.D.; Chauvelier, C.; Shi, Weiqun; Lesmes, D.

    1997-01-01

    The Scientific Ecology Group, Inc., (SEG) was contracted by Martin Marietta Energy Systems, Inc., to demonstrate and evaluate four grout compounds for use in stabilizing radioactive waste trenches at the Oak Ridge National Laboratory (ORNL). The demonstration site was constructed at SEG's Gallaher Road test facility in Kingston, Tennessee. SEG's objectives in this project were to compare the effectiveness of the candidate grouts and grouting procedures to hydrologically isolate the waste contained within the trenches and to stabilize the trenches against subsequent subsidence. In a separate agreement with Martin Marietta Energy Systems, MIT was contracted to demonstrate the feasibility of using high-frequency acoustic tomographic imaging to evaluate the performance of the various grouts and grouting procedures, and to monitor the stability of the grouted test cells over time. The test trench consisted of four contiguous cells, each 14 feet long x 12 feet wide x 12 feet deep. The native soil in which the test cells were constructed consisted of fine red clay which is typical of the Oak Ridge area. A plan view of the test cells is shown in Figure 1 , and a cross-sectional view of one of the cells within the trench. Each cell within the trench was filled with approximately 75 cubic yards of simulated waste. The simulated waste, which included 55 gallon drums and HEPA filters, consisted of approximately 35% metal, 15% wood, and 50% paper/plastic. After the cells were loaded with the simulated waste, the trench was covered by three feet of soil to grade, to duplicate the trench configuration commonly found at ORNL

  13. Decision theory applied to image quality control in radiology.

    Science.gov (United States)

    Lessa, Patrícia S; Caous, Cristofer A; Arantes, Paula R; Amaro, Edson; de Souza, Fernando M Campello

    2008-11-13

    The present work aims at the application of the decision theory to radiological image quality control (QC) in diagnostic routine. The main problem addressed in the framework of decision theory is to accept or reject a film lot of a radiology service. The probability of each decision of a determined set of variables was obtained from the selected films. Based on a radiology service routine a decision probability function was determined for each considered group of combination characteristics. These characteristics were related to the film quality control. These parameters were also framed in a set of 8 possibilities, resulting in 256 possible decision rules. In order to determine a general utility application function to access the decision risk, we have used a simple unique parameter called r. The payoffs chosen were: diagnostic's result (correct/incorrect), cost (high/low), and patient satisfaction (yes/no) resulting in eight possible combinations. Depending on the value of r, more or less risk will occur related to the decision-making. The utility function was evaluated in order to determine the probability of a decision. The decision was made with patients or administrators' opinions from a radiology service center. The model is a formal quantitative approach to make a decision related to the medical imaging quality, providing an instrument to discriminate what is really necessary to accept or reject a film or a film lot. The method presented herein can help to access the risk level of an incorrect radiological diagnosis decision.

  14. Automated microaneurysm detection algorithms applied to diabetic retinopathy retinal images

    Directory of Open Access Journals (Sweden)

    Akara Sopharak

    2013-07-01

    Full Text Available Diabetic retinopathy is the commonest cause of blindness in working age people. It is characterised and graded by the development of retinal microaneurysms, haemorrhages and exudates. The damage caused by diabetic retinopathy can be prevented if it is treated in its early stages. Therefore, automated early detection can limit the severity of the disease, improve the follow-up management of diabetic patients and assist ophthalmologists in investigating and treating the disease more efficiently. This review focuses on microaneurysm detection as the earliest clinically localised characteristic of diabetic retinopathy, a frequently observed complication in both Type 1 and Type 2 diabetes. Algorithms used for microaneurysm detection from retinal images are reviewed. A number of features used to extract microaneurysm are summarised. Furthermore, a comparative analysis of reported methods used to automatically detect microaneurysms is presented and discussed. The performance of methods and their complexity are also discussed.

  15. Apparatus for real-time acoustic imaging of Rayleigh-Bénard convection

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, Kerry, K.

    2008-10-28

    We have successfully designed, built and tested an experimental apparatus which is capable of providing the first real-time ultrasound images of Rayleigh-B\\'{e}nard convection in optically opaque fluids confined to large aspect ratio experimental cells. The apparatus employs a modified version of a commercially available ultrasound camera to capture images (30 frames per second) of flow patterns in a fluid undergoing Rayleigh Bénard convection. The apparatus was validated by observing convection rolls in 5cSt polydimethylsiloxane (PDMS) polymer fluid. Our first objective, after having built the apparatus, was to use it to study the sequence of transitions from diffusive to time--dependent heat transport in liquid mercury. The aim was to provide important information on pattern formation in the largely unexplored regime of very low Prandtl number fluids. Based on the theoretical stability diagram for liquid mercury, we anticipated that straight rolls should be stable over a range of Rayleigh numbers, between 1708 and approximately 1900. Though some of our power spectral densities were suggestive of the existence of weak convection, we have been unable to unambiguously visualize stable convection rolls above the theoretical onset of convection in liquid mercury. Currently, we are seeking ways to increase the sensitivity of our apparatus, such as (i) improving the acoustic impedance matching between our materials in the ultrasound path and (ii) reducing the noise level in our acoustic images due to turbulence and cavitation in the cooling fluids circulating above and below our experimental cell. If we are able to convincingly improve the sensitivity of our apparatus, and we still do not observe stable convection rolls in liquid mercury, then it may be the case that the theoretical stability diagram requires revision. In that case, either (i) straight rolls are not stable in a large aspect ratio cell at the Prandtl numbers associated with liquid mercury, or (ii

  16. The use of Acoustic Radiation Force decorrelation-weighted pulse inversion (ADW-PI) for enhanced ultrasound contrast imaging

    Science.gov (United States)

    Herbst, Elizabeth; Unnikrishnan, Sunil; Wang, Shiying; Klibanov, Alexander L.; Hossack, John A.; Mauldin, F. William

    2016-01-01

    Objectives The use of ultrasound imaging for cancer diagnosis and screening can be enhanced with the use of molecularly targeted microbubbles. Nonlinear imaging strategies such as pulse inversion (PI) and “contrast pulse sequences” (CPS) can be used to differentiate microbubble signal, but often fail to suppress highly echogenic tissue interfaces. This failure results in false positive detection and potential misdiagnosis. In this study, a novel Acoustic Radiation Force (ARF) based approach was developed for superior microbubble signal detection. The feasibility of this technique, termed ARF-decorrelation-weighted PI (ADW-PI), was demonstrated in vivo using a subcutaneous mouse tumor model. Materials and Methods Tumors were implanted in the hindlimb of C57BL/6 mice by subcutaneous injection of MC38 cells. Lipid-shelled microbubbles were conjugated to anti-VEGFR2 antibody and administered via bolus injection. An image sequence using ARF pulses to generate microbubble motion was combined with PI imaging on a Verasonics Vantage programmable scanner. ADW-PI images were generated by combining PI images with inter-frame signal decorrelation data. For comparison, CPS images of the same mouse tumor were acquired using a Siemens Sequoia clinical scanner. Results Microbubble-bound regions in the tumor interior exhibited significantly higher signal decorrelation than static tissue (n = 9, p < 0.001). The application of ARF significantly increased microbubble signal decorrelation (n = 9, p < 0.01). Using these decorrelation measurements, ADW-PI imaging demonstrated significantly improved microbubble contrast-to-tissue ratio (CTR) when compared to corresponding CPS or PI images (n = 9, p < 0.001). CTR improved with ADW-PI by approximately 3 dB compared to PI images and 2 dB compared to CPS images. Conclusions Acoustic radiation force can be used to generate adherent microbubble signal decorrelation without microbubble bursting. When combined with pulse inversion

  17. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. NDE of friction stir welds, nonlinear acoustics, ultrasonic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Lingvall, Fredrik; Wennerstroem, Erik; Ping Wu [Uppsala Univ., Dept. of Materials Science (Sweden). Signals and Systems

    2004-01-01

    This report contains results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2002/2003. After a short introduction a review of the NDE techniques that have been applied to the assessment of friction stir welds (FSW) is presented. The review is based on the results reported by the specialists from the USA, mostly from the aerospace industry. A separate chapter is devoted to the extended experimental and theoretical research concerning potential of nonlinear waves in NDE applications. Further studies concerning nonlinear propagation of acoustic and elastic waves (classical nonlinearity) are reported. Also a preliminary investigation of the nonlinear ultrasonic detection of contacts and interfaces (non-classical nonlinearity) is included. Report on the continuation of previous work concerning computer simulation of nonlinear propagations of ultrasonic beams in water and in immersed solids is also presented. Finally, results of an investigation concerning a new method of synthetic aperture imaging (SAI) and its comparison to the traditional phased array (PA) imaging and to the synthetic aperture focusing technique (SAFT) are presented. A new spatial-temporal filtering method is presented that is a generalization of the previously proposed filter. Spatial resolution of the proposed method is investigated and compared experimentally to that of classical SAFT and PA imaging. Performance of the proposed method for flat targets is also investigated.

  18. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. NDE of friction stir welds, nonlinear acoustics, ultrasonic imaging

    International Nuclear Information System (INIS)

    Stepinski, Tadeusz; Lingvall, Fredrik; Wennerstroem, Erik; Ping Wu

    2004-01-01

    This report contains results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2002/2003. After a short introduction a review of the NDE techniques that have been applied to the assessment of friction stir welds (FSW) is presented. The review is based on the results reported by the specialists from the USA, mostly from the aerospace industry. A separate chapter is devoted to the extended experimental and theoretical research concerning potential of nonlinear waves in NDE applications. Further studies concerning nonlinear propagation of acoustic and elastic waves (classical nonlinearity) are reported. Also a preliminary investigation of the nonlinear ultrasonic detection of contacts and interfaces (non-classical nonlinearity) is included. Report on the continuation of previous work concerning computer simulation of nonlinear propagations of ultrasonic beams in water and in immersed solids is also presented. Finally, results of an investigation concerning a new method of synthetic aperture imaging (SAI) and its comparison to the traditional phased array (PA) imaging and to the synthetic aperture focusing technique (SAFT) are presented. A new spatial-temporal filtering method is presented that is a generalization of the previously proposed filter. Spatial resolution of the proposed method is investigated and compared experimentally to that of classical SAFT and PA imaging. Performance of the proposed method for flat targets is also investigated

  19. Monitoring of pipeline hydrostatic testing with artificial flaws applying acoustic emission and ultra-sonic techniques; Monitoracao de teste hidrostatico de tubos com descontinuidades artificiais empregando as tecnicas de emissao acustica e ultra-som

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Sergio Damasceno [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2003-07-01

    Charts and parameters used to perform and analyzing the acoustic emission data collected during the hydrostatic test in pipe samples build in API XL 60 with 20 inches of diameter and 14 millimeters of thickness are shown. These pipes had internal and external artificial flaws done by electro-erosion process with aspect ratio 1 x 20. A relationship between acoustic emission results, ultrasound and J-Integral were established using the applied pressurization sequence. Characteristics values of acoustic emission signals were shown as a criteria of field tests. (author)

  20. Enlarged acceptance angle of a finite size detector in photoacoustic imaging using acoustic lenses

    NARCIS (Netherlands)

    Xia, W.; Piras, D.; Heijblom, Michelle; van Hespen, Johannes C.G.; Steenbergen, Wiendelt; Manohar, Srirang; van Veldhoven, Spiridon; Prins, Christian; van Leeuwen, Ton

    2011-01-01

    A large surface area transducer is preferable to be used to detect extremely weak photoacoustic signals in mammography due to its high sensitivity. The lateral resolution is limited by the small acceptance angle of such a transducer. We introduce an excellent material for an acoustic lens used to

  1. Applying and extending ISO/TC42 digital camera resolution standards to mobile imaging products

    Science.gov (United States)

    Williams, Don; Burns, Peter D.

    2007-01-01

    There are no fundamental differences between today's mobile telephone cameras and consumer digital still cameras that suggest many existing ISO imaging performance standards do not apply. To the extent that they have lenses, color filter arrays, detectors, apertures, image processing, and are hand held, there really are no operational or architectural differences. Despite this, there are currently differences in the levels of imaging performance. These are driven by physical and economic constraints, and image-capture conditions. Several ISO standards for resolution, well established for digital consumer digital cameras, require care when applied to the current generation of cell phone cameras. In particular, accommodation of optical flare, shading non-uniformity and distortion are recommended. We offer proposals for the application of existing ISO imaging resolution performance standards to mobile imaging products, and suggestions for extending performance standards to the characteristic behavior of camera phones.

  2. Simultaneous observation of cavitation bubbles generated in biological tissue by high-speed optical and acoustic imaging methods

    Science.gov (United States)

    Suzuki, Kai; Iwasaki, Ryosuke; Takagi, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

    2017-07-01

    Acoustic cavitation bubbles are useful for enhancing the heating effect in high-intensity focused ultrasound (HIFU) treatment. Many studies were conducted to investigate the behavior of such bubbles in tissue-mimicking materials, such as a transparent gel phantom; however, the detailed behavior in tissue was still unclear owing to the difficulty in optical observation. In this study, a new biological phantom was developed to observe cavitation bubbles generated in an optically shallow area of tissue. Two imaging methods, high-speed photography using light scattering and high-speed ultrasonic imaging, were used for detecting the behavior of the bubbles simultaneously. The results agreed well with each other for the area of bubble formation and the temporal change in the region of bubbles, suggesting that both methods are useful for visualizing the bubbles.

  3. Status of thermal imaging technology as applied to conservation-update 1

    Energy Technology Data Exchange (ETDEWEB)

    Snow, F.J.; Wood, J.T.; Barthle, R.C.

    1980-07-01

    This document updates the 1978 report on the status of thermal imaging technology as applied to energy conservation in buildings. Thermal imaging technology is discussed in terms of airborne surveys, ground survey programs, and application needs such as standards development and lower cost equipment. Information on the various thermal imaging devices was obtained from manufacturer's standard product literature. Listings are provided of infrared projects of the DOE building diagnostics program, of aerial thermographic firms, and of aerial survey programs. (LCL)

  4. A study on the application of two different acoustic analogies to experimental PIV data

    NARCIS (Netherlands)

    Koschatzky, V.; Westerweel, J.; Boersma, B.J.

    2011-01-01

    The aim of the present study is to compare two different acoustic analogies applied to time-resolved particle image velocimetry (PIV) data for the prediction of the acoustic far-field generated by the flow over a rectangular cavity. We consider the model problem of sound radiating from an open,

  5. GPU-based Green's function simulations of shear waves generated by an applied acoustic radiation force in elastic and viscoelastic models.

    Science.gov (United States)

    Yang, Yiqun; Urban, Matthew W; McGough, Robert J

    2018-05-15

    Shear wave calculations induced by an acoustic radiation force are very time-consuming on desktop computers, and high-performance graphics processing units (GPUs) achieve dramatic reductions in the computation time for these simulations. The acoustic radiation force is calculated using the fast near field method and the angular spectrum approach, and then the shear waves are calculated in parallel with Green's functions on a GPU. This combination enables rapid evaluation of shear waves for push beams with different spatial samplings and for apertures with different f/#. Relative to shear wave simulations that evaluate the same algorithm on an Intel i7 desktop computer, a high performance nVidia GPU reduces the time required for these calculations by a factor of 45 and 700 when applied to elastic and viscoelastic shear wave simulation models, respectively. These GPU-accelerated simulations also compared to measurements in different viscoelastic phantoms, and the results are similar. For parametric evaluations and for comparisons with measured shear wave data, shear wave simulations with the Green's function approach are ideally suited for high-performance GPUs.

  6. GPU-based Green’s function simulations of shear waves generated by an applied acoustic radiation force in elastic and viscoelastic models

    Science.gov (United States)

    Yang, Yiqun; Urban, Matthew W.; McGough, Robert J.

    2018-05-01

    Shear wave calculations induced by an acoustic radiation force are very time-consuming on desktop computers, and high-performance graphics processing units (GPUs) achieve dramatic reductions in the computation time for these simulations. The acoustic radiation force is calculated using the fast near field method and the angular spectrum approach, and then the shear waves are calculated in parallel with Green’s functions on a GPU. This combination enables rapid evaluation of shear waves for push beams with different spatial samplings and for apertures with different f/#. Relative to shear wave simulations that evaluate the same algorithm on an Intel i7 desktop computer, a high performance nVidia GPU reduces the time required for these calculations by a factor of 45 and 700 when applied to elastic and viscoelastic shear wave simulation models, respectively. These GPU-accelerated simulations also compared to measurements in different viscoelastic phantoms, and the results are similar. For parametric evaluations and for comparisons with measured shear wave data, shear wave simulations with the Green’s function approach are ideally suited for high-performance GPUs.

  7. Evidence from acoustic imaging for submarine volcanic activity in 2012 off the west coast of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen

    2014-12-01

    We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge

  8. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Nonlinear acoustics, synthetic aperture imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lingvall, Fredrik; Ping Wu; Stepinski, Tadeusz [Uppsala Univ., (Sweden). Dept. of Materials Science

    2003-03-01

    This report contains results concerning inspection of copper canisters for spent nuclear fuel by means of ultrasound obtained at Signals and Systems, Uppsala University in year 2001/2002. The first chapter presents results of an investigation of a new method for synthetic aperture imaging. The new method presented here takes the form of a 2D filter based on minimum mean squared error (MMSE) criteria. The filter, which varies with the target position in two dimensions includes information about spatial impulse response (SIR) of the imaging system. Spatial resolution of the MMSE method is investigated and compared experimentally to that of the classical SAFT and phased array imaging. It is shown that the resolution of the MMSE algorithm, evaluated for imaging immersed copper specimen is superior to that observed for the two above-mentioned methods. Extended experimental and theoretical research concerning the potential of nonlinear waves and material harmonic imaging is presented in the second chapter. An experimental work is presented that was conducted using the RITEC RAM-5000 ultrasonic system capable of providing a high power tone-burst output. A new method for simulation of nonlinear acoustic waves that is a combination of the angular spectrum approach and the Burger's equation is also presented. This method was used for simulating nonlinear elastic waves radiated by the annular transducer that was used in the experiments.

  9. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Nonlinear acoustics, synthetic aperture imaging

    International Nuclear Information System (INIS)

    Lingvall, Fredrik; Ping Wu; Stepinski, Tadeusz

    2003-03-01

    This report contains results concerning inspection of copper canisters for spent nuclear fuel by means of ultrasound obtained at Signals and Systems, Uppsala University in year 2001/2002. The first chapter presents results of an investigation of a new method for synthetic aperture imaging. The new method presented here takes the form of a 2D filter based on minimum mean squared error (MMSE) criteria. The filter, which varies with the target position in two dimensions includes information about spatial impulse response (SIR) of the imaging system. Spatial resolution of the MMSE method is investigated and compared experimentally to that of the classical SAFT and phased array imaging. It is shown that the resolution of the MMSE algorithm, evaluated for imaging immersed copper specimen is superior to that observed for the two above-mentioned methods. Extended experimental and theoretical research concerning the potential of nonlinear waves and material harmonic imaging is presented in the second chapter. An experimental work is presented that was conducted using the RITEC RAM-5000 ultrasonic system capable of providing a high power tone-burst output. A new method for simulation of nonlinear acoustic waves that is a combination of the angular spectrum approach and the Burger's equation is also presented. This method was used for simulating nonlinear elastic waves radiated by the annular transducer that was used in the experiments

  10. The Acoustic Lens Design and in Vivo Use of a Multifunctional Catheter Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    Science.gov (United States)

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Sahn, David

    2009-01-01

    A multifunctional 9F intracardiac imaging and electrophysiology mapping catheter was developed and tested to help guide diagnostic and therapeutic intracardiac electrophysiology (EP) procedures. The catheter tip includes a 7.25-MHz, 64-element, side-looking phased array for high resolution sector scanning. Multiple electrophysiology mapping sensors were mounted as ring electrodes near the array for electrocardiographic synchronization of ultrasound images. The catheter array elevation beam performance in particular was investigated. An acoustic lens for the distal tip array designed with a round cross section can produce an acceptable elevation beam shape; however, the velocity of sound in the lens material should be approximately 155 m/s slower than in tissue for the best beam shape and wide bandwidth performance. To help establish the catheter’s unique ability for integration with electrophysiology interventional procedures, it was used in vivo in a porcine animal model, and demonstrated both useful intracardiac echocardiographic visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheter also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. PMID:18407850

  11. Towards factor analysis exploration applied to positron emission tomography functional imaging for breast cancer characterization

    International Nuclear Information System (INIS)

    Rekik, W.; Ketata, I.; Sellami, L.; Ben slima, M.; Ben Hamida, A.; Chtourou, K.; Ruan, S.

    2011-01-01

    This paper aims to explore the factor analysis when applied to a dynamic sequence of medical images obtained using nuclear imaging modality, Positron Emission Tomography (PET). This latter modality allows obtaining information on physiological phenomena, through the examination of radiotracer evolution during time. Factor analysis of dynamic medical images sequence (FADMIS) estimates the underlying fundamental spatial distributions by factor images and the associated so-called fundamental functions (describing the signal variations) by factors. This method is based on an orthogonal analysis followed by an oblique analysis. The results of the FADMIS are physiological curves showing the evolution during time of radiotracer within homogeneous tissues distributions. This functional analysis of dynamic nuclear medical images is considered to be very efficient for cancer diagnostics. In fact, it could be applied for cancer characterization, vascularization as well as possible evaluation of response to therapy.

  12. Radiation acoustics and its applications

    International Nuclear Information System (INIS)

    Lyamshev, L.M.

    1992-01-01

    Radiation acoustics is a new branch of acoustics, developing on the boundary of acoustics, nuclear physics, elementary particles and high-energy physics. Its fundamentals are laying in the research of acoustical effects due to the interaction of penetrating radiation with matter. The study of radiation-acoustical effects leads to the new opportunities in the penetration radiation research (acoustical detection, radiation-acoustical dosimetry), study of the physical parameters of matter, in a solution of some applied problems of nondestructive testing, and also for the radiation-acoustical influence on physical and chemical structure of the matter. Results of theoretical and experimental investigations are given. Different mechanisms of the sound generation by penetrating radiation of liquids and solids are considered. Some applications - the radiation acoustical microscopy and visualisation, the acoustical detection of high energy X-ray particles and possibility of using of high energy neutrino beams in geoacoustics - are discussed

  13. Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

    Directory of Open Access Journals (Sweden)

    E. Tsangouri

    2013-01-01

    Full Text Available Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

  14. Image Enhancer: A Graphic Editor to Apply Numerous Effects in Digital Image

    Directory of Open Access Journals (Sweden)

    Abhisek Hazra

    2014-12-01

    Full Text Available Image Enhancer is an open source, portable graphic editor developed for Windows platform. It is equipped with an enriched set of digital imaging filters with advanced computer vision techniques embedded within, like Interest Point Detection (Susan Corner Detector, Linear Edge Detection (Simple, Sobel, Canny, Histogram Equalization, Dithering (Bayer, Burkes, Sierra, Jarvis Judis Ninke, Transforming to Polar images and vice versa etc.  Image Enhancer was released under GNU Lesser General Public License (LGPL and the software was made available from the Microsoft’s open source project hosting repository Codeplex (http://imageenhancer.codeplex.com. Image Enhancer was tested and hosted by several popular software archives like SoftPedia, CNET, Freeware Files, ZDNet, Soft Tango and others. A stable Release Candidate (RC version has been made available in which some major modifications were done which were not present in the earlier Beta version. The download link for the Image Enhancer (both Release Candidate & Beta Version from CodePlex repository is (http://imageenhancer.codeplex.com/releases.

  15. Acoustic radiation force impulse (ARFI) ultrasound imaging of pancreatic cystic lesions

    Energy Technology Data Exchange (ETDEWEB)

    D' Onofrio, M., E-mail: mirko.donofrio@univr.it [Department of Radiology, University Hospital G.B. Rossi, Piazzale L.A. Scuro 10, University of Verona, 37134 Verona (Italy); Gallotti, A. [Department of Radiology, University Hospital G.B. Rossi, Piazzale L.A. Scuro 10, University of Verona, 37134 Verona (Italy); Salvia, R. [Department of Surgery, University Hospital G.B. Rossi, Piazzale L.A. Scuro 10, University of Verona, 37134 Verona (Italy); Capelli, P. [Department of Pathology, University Hospital G.B. Rossi, Piazzale L.A. Scuro 10, University of Verona, 37134 Verona (Italy); Mucelli, R. Pozzi [Department of Radiology, University Hospital G.B. Rossi, Piazzale L.A. Scuro 10, University of Verona, 37134 Verona (Italy)

    2011-11-15

    Purpose: To evaluate the ARFI ultrasound imaging with Virtual Touch tissue quantification in studying pancreatic cystic lesions, compared with phantom fluid models. Materials and methods: Different phantom fluids at different viscosity or density (water, iodinate contrast agent, and oil) were evaluated by two independent operators. From September to December 2008, 23 pancreatic cystic lesions were prospectively studied. All lesions were pathologically confirmed. Results: Non-numerical values on water and numerical values on other phantoms were obtained. Inter-observer evaluation revealed a perfect correlation (rs = 1.00; p < 0.0001) between all measurements achieved by both operators per each balloon and fluid. Among the pancreatic cystic lesions, 14 mucinous cystadenomas, 4 pseudocysts, 3 intraductal papillary-mucinous neoplasms and 2 serous cystadenomas were studied. The values obtained ranged from XXXX/0-4,85 m/s in mucinous cystadenomas, from XXXX/0-3,11 m/s in pseudocysts, from XXXX/0-4,57 m/s in intraductal papillary-mucinous neoplasms. In serous cystadenomas all values measured were XXXX/0 m/s. Diagnostic accuracy in benign and non-benign differentiation of pancreatic cystic lesions was 78%. Conclusions: Virtual Touch tissue quantification can be applied in the analysis of fluids and is potentially able to differentiate more complex (mucinous) from simple (serous) content in studying pancreatic cystic lesions.

  16. Acoustic radiation force impulse (ARFI) ultrasound imaging of pancreatic cystic lesions

    International Nuclear Information System (INIS)

    D'Onofrio, M.; Gallotti, A.; Salvia, R.; Capelli, P.; Mucelli, R. Pozzi

    2011-01-01

    Purpose: To evaluate the ARFI ultrasound imaging with Virtual Touch tissue quantification in studying pancreatic cystic lesions, compared with phantom fluid models. Materials and methods: Different phantom fluids at different viscosity or density (water, iodinate contrast agent, and oil) were evaluated by two independent operators. From September to December 2008, 23 pancreatic cystic lesions were prospectively studied. All lesions were pathologically confirmed. Results: Non-numerical values on water and numerical values on other phantoms were obtained. Inter-observer evaluation revealed a perfect correlation (rs = 1.00; p < 0.0001) between all measurements achieved by both operators per each balloon and fluid. Among the pancreatic cystic lesions, 14 mucinous cystadenomas, 4 pseudocysts, 3 intraductal papillary-mucinous neoplasms and 2 serous cystadenomas were studied. The values obtained ranged from XXXX/0-4,85 m/s in mucinous cystadenomas, from XXXX/0-3,11 m/s in pseudocysts, from XXXX/0-4,57 m/s in intraductal papillary-mucinous neoplasms. In serous cystadenomas all values measured were XXXX/0 m/s. Diagnostic accuracy in benign and non-benign differentiation of pancreatic cystic lesions was 78%. Conclusions: Virtual Touch tissue quantification can be applied in the analysis of fluids and is potentially able to differentiate more complex (mucinous) from simple (serous) content in studying pancreatic cystic lesions.

  17. Neural Network Blind Equalization Algorithm Applied in Medical CT Image Restoration

    Directory of Open Access Journals (Sweden)

    Yunshan Sun

    2013-01-01

    Full Text Available A new algorithm for iterative blind image restoration is presented in this paper. The method extends blind equalization found in the signal case to the image. A neural network blind equalization algorithm is derived and used in conjunction with Zigzag coding to restore the original image. As a result, the effect of PSF can be removed by using the proposed algorithm, which contributes to eliminate intersymbol interference (ISI. In order to obtain the estimation of the original image, what is proposed in this method is to optimize constant modulus blind equalization cost function applied to grayscale CT image by using conjugate gradient method. Analysis of convergence performance of the algorithm verifies the feasibility of this method theoretically; meanwhile, simulation results and performance evaluations of recent image quality metrics are provided to assess the effectiveness of the proposed method.

  18. Real-time algorithm for acoustic imaging with a microphone array.

    Science.gov (United States)

    Huang, Xun

    2009-05-01

    Acoustic phased array has become an important testing tool in aeroacoustic research, where the conventional beamforming algorithm has been adopted as a classical processing technique. The computation however has to be performed off-line due to the expensive cost. An innovative algorithm with real-time capability is proposed in this work. The algorithm is similar to a classical observer in the time domain while extended for the array processing to the frequency domain. The observer-based algorithm is beneficial mainly for its capability of operating over sampling blocks recursively. The expensive experimental time can therefore be reduced extensively since any defect in a testing can be corrected instantaneously.

  19. An electronically tunable ultrafast laser source applied to fluorescence imaging and fluorescence lifetime imaging microscopy

    International Nuclear Information System (INIS)

    Dunsby, C; Lanigan, P M P; McGinty, J; Elson, D S; Requejo-Isidro, J; Munro, I; Galletly, N; McCann, F; Treanor, B; Oenfelt, B; Davis, D M; Neil, M A A; French, P M W

    2004-01-01

    Fluorescence imaging is used widely in microscopy and macroscopic imaging applications for fields ranging from biomedicine to materials science. A critical component for any fluorescence imaging system is the excitation source. Traditionally, wide-field systems use filtered thermal or arc-generated white light sources, while point scanning confocal microscope systems require spatially coherent (point-like) laser sources. Unfortunately, the limited range of visible wavelengths available from conventional laser sources constrains the design and usefulness of fluorescent probes in confocal microscopy. A 'hands-off' laser-like source, electronically tunable across the visible spectrum, would be invaluable for fluorescence imaging and provide new opportunities, e.g. automated excitation fingerprinting and in situ measurement of excitation cross-sections. Yet more information can be obtained using fluorescence lifetime imaging (FLIM), which requires that the light source be pulsed or rapidly modulated. We show how a white light continuum, generated by injecting femtosecond optical radiation into a micro-structured optical fibre, coupled with a simple prism-based tunable filter arrangement, can fulfil all these roles as a continuously electronically tunable (435-1150 nm) visible ultrafast light source in confocal, wide-field and FLIM systems

  20. Localized Acoustic Surface Modes

    KAUST Repository

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  1. Experimental demonstration of passive acoustic imaging in the human skull cavity using CT-based aberration corrections.

    Science.gov (United States)

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

    2015-07-01

    Experimentally verify a previously described technique for performing passive acoustic imaging through an intact human skull using noninvasive, computed tomography (CT)-based aberration corrections Jones et al. [Phys. Med. Biol. 58, 4981-5005 (2013)]. A sparse hemispherical receiver array (30 cm diameter) consisting of 128 piezoceramic discs (2.5 mm diameter, 612 kHz center frequency) was used to passively listen through ex vivo human skullcaps (n = 4) to acoustic emissions from a narrow-band fixed source (1 mm diameter, 516 kHz center frequency) and from ultrasound-stimulated (5 cycle bursts, 1 Hz pulse repetition frequency, estimated in situ peak negative pressure 0.11-0.33 MPa, 306 kHz driving frequency) Definity™ microbubbles flowing through a thin-walled tube phantom. Initial in vivo feasibility testing of the method was performed. The performance of the method was assessed through comparisons to images generated without skull corrections, with invasive source-based corrections, and with water-path control images. For source locations at least 25 mm from the inner skull surface, the modified reconstruction algorithm successfully restored a single focus within the skull cavity at a location within 1.25 mm from the true position of the narrow-band source. The results obtained from imaging single bubbles are in good agreement with numerical simulations of point source emitters and the authors' previous experimental measurements using source-based skull corrections O'Reilly et al. [IEEE Trans. Biomed. Eng. 61, 1285-1294 (2014)]. In a rat model, microbubble activity was mapped through an intact human skull at pressure levels below and above the threshold for focused ultrasound-induced blood-brain barrier opening. During bursts that led to coherent bubble activity, the location of maximum intensity in images generated with CT-based skull corrections was found to deviate by less than 1 mm, on average, from the position obtained using source-based corrections. Taken

  2. Feasibility of High Frequency Acoustic Imaging for Inspection of Containments: Phase II

    International Nuclear Information System (INIS)

    Rudzinsky, J.; Bondaryk, J.; Conti, M.

    1999-01-01

    The nuclear power industry is concerned with corrosive thinning of portions of the metallic pressure boundary, particularly in areas that are not directly accessible for inspection. This study investigated the feasibility of detecting these thickness degradations using ultrasonic imaging. A commercial ultrasonic system was used to carry out several full-scale, controlled laboratory experiments. Measurements of 0.5 MHz shear wave levels propagated in 25-mm-thick steel plate embedded in concrete showed 1.4-1.6 dB of signal loss for each centimeter of two-way travel in the steel plate (compared to previous numerical predictions of 3-4 dB), and 1.3 dB of signal loss per centimeter of two-way travel in steel plates embedded in concrete prior to setting of the concrete (i.e., plastic). Negligible losses were measured in plates with a decoupling treatment applied between the steel and concrete to simulate the unbonded portions of the pressure boundary. Scattered signals from straight slots of different size and shape were investigated. The return from a 4-mm-deep rectangular slots exhibited levels 23 dB down relative to incidence and 4-6 dB higher than those obtained from both ''v'' shaped and rounded slots of similar depth. The system displayed an input/output dynamic range of 125 dB and measurement variability less than 1-2dB. Based on these results, a 4-mm-deep, rounded degradation embedded 30 cm in concrete has expected returns of -73dB relative to the input and should therefore be detectable. Results of this and a prior study indicate that the technique has merit and should be developed more fully and demonstrated in the field

  3. Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

    Science.gov (United States)

    Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

    1995-01-01

    An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

  4. Assessing hepatic fibrosis: comparing the intravoxel incoherent motion in MRI with acoustic radiation force impulse imaging in US

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chih-Horng; Liang, Po-Chin; Shih, Tiffany Ting-Fang [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); National Taiwan University College of Medicine, Department of Radiology, Taipei (China); Ho, Ming-Chih; Hu, Rey-Heng; Lai, Hong-Shiee [National Taiwan University Hospital and College of Medicine, Department of Surgery, Taipei (China); Jeng, Yung-Ming [National Taiwan University Hospital and College of Medicine, Department of Pathology, Taipei (China)

    2015-12-15

    This study compared the diagnostic performance of intravoxel incoherent motion (IVIM) in magnetic resonance imaging (MRI) and acoustic radiation force impulse imaging (ARFI) in ultrasound (US) for liver fibrosis (LF) evaluation. A total of 49 patients scheduled for liver surgery were recruited. LF in the non-tumorous liver parenchyma at the right lobe was estimated using a slow diffusion coefficient, fast diffusion coefficient (D{sub fast}), perfusion fraction (f) of the IVIM parameters, the total apparent diffusion coefficient of conventional diffusion-weighted imaging and the shear wave velocity (Vs) of ARFI. LF was graded using the Metavir scoring system on histological examination. The Spearman rank correlation coefficient for correlation and analysis of variance was used for determining difference. The diagnostic performance was compared using receiver operating characteristic curve analysis. LF exhibited significant correlation with the three parameters D{sub fast}, f, and Vs (r = -0.528, -0.337, and 0.481, respectively, P < 0.05). The D{sub fast} values in the F4 group were significantly lower than those in the F0, F1 and F2 groups. D{sub fast} exhibited a non-inferior performance for diagnosing all fibrosis grades compared with that of Vs. Both IVIM and ARFI provide reliable estimations for the noninvasive assessment of LF. (orig.)

  5. Accelerated Optical Projection Tomography Applied to In Vivo Imaging of Zebrafish.

    Directory of Open Access Journals (Sweden)

    Teresa Correia

    Full Text Available Optical projection tomography (OPT provides a non-invasive 3-D imaging modality that can be applied to longitudinal studies of live disease models, including in zebrafish. Current limitations include the requirement of a minimum number of angular projections for reconstruction of reasonable OPT images using filtered back projection (FBP, which is typically several hundred, leading to acquisition times of several minutes. It is highly desirable to decrease the number of required angular projections to decrease both the total acquisition time and the light dose to the sample. This is particularly important to enable longitudinal studies, which involve measurements of the same fish at different time points. In this work, we demonstrate that the use of an iterative algorithm to reconstruct sparsely sampled OPT data sets can provide useful 3-D images with 50 or fewer projections, thereby significantly decreasing the minimum acquisition time and light dose while maintaining image quality. A transgenic zebrafish embryo with fluorescent labelling of the vasculature was imaged to acquire densely sampled (800 projections and under-sampled data sets of transmitted and fluorescence projection images. The under-sampled OPT data sets were reconstructed using an iterative total variation-based image reconstruction algorithm and compared against FBP reconstructions of the densely sampled data sets. To illustrate the potential for quantitative analysis following rapid OPT data acquisition, a Hessian-based method was applied to automatically segment the reconstructed images to select the vasculature network. Results showed that 3-D images of the zebrafish embryo and its vasculature of sufficient visual quality for quantitative analysis can be reconstructed using the iterative algorithm from only 32 projections-achieving up to 28 times improvement in imaging speed and leading to total acquisition times of a few seconds.

  6. Photo-Acoustic Ultrasound Imaging to Distinguish Benign from Malignant Prostate Cancer

    Science.gov (United States)

    2016-09-01

    tissue phantoms and animal models of disease . 15. SUBJECT TERMS Photoacoustic, Ultrasound imaging, transurethral probe 16. SECURITY CLASSIFICATION...visible, ultrasound images are unable to discriminate between benign or malignant cancers. In photoacoustic imaging, laser energy is transmitted ...40 g/L concentration of sea plaque agarose into DI water heated to approximately 80°C. A 10 g/L concentration of silica powder was then added to

  7. Early Detection of Clinically Significant Prostate Cancer Using Ultrasonic Acoustic Radiation Force Impulse (ARFI) Imaging

    Science.gov (United States)

    2017-10-01

    Toolkit for rapid 3D visualization and image volume interpretation, followed by automated transducer positioning in a user-selected image plane for... Toolkit (IGSTK) to enable rapid 3D visualization and image volume interpretation followed by automated transducer positioning in the user-selected... careers in science, technology, and the humanities. What do you plan to do during the next reporting period to accomplish the goals? If this

  8. Joint Applied Optics and Chinese Optics Letters feature introduction: digital holography and three-dimensional imaging

    OpenAIRE

    Poon, Ting-Chung

    2011-01-01

    This feature issue serves as a pilot issue promoting the joint issue of Applied Optics and Chinese Optics Letters. It focuses upon topics of current relevance to the community working in the area of digital holography and 3-D imaging. (C) 2011 Optical Society of America

  9. Joint Applied Optics and Chinese Optics Letters feature introduction: digital holography and three-dimensional imaging.

    Science.gov (United States)

    Poon, Ting-Chung

    2011-12-01

    This feature issue serves as a pilot issue promoting the joint issue of Applied Optics and Chinese Optics Letters. It focuses upon topics of current relevance to the community working in the area of digital holography and 3-D imaging. © 2011 Optical Society of America

  10. IMAGE information monitoring and applied graphics software environment. Volume 2. Software description

    International Nuclear Information System (INIS)

    Hallam, J.W.; Ng, K.B.; Upham, G.L.

    1986-09-01

    The EPRI Information Monitoring and Applied Graphics Environment (IMAGE) system is designed for 'fast proto-typing' of advanced concepts for computer-aided plant operations tools. It is a flexible software system which can be used for rapidly creating, dynamically driving and evaluating advanced operator aid displays. The software is written to be both host computer and graphic device independent

  11. Architectural acoustics

    National Research Council Canada - National Science Library

    Long, Marshall

    2014-01-01

    .... Beginning with a brief history, it reviews the fundamentals of acoustics, human perception and reaction to sound, acoustic noise measurements, noise metrics, and environmental noise characterization...

  12. Acoustic emission

    International Nuclear Information System (INIS)

    Nichols, R.W.

    1976-01-01

    The volume contains six papers which together provide an overall review of the inspection technique known as acoustic emission or stress wave emission. The titles are: a welder's introduction to acoustic emission technology; use of acoustic emission for detection of defects as they arise during fabrication; examples of laboratory application and assessment of acoustic emission in the United Kingdom; (Part I: acoustic emission behaviour of low alloy steels; Part II: fatigue crack assessment from proof testing and continuous monitoring); inspection of selected areas of engineering structures by acoustic emission; Japanese experience in laboratory and practical applications of acoustic emission to welded structures; and ASME acoustic emission code status. (U.K.)

  13. REMOTE SENSING IMAGE CLASSIFICATION APPLIED TO THE FIRST NATIONAL GEOGRAPHICAL INFORMATION CENSUS OF CHINA

    Directory of Open Access Journals (Sweden)

    X. Yu

    2016-06-01

    Full Text Available Image classification will still be a long way in the future, although it has gone almost half a century. In fact, researchers have gained many fruits in the image classification domain, but there is still a long distance between theory and practice. However, some new methods in the artificial intelligence domain will be absorbed into the image classification domain and draw on the strength of each to offset the weakness of the other, which will open up a new prospect. Usually, networks play the role of a high-level language, as is seen in Artificial Intelligence and statistics, because networks are used to build complex model from simple components. These years, Bayesian Networks, one of probabilistic networks, are a powerful data mining technique for handling uncertainty in complex domains. In this paper, we apply Tree Augmented Naive Bayesian Networks (TAN to texture classification of High-resolution remote sensing images and put up a new method to construct the network topology structure in terms of training accuracy based on the training samples. Since 2013, China government has started the first national geographical information census project, which mainly interprets geographical information based on high-resolution remote sensing images. Therefore, this paper tries to apply Bayesian network to remote sensing image classification, in order to improve image interpretation in the first national geographical information census project. In the experiment, we choose some remote sensing images in Beijing. Experimental results demonstrate TAN outperform than Naive Bayesian Classifier (NBC and Maximum Likelihood Classification Method (MLC in the overall classification accuracy. In addition, the proposed method can reduce the workload of field workers and improve the work efficiency. Although it is time consuming, it will be an attractive and effective method for assisting office operation of image interpretation.

  14. CLOSE RANGE HYPERSPECTRAL IMAGING INTEGRATED WITH TERRESTRIAL LIDAR SCANNING APPLIED TO ROCK CHARACTERISATION AT CENTIMETRE SCALE

    Directory of Open Access Journals (Sweden)

    T. H. Kurz

    2012-07-01

    Full Text Available Compact and lightweight hyperspectral imagers allow the application of close range hyperspectral imaging with a ground based scanning setup for geological fieldwork. Using such a scanning setup, steep cliff sections and quarry walls can be scanned with a more appropriate viewing direction and a higher image resolution than from airborne and spaceborne platforms. Integration of the hyperspectral imagery with terrestrial lidar scanning provides the hyperspectral information in a georeferenced framework and enables measurement at centimetre scale. In this paper, three geological case studies are used to demonstrate the potential of this method for rock characterisation. Two case studies are applied to carbonate quarries where mapping of different limestone and dolomite types was required, as well as measurements of faults and layer thicknesses from inaccessible parts of the quarries. The third case study demonstrates the method using artificial lighting, applied in a subsurface scanning scenario where solar radiation cannot be utilised.

  15. Research in Image Understanding as Applied to 3-D Microwave Tomographic Imaging with Near Optical Resolution.

    Science.gov (United States)

    1987-03-01

    Oct. 1985. 28. D.L. Jaggard, K. Schultz, Y. Kim and P. Frangos , "Inverse Scattering for Dielectric Media", Annual OSA Meeting, Wash. D.C., Oct. 1985...T.H. Chu - Graduate Student (50%) C.Y. Ho - Graduate Student (50%) Y. Kim - Graduate Student (50%) K S. Lee - Graduate Student (50%) P. Frangos ...1982. 3. P. Frangos (Ph.D.) - "One-Dimensional Inverse Scattering: Exact Methods and Applications". 4. C.L. Werner (Ph.D.) - ŗ-D Imaging of Coherent and

  16. Image processing applied to automatic detection of defects during ultrasonic examination

    International Nuclear Information System (INIS)

    Moysan, J.

    1992-10-01

    This work is a study about image processing applied to ultrasonic BSCAN images which are obtained in the field of non destructive testing of weld. The goal is to define what image processing techniques can bring to ameliorate the exploitation of the data collected and, more precisely, what image processing can do to extract the meaningful echoes which enable to characterize and to size the defects. The report presents non destructive testing by ultrasounds in the nuclear field and it indicates specificities of the propagation of ultrasonic waves in austenitic weld. It gives a state of the art of the data processing applied to ultrasonic images in nondestructive evaluation. A new image analysis is then developed. It is based on a powerful tool, the co-occurrence matrix. This matrix enables to represent, in a whole representation, relations between amplitudes of couples of pixels. From the matrix analysis, a new complete and automatic method has been set down in order to define a threshold which separates echoes from noise. An automatic interpretation of the ultrasonic echoes is then possible. Complete validation has been done with standard pieces

  17. OPTICAL correlation identification technology applied in underwater laser imaging target identification

    Science.gov (United States)

    Yao, Guang-tao; Zhang, Xiao-hui; Ge, Wei-long

    2012-01-01

    The underwater laser imaging detection is an effective method of detecting short distance target underwater as an important complement of sonar detection. With the development of underwater laser imaging technology and underwater vehicle technology, the underwater automatic target identification has gotten more and more attention, and is a research difficulty in the area of underwater optical imaging information processing. Today, underwater automatic target identification based on optical imaging is usually realized with the method of digital circuit software programming. The algorithm realization and control of this method is very flexible. However, the optical imaging information is 2D image even 3D image, the amount of imaging processing information is abundant, so the electronic hardware with pure digital algorithm will need long identification time and is hard to meet the demands of real-time identification. If adopt computer parallel processing, the identification speed can be improved, but it will increase complexity, size and power consumption. This paper attempts to apply optical correlation identification technology to realize underwater automatic target identification. The optics correlation identification technology utilizes the Fourier transform characteristic of Fourier lens which can accomplish Fourier transform of image information in the level of nanosecond, and optical space interconnection calculation has the features of parallel, high speed, large capacity and high resolution, combines the flexibility of calculation and control of digital circuit method to realize optoelectronic hybrid identification mode. We reduce theoretical formulation of correlation identification and analyze the principle of optical correlation identification, and write MATLAB simulation program. We adopt single frame image obtained in underwater range gating laser imaging to identify, and through identifying and locating the different positions of target, we can improve

  18. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging, FSW monitoring with acoustic emission

    International Nuclear Information System (INIS)

    Stepinski, Tadeusz; Olofsson, Tomas; Wennerstroem, Erik

    2006-12-01

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2005/2006. In the first part of the report we propose a concept of monitoring of the friction stir welding (FSW) process by means of acoustic emission (AE) technique. First, we introduce the AE technique and then we present the principle of the system for monitoring the FSW process in cylindrical symmetry specific for the SKB canisters. We propose an omnidirectional circular array of ultrasonic transducers for receiving the AE signals generated by the FSW tool and the releases of the residual stress at canister's circumference. Finally, we review the theory of uniform circular arrays. The second part of the report is concerned with synthetic aperture focusing technique (SAFT) characterized by enhanced spatial resolution. We evaluate three different approaches to perform imaging with less computational cost than that of the extended SAFT (ESAFT) method proposed in our previous reports. First, a sparse version of ESAFT is presented, which solves the reconstruction problem only for a small set of the most probable scatterers in the image. A frequency domain the ω-k SAFT algorithm, which relies on the far-field approximation is presented in the second part. Finally, a detailed analysis of the most computationally intense step in the ESAFT and the sparse 2D deconvolution is presented. In the final part of the report we introduce basics of the 3D ultrasonic imaging that has a great potential in the inspection of the FSW welds. We discuss in some detail the three interrelated steps involved in the 3D ultrasonic imaging: data acquisition, 3D reconstruction, and 3D visualization

  19. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging, FSW monitoring with acoustic emission

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Olofsson, Tomas; Wennerstroem, Erik [Uppsala Univ., Dept. of Technical Sciences (Sweden). Signals and Systems

    2006-12-15

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2005/2006. In the first part of the report we propose a concept of monitoring of the friction stir welding (FSW) process by means of acoustic emission (AE) technique. First, we introduce the AE technique and then we present the principle of the system for monitoring the FSW process in cylindrical symmetry specific for the SKB canisters. We propose an omnidirectional circular array of ultrasonic transducers for receiving the AE signals generated by the FSW tool and the releases of the residual stress at canister's circumference. Finally, we review the theory of uniform circular arrays. The second part of the report is concerned with synthetic aperture focusing technique (SAFT) characterized by enhanced spatial resolution. We evaluate three different approaches to perform imaging with less computational cost than that of the extended SAFT (ESAFT) method proposed in our previous reports. First, a sparse version of ESAFT is presented, which solves the reconstruction problem only for a small set of the most probable scatterers in the image. A frequency domain the {omega}-k SAFT algorithm, which relies on the far-field approximation is presented in the second part. Finally, a detailed analysis of the most computationally intense step in the ESAFT and the sparse 2D deconvolution is presented. In the final part of the report we introduce basics of the 3D ultrasonic imaging that has a great potential in the inspection of the FSW welds. We discuss in some detail the three interrelated steps involved in the 3D ultrasonic imaging: data acquisition, 3D reconstruction, and 3D visualization.

  20. Experimental investigation on the fracture behaviour of black shale by acoustic emission monitoring and CT image analysis during uniaxial compression

    Science.gov (United States)

    Wang, Y.; Li, C. H.; Hu, Y. Z.

    2018-04-01

    Plenty of mechanical experiments have been done to investigate the deformation and failure characteristics of shale; however, the anisotropic failure mechanism has not been well studied. Here, laboratory Uniaxial Compressive Strength tests on cylindrical shale samples obtained by drilling at different inclinations to bedding plane were performed. The failure behaviours of the shale samples were studied by real-time acoustic emission (AE) monitoring and post-test X-ray computer tomography (CT) analysis. The experimental results suggest that the pronounced bedding planes of shale have a great influence on the mechanical properties and AE patterns. The AE counts and AE cumulative energy release curves clearly demonstrate different morphology, and the `U'-shaped curve relationship between the AE counts, AE cumulative energy release and bedding inclination was first documented. The post-test CT image analysis shows the crack patterns via 2-D image reconstructions, an index of stimulated fracture density is defined to represent the anisotropic failure mode of shale. What is more, the most striking finding is that the AE monitoring results are in good agreement with the CT analysis. The structural difference in the shale sample is the controlling factor resulting in the anisotropy of AE patterns. The pronounced bedding structure in the shale formation results in an anisotropy of elasticity, strength and AE information from which the changes in strength dominate the entire failure pattern of the shale samples.

  1. Using wavelet denoising and mathematical morphology in the segmentation technique applied to blood cells images.

    Science.gov (United States)

    Boix, Macarena; Cantó, Begoña

    2013-04-01

    Accurate image segmentation is used in medical diagnosis since this technique is a noninvasive pre-processing step for biomedical treatment. In this work we present an efficient segmentation method for medical image analysis. In particular, with this method blood cells can be segmented. For that, we combine the wavelet transform with morphological operations. Moreover, the wavelet thresholding technique is used to eliminate the noise and prepare the image for suitable segmentation. In wavelet denoising we determine the best wavelet that shows a segmentation with the largest area in the cell. We study different wavelet families and we conclude that the wavelet db1 is the best and it can serve for posterior works on blood pathologies. The proposed method generates goods results when it is applied on several images. Finally, the proposed algorithm made in MatLab environment is verified for a selected blood cells.

  2. Active filtering applied to radiographic images unfolded by the Richardson-Lucy algorithm

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Silvani, Maria Ines; Lopes, Ricardo T.

    2011-01-01

    Degradation of images caused by systematic uncertainties can be reduced when one knows the features of the spoiling agent. Typical uncertainties of this kind arise in radiographic images due to the non - zero resolution of the detector used to acquire them, and from the non-punctual character of the source employed in the acquisition, or from the beam divergence when extended sources are used. Both features blur the image, which, instead of a single point exhibits a spot with a vanishing edge, reproducing hence the point spread function - PSF of the system. Once this spoiling function is known, an inverse problem approach, involving inversion of matrices, can then be used to retrieve the original image. As these matrices are generally ill-conditioned, due to statistical fluctuation and truncation errors, iterative procedures should be applied, such as the Richardson-Lucy algorithm. This algorithm has been applied in this work to unfold radiographic images acquired by transmission of thermal neutrons and gamma-rays. After this procedure, the resulting images undergo an active filtering which fairly improves their final quality at a negligible cost in terms of processing time. The filter ruling the process is based on the matrix of the correction factors for the last iteration of the deconvolution procedure. Synthetic images degraded with a known PSF, and undergone to the same treatment, have been used as benchmark to evaluate the soundness of the developed active filtering procedure. The deconvolution and filtering algorithms have been incorporated to a Fortran program, written to deal with real images, generate the synthetic ones and display both. (author)

  3. Applying Deep Learning in Medical Images: The Case of Bone Age Estimation.

    Science.gov (United States)

    Lee, Jang Hyung; Kim, Kwang Gi

    2018-01-01

    A diagnostic need often arises to estimate bone age from X-ray images of the hand of a subject during the growth period. Together with measured physical height, such information may be used as indicators for the height growth prognosis of the subject. We present a way to apply the deep learning technique to medical image analysis using hand bone age estimation as an example. Age estimation was formulated as a regression problem with hand X-ray images as input and estimated age as output. A set of hand X-ray images was used to form a training set with which a regression model was trained. An image preprocessing procedure is described which reduces image variations across data instances that are unrelated to age-wise variation. The use of Caffe, a deep learning tool is demonstrated. A rather simple deep learning network was adopted and trained for tutorial purpose. A test set distinct from the training set was formed to assess the validity of the approach. The measured mean absolute difference value was 18.9 months, and the concordance correlation coefficient was 0.78. It is shown that the proposed deep learning-based neural network can be used to estimate a subject's age from hand X-ray images, which eliminates the need for tedious atlas look-ups in clinical environments and should improve the time and cost efficiency of the estimation process.

  4. IMAGE information monitoring and applied graphics software environment. Volume 4. Applications description

    International Nuclear Information System (INIS)

    Hallam, J.W.; Ng, K.B.; Upham, G.L.

    1986-09-01

    The EPRI Information Monitoring and Applied Graphics Environment (IMAGE) system is designed for 'fast proto-typing' of advanced concepts for computer-aided plant operations tools. It is a flexible software system which can be used for rapidly creating, dynamically driving and evaluating advanced operator aid displays. The software is written to be both host computer and graphic device independent. This four volume report includes an Executive Overview of the IMAGE package (Volume 1), followed by Software Description (Volume II), User's Guide (Volume III), and Description of Example Applications (Volume IV)

  5. Wavelet theory applied to remove noise and movement artifacts from images

    International Nuclear Information System (INIS)

    Blanco, S.; Cabrejas, M.L.; Carpintiero, S.; Costa, A.; Stenborg, J.

    2002-01-01

    The quality of the images is in direct relationship with the accuracy of the diagnosis. There are several physical and technical problems (signal to noise ratio, image distortions, geometrical defects, pattern recognition and movement corrections) associated with acquisition and processing devices, each of which require specific solutions. New generation equipment or appropriate quality control techniques, often solve the problem. The option, is trying to correct for image distortions existing on the reconstructed images using post processing mathematical filtering. In this paper a new developed software is described to correct the images and solve the above mentioned problems. Mathematical tools: To improve the signal to noise ratio, a noise reduction method, based on Multi Resolution Analysis with Wavelets, was used. The use of cubic spline wavelets as mother wavelets, is more convenient because they conform an orthogonal basis. For each multi resolution level, a 'hard thresholding' was applied. This means that the coefficients, which are strongly dependent on the images, are put to zero when they are smaller than a reference value. It is also possible to separate the movement of the structures under study from instrumental constraints or noise. To accomplish this, cross-correlations of particular sub-regions, in consecutive images, were performed. Since a quantitative estimation of the error introduced by both effects is rather difficult, a new technique was developed, a so-called trial and error technique (TET), via the identification of a particular subregion on consecutive images, provided there are sharp fixed features present in the considered subregion. This position, being the one in which the standard deviation is the smallest, is then chosen on the second image. Taking into account the time between images and the dynamic characteristic time, the Gaussian distribution confirms the absence of substantial variability form one image to the other. Results

  6. Synthetic Aperture Focusing Applied to Imaging Using a Rotating Single Element Transducer

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2007-01-01

    This paper applies the concept of virtual sources and mono-static synthetic aperture focusing (SAF) to 2-dimensional imaging with a single rotating mechanically focused concave element with the objective of improving lateral resolution and signal-to-noise ratio (SNR). The geometrical focal point...... function of a single emission. The effect of SAF with focal depth at 20 mm is negligible, caused by the small number of LRL applied. The great profit of the SAF is the increase in SNR. For the setup with focal depth at 20 rum the SAF SNR gain is 11 dB. The SNR gain of a setup with a VS at radius 10 mm...

  7. An explorative chemometric approach applied to hyperspectral images for the study of illuminated manuscripts

    Science.gov (United States)

    Catelli, Emilio; Randeberg, Lise Lyngsnes; Alsberg, Bjørn Kåre; Gebremariam, Kidane Fanta; Bracci, Silvano

    2017-04-01

    Hyperspectral imaging (HSI) is a fast non-invasive imaging technology recently applied in the field of art conservation. With the help of chemometrics, important information about the spectral properties and spatial distribution of pigments can be extracted from HSI data. With the intent of expanding the applications of chemometrics to the interpretation of hyperspectral images of historical documents, and, at the same time, to study the colorants and their spatial distribution on ancient illuminated manuscripts, an explorative chemometric approach is here presented. The method makes use of chemometric tools for spectral de-noising (minimum noise fraction (MNF)) and image analysis (multivariate image analysis (MIA) and iterative key set factor analysis (IKSFA)/spectral angle mapper (SAM)) which have given an efficient separation, classification and mapping of colorants from visible-near-infrared (VNIR) hyperspectral images of an ancient illuminated fragment. The identification of colorants was achieved by extracting and interpreting the VNIR spectra as well as by using a portable X-ray fluorescence (XRF) spectrometer.

  8. Applying Enhancement Filters in the Pre-processing of Images of Lymphoma

    International Nuclear Information System (INIS)

    Silva, Sérgio Henrique; Do Nascimento, Marcelo Zanchetta; Neves, Leandro Alves; Batista, Valério Ramos

    2015-01-01

    Lymphoma is a type of cancer that affects the immune system, and is classified as Hodgkin or non-Hodgkin. It is one of the ten types of cancer that are the most common on earth. Among all malignant neoplasms diagnosed in the world, lymphoma ranges from three to four percent of them. Our work presents a study of some filters devoted to enhancing images of lymphoma at the pre-processing step. Here the enhancement is useful for removing noise from the digital images. We have analysed the noise caused by different sources like room vibration, scraps and defocusing, and in the following classes of lymphoma: follicular, mantle cell and B-cell chronic lymphocytic leukemia. The filters Gaussian, Median and Mean-Shift were applied to different colour models (RGB, Lab and HSV). Afterwards, we performed a quantitative analysis of the images by means of the Structural Similarity Index. This was done in order to evaluate the similarity between the images. In all cases we have obtained a certainty of at least 75%, which rises to 99% if one considers only HSV. Namely, we have concluded that HSV is an important choice of colour model at pre-processing histological images of lymphoma, because in this case the resulting image will get the best enhancement

  9. Development of Acoustic Model-Based Iterative Reconstruction Technique for Thick-Concrete Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Almansouri, Hani [Purdue University; Clayton, Dwight A [ORNL; Kisner, Roger A [ORNL; Polsky, Yarom [ORNL; Bouman, Charlie [Purdue University; Santos-Villalobos, Hector J [ORNL

    2015-01-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well s health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.

  10. Development of Acoustic Model-Based Iterative Reconstruction Technique for Thick-Concrete Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Almansouri, Hani [Purdue University; Clayton, Dwight A [ORNL; Kisner, Roger A [ORNL; Polsky, Yarom [ORNL; Bouman, Charlie [Purdue University; Santos-Villalobos, Hector J [ORNL

    2016-01-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well's health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.

  11. Development of acoustic model-based iterative reconstruction technique for thick-concrete imaging

    Science.gov (United States)

    Almansouri, Hani; Clayton, Dwight; Kisner, Roger; Polsky, Yarom; Bouman, Charles; Santos-Villalobos, Hector

    2016-02-01

    Ultrasound signals have been used extensively for non-destructive evaluation (NDE). However, typical reconstruction techniques, such as the synthetic aperture focusing technique (SAFT), are limited to quasi-homogenous thin media. New ultrasonic systems and reconstruction algorithms are in need for one-sided NDE of non-homogenous thick objects. An application example space is imaging of reinforced concrete structures for commercial nuclear power plants (NPPs). These structures provide important foundation, support, shielding, and containment functions. Identification and management of aging and degradation of concrete structures is fundamental to the proposed long-term operation of NPPs. Another example is geothermal and oil/gas production wells. These multi-layered structures are composed of steel, cement, and several types of soil and rocks. Ultrasound systems with greater penetration range and image quality will allow for better monitoring of the well's health and prediction of high-pressure hydraulic fracturing of the rock. These application challenges need to be addressed with an integrated imaging approach, where the application, hardware, and reconstruction software are highly integrated and optimized. Therefore, we are developing an ultrasonic system with Model-Based Iterative Reconstruction (MBIR) as the image reconstruction backbone. As the first implementation of MBIR for ultrasonic signals, this paper document the first implementation of the algorithm and show reconstruction results for synthetically generated data.1

  12. Improving the resolution of three-dimensional acoustic imaging with planar phased arrays

    DEFF Research Database (Denmark)

    Xenaki, Angeliki; Jacobsen, Finn; Fernandez Grande, Efren

    2012-01-01

    a transformation of coordinates that tends to make the response to a point source, the point spread function, more shift invariant. The result is a significant improvement in sound source imaging in the transformed coordinate system. However, the inverse transformation to Cartesian coordinates introduces range...

  13. Applying GA for Optimizing the User Query in Image and Video Retrieval

    OpenAIRE

    Ehsan Lotfi

    2014-01-01

    In an information retrieval system, the query can be made by user sketch. The new method presented here, optimizes the user sketch and applies the optimized query to retrieval the information. This optimization may be used in Content-Based Image Retrieval (CBIR) and Content-Based Video Retrieval (CBVR) which is based on trajectory extraction. To optimize the retrieval process, one stage of retrieval is performed by the user sketch. The retrieval criterion is based on the proposed distance met...

  14. "Seeing is believing": perspectives of applying imaging technology in discovery toxicology.

    Science.gov (United States)

    Xu, Jinghai James; Dunn, Margaret Condon; Smith, Arthur Russell

    2009-11-01

    Efficiency and accuracy in addressing drug safety issues proactively are critical in minimizing late-stage drug attritions. Discovery toxicology has become a specialty subdivision of toxicology seeking to effectively provide early predictions and safety assessment in the drug discovery process. Among the many technologies utilized to select safer compounds for further development, in vitro imaging technology is one of the best characterized and validated to provide translatable biomarkers towards clinically-relevant outcomes of drug safety. By carefully applying imaging technologies in genetic, hepatic, and cardiac toxicology, and integrating them with the rest of the drug discovery processes, it was possible to demonstrate significant impact of imaging technology on drug research and development and substantial returns on investment.

  15. Digital image analysis applied to industrial nondestructive evaluation and automated parts assembly

    International Nuclear Information System (INIS)

    Janney, D.H.; Kruger, R.P.

    1979-01-01

    Many ideas of image enhancement and analysis are relevant to the needs of the nondestructive testing engineer. These ideas not only aid the engineer in the performance of his current responsibilities, they also open to him new areas of industrial development and automation which are logical extensions of classical testing problems. The paper begins with a tutorial on the fundamentals of computerized image enhancement as applied to nondestructive testing, then progresses through pattern recognition and automated inspection to automated, or robotic, assembly procedures. It is believed that such procedures are cost-effective in many instances, and are but the logical extension of those techniques now commonly used, but often limited to analysis of data from quality-assurance images. Many references are given in order to help the reader who wishes to pursue a given idea further

  16. The creation of inter-ethnic images for studies in applied psychology.

    Science.gov (United States)

    Vanezis, Maria; Vanezis, Peter; Minnis, Helen; McMillan, Alison; Gillies, Marjorie; Smith, Shubulade

    2003-10-01

    The facial transformation programme, is an integral part of the computerised three-dimensional facial reconstruction system, employed at the University of Glasgow for forensic and historical cases. It was applied to the creation of inter-ethnic images for use in studies to assess the response of various groups to facial appearance in the assessment of racial stereotyping. We initially acquired a three-dimensional facial image from a young black (Negroid) male volunteer, using our optical laser scanning system. This image was then used as a template over a Caucasian skull to produce a reconstruction using facial criteria applicable to white (Caucasian) males. The other image used was that of the facial template of the black male. A commercially available electronic identikit system, E-FIT was then used to add appropriate hair styles and open eyes to both images. In addition, on the 'Caucasian reconstruction' we were able to reduce the contrast and lighting on the face. This was relatively straightforward as we were using greyscale images rather than colour. The shape of the nose and lips on the white male were also altered to be more in keeping with Caucasoid average measurements. The resulting images were shown to a group of second-year clinical psychology students and their responses are discussed. Similar images may also be used in studies of racial stereotyping in different categories of professionals such as police, prison personnel, probation officers, social workers, potential employers, doctors, and others, in order to assess the response to individuals by facial appearance.

  17. Pattern recognition applied to infrared images for early alerts in fog

    Science.gov (United States)

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

    2014-09-01

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

  18. Versatile quantitative phase imaging system applied to high-speed, low noise and multimodal imaging (Conference Presentation)

    Science.gov (United States)

    Federici, Antoine; Aknoun, Sherazade; Savatier, Julien; Wattellier, Benoit F.

    2017-02-01

    Quadriwave lateral shearing interferometry (QWLSI) is a well-established quantitative phase imaging (QPI) technique based on the analysis of interference patterns of four diffraction orders by an optical grating set in front of an array detector [1]. As a QPI modality, this is a non-invasive imaging technique which allow to measure the optical path difference (OPD) of semi-transparent samples. We present a system enabling QWLSI with high-performance sCMOS cameras [2] and apply it to perform high-speed imaging, low noise as well as multimodal imaging. This modified QWLSI system contains a versatile optomechanical device which images the optical grating near the detector plane. Such a device is coupled with any kind of camera by varying its magnification. In this paper, we study the use of a sCMOS Zyla5.5 camera from Andor along with our modified QWLSI system. We will present high-speed live cell imaging, up to 200Hz frame rate, in order to follow intracellular fast motions while measuring the quantitative phase information. The structural and density information extracted from the OPD signal is complementary to the specific and localized fluorescence signal [2]. In addition, QPI detects cells even when the fluorophore is not expressed. This is very useful to follow a protein expression with time. The 10 µm spatial pixel resolution of our modified QWLSI associated to the high sensitivity of the Zyla5.5 enabling to perform high quality fluorescence imaging, we have carried out multimodal imaging revealing fine structures cells, like actin filaments, merged with the morphological information of the phase. References [1]. P. Bon, G. Maucort, B. Wattellier, and S. Monneret, "Quadriwave lateral shearing interferometry for quantitative phase microscopy of living cells," Opt. Express, vol. 17, pp. 13080-13094, 2009. [2] P. Bon, S. Lécart, E. Fort and S. Lévêque-Fort, "Fast label-free cytoskeletal network imaging in living mammalian cells," Biophysical journal, 106

  19. Virtual touch tissue quantification of acoustic radiation force impulse: a new ultrasound elastic imaging in the diagnosis of thyroid nodules.

    Directory of Open Access Journals (Sweden)

    Yi-Feng Zhang

    Full Text Available OBJECTIVE: Virtual touch tissue quantification (VTQ of acoustic radiation force impulse (ARFI is a new quantitative technique to measure tissue stiffness. The study was aimed to assess the usefulness of VTQ in the diagnosis of thyroid nodules. METHODS: 173 pathologically proven thyroid nodules in 142 patients were included and all were examined by conventional ultrasound (US, conventional elasticity imaging (EI and VTQ of ARFI. The tissue stiffness for VTQ was expressed as shear wave velocity (SWV (m/s. Receiver-operating characteristic curve (ROC analyses were performed to assess the diagnostic performance. Intra- and inter-observer reproducibility of VTQ measurement was assessed. RESULTS: The SWVs of benign and malignant thyroid nodules were 2.34±1.17 m/s (range: 0.61-9.00 m/s and 4.82±2.53 m/s (range: 2.32-9.00 m/s respectively (P20 mm and lowest for those ≤10 mm. The correlation coefficients were 0.904 for intraobserver measurement and 0.864 for interobserver measurement. CONCLUSIONS: VTQ of ARFI provides quantitative and reproducible information about the tissue stiffness, which is useful for the differentiation between benign and malignant thyroid nodules. The diagnostic performance of VTQ is higher than that of conventional EI.

  20. Garnet film rotator applied in polarizing microscope for domain image modulation (abstract)

    Science.gov (United States)

    Wakabayashi, K.; Numata, T.; Inokuchi, S.

    1991-04-01

    A garnet film polarization rotator placed before the analyzer in a polarizing microscope was investigated to obtain the difference image of a positive and a negative one of magnetic domain in real time along with an image processor. In the difference image, a nonmagnetic image can be reduced and hence the weak magnetic contrast enhanced. Theoretical calculation of S/N and contrast C of the domain image as a function of the rotation shows they take maxima at the rotation angle of 2.6° and 0.1°, respectively, with the extinction ratio of e=4×10-6 of a polarizing microscope. Thus, since the thickness of the garnet film required is 1 μm or so, the absorption by the garnet rotator does not bring a serious problem even in a visible region for the domain observation. The optimum rotation of the rotator for a high quality observation was obtained by a quantitative study of images obtained experimentally as well as by a visual evaluation. A magnetically unsaturated garnet film with perpendicular magnetization (i.e., multidomain) was employed as a rotator, in which the polarization rotation angle θm of the undeflected beam with respect to the light diffraction could be continuously varied by an applied magnetic field. The dependences of S/N and C on θm were measured, resulting in a well agreement between the measured and the calculated. The visually best image was obtained at θm=0.5° which made the product of S/N and C maximum. The domain image of the Kerr rotation angle of θk=0.22° was observed in S/N=47 dB and C=0.4 when Ar+ laser (λ=515 nm) of tenths of a watt was employed as a light source. Since the domain image with 47 dB S/N does not need an image summation for a noise reduction, a garnet film rotator makes it possible to invert the contrast of a domain image in a real time for an improved domain observation.

  1. Unfolding and smoothing applied to the quality enhancement of neutron tomographic images

    International Nuclear Information System (INIS)

    Almeida, Gevaldo L. de; Silvani, Maria I.; Lopes, Ricardo T.

    2008-01-01

    Resolution and contrast are the major parameters defining the quality of a computer-aided tomographic image. These parameters depend upon several features of the image acquisition system, such as detector resolution, geometrical arrangement of the source-object-detector, beam divergence, source strength, detector efficiency and counting time. Roughly, the detector finite resolution is the main source of systematic errors affecting the separation power of the image acquisition system, while the electronic noise and statistical fluctuation are responsible for the data dispersion, which spoils the contrast. An algorithm has been developed in this work aiming at the improvement of the image quality through the minimization of both types of errors. The systematic ones are reduced by a mathematical unfolding of the position spectra - used as projections to reconstruct the 2D-images - using the Line Spread Function - LSF of the neutron tomographic system. The principle behind this technique is that every single channel contains information about all channels of the spectrum, but it is concealed due to the automatic integration carried out by the detector. Therefore, knowing the shape of this curve, it is possible to retrieve the original spectra. These spectra are unfortunately corrupted by the unavoidable statistical fluctuation, and by oscillations arising from the unfolding process, which strongly affects the quality of the final unfolded image. In order to reduce this impact, the spectra have been filtered by a Fourier transform technique or smoothed with a least square fitting procedure. The algorithm has been applied to spectra of some test-bodies generated by an earlier developed tomographic simulator, which reproduces the spectra furnished by a thermal neutron tomographic system employing a position sensitive detector. The obtained results have shown that the unfolded spectra produce final images capable to resolve features otherwise not achievable with the

  2. Photo-acoustic imaging of coronary arteries with polymer optical fibers

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Broadway, Christian; Lamela, Horacio

    2014-01-01

    , Universidad Carlos III de Madrid under the TRIPOD project. TRIPOD (http://www.tripod-itn.eu) is a Marie Curie Initial Training Network located in the field of optical fibre sensors - an area where Europe has developed internationally competitive research and commercial activity. The aim is to significantly...... extend the range of appli cation of optical fibre grating sensors by developing a mature version of the technology in polymer optical fibres and thereby increase European competitiveness....

  3. Nonlinear time reversal signal processing techniques applied to acousto-mechanical imaging of complex materials

    Czech Academy of Sciences Publication Activity Database

    Dos Santos, S.; Dvořáková, Zuzana; Caliez, M.; Převorovský, Zdeněk

    2015-01-01

    Roč. 138, č. 3 (2015) ISSN 0001-4966 Institutional support: RVO:61388998 Keywords : acousto-mechanical characterization of skin aging * nonlinear elastic wave spectroscopy (NEWS) * PM-space statistical approach Subject RIV: BI - Acoustics

  4. Semi-supervised learning of hyperspectral image segmentation applied to vine tomatoes and table grapes

    Directory of Open Access Journals (Sweden)

    Jeroen van Roy

    2018-03-01

    Full Text Available Nowadays, quality inspection of fruit and vegetables is typically accomplished through visual inspection. Automation of this inspection is desirable to make it more objective. For this, hyperspectral imaging has been identified as a promising technique. When the field of view includes multiple objects, hypercubes should be segmented to assign individual pixels to different objects. Unsupervised and supervised methods have been proposed. While the latter are labour intensive as they require masking of the training images, the former are too computationally intensive for in-line use and may provide different results for different hypercubes. Therefore, a semi-supervised method is proposed to train a computationally efficient segmentation algorithm with minimal human interaction. As a first step, an unsupervised classification model is used to cluster spectra in similar groups. In the second step, a pixel selection algorithm applied to the output of the unsupervised classification is used to build a supervised model which is fast enough for in-line use. To evaluate this approach, it is applied to hypercubes of vine tomatoes and table grapes. After first derivative spectral preprocessing to remove intensity variation due to curvature and gloss effects, the unsupervised models segmented 86.11% of the vine tomato images correctly. Considering overall accuracy, sensitivity, specificity and time needed to segment one hypercube, partial least squares discriminant analysis (PLS-DA was found to be the best choice for in-line use, when using one training image. By adding a second image, the segmentation results improved considerably, yielding an overall accuracy of 96.95% for segmentation of vine tomatoes and 98.52% for segmentation of table grapes, demonstrating the added value of the learning phase in the algorithm.

  5. Least Square NUFFT Methods Applied to 2D and 3D Radially Encoded MR Image Reconstruction

    Science.gov (United States)

    Song, Jiayu; Liu, Qing H.; Gewalt, Sally L.; Cofer, Gary; Johnson, G. Allan

    2009-01-01

    Radially encoded MR imaging (MRI) has gained increasing attention in applications such as hyperpolarized gas imaging, contrast-enhanced MR angiography, and dynamic imaging, due to its motion insensitivity and improved artifact properties. However, since the technique collects k-space samples nonuniformly, multidimensional (especially 3D) radially sampled MRI image reconstruction is challenging. The balance between reconstruction accuracy and speed becomes critical when a large data set is processed. Kaiser-Bessel gridding reconstruction has been widely used for non-Cartesian reconstruction. The objective of this work is to provide an alternative reconstruction option in high dimensions with on-the-fly kernels calculation. The work develops general multi-dimensional least square nonuniform fast Fourier transform (LS-NUFFT) algorithms and incorporates them into a k-space simulation and image reconstruction framework. The method is then applied to reconstruct the radially encoded k-space, although the method addresses general nonuniformity and is applicable to any non-Cartesian patterns. Performance assessments are made by comparing the LS-NUFFT based method with the conventional Kaiser-Bessel gridding method for 2D and 3D radially encoded computer simulated phantoms and physically scanned phantoms. The results show that the LS-NUFFT reconstruction method has better accuracy-speed efficiency than the Kaiser-Bessel gridding method when the kernel weights are calculated on the fly. The accuracy of the LS-NUFFT method depends on the choice of scaling factor, and it is found that for a particular conventional kernel function, using its corresponding deapodization function as scaling factor and utilizing it into the LS-NUFFT framework has the potential to improve accuracy. When a cosine scaling factor is used, in particular, the LS-NUFFT method is faster than Kaiser-Bessel gridding method because of a quasi closed-form solution. The method is successfully applied to 2D and

  6. Communication Acoustics

    DEFF Research Database (Denmark)

    Blauert, Jens

    Communication Acoustics deals with the fundamentals of those areas of acoustics which are related to modern communication technologies. Due to the advent of digital signal processing and recording in acoustics, these areas have enjoyed an enormous upswing during the last 4 decades. The book...... the book a source of valuable information for those who want to improve or refresh their knowledge in the field of communication acoustics - and to work their way deeper into it. Due to its interdisciplinary character Communication Acoustics is bound to attract readers from many different areas, such as......: acoustics, cognitive science, speech science, and communication technology....

  7. An information-theoretical approach to image resolution applied to neutron imaging detectors based upon individual discriminator signals

    International Nuclear Information System (INIS)

    Clergeau, Jean-Francois; Ferraton, Matthieu; Guerard, Bruno; Khaplanov, Anton; Piscitelli, Francesco; Platz, Martin; Rigal, Jean-Marie; Van Esch, Patrick; Daulle, Thibault

    2013-06-01

    1D or 2D neutron imaging detectors with individual wire or strip readout using discriminators have the advantage of being able to treat several neutron impacts partially overlapping in time, hence reducing global dead time. A single neutron impact usually gives rise to several discriminator signals. In this paper, we introduce an information-theoretical definition of image resolution. Two point-like spots of neutron impacts with a given distance between them act as a source of information (each neutron hit belongs to one spot or the other), and the detector plus signal treatment is regarded as an imperfect communication channel that transmits this information. The maximal mutual information obtained from this channel as a function of the distance between the spots allows to define a calibration-independent measure of resolution. We then apply this measure to quantify the power of resolution of different algorithms treating these individual discriminator signals which can be implemented in firmware. The method is then applied to different detectors existing at the ILL. Center-of-gravity methods usually improve the resolution over best-wire algorithms which are the standard way of treating these signals. (authors)

  8. An information-theoretical approach to image resolution applied to neutron imaging detectors based upon individual discriminator signals

    Energy Technology Data Exchange (ETDEWEB)

    Clergeau, Jean-Francois; Ferraton, Matthieu; Guerard, Bruno; Khaplanov, Anton; Piscitelli, Francesco; Platz, Martin; Rigal, Jean-Marie; Van Esch, Patrick [Institut Laue Langevin, Neutron Detector Service, Grenoble (France); Daulle, Thibault [PHELMA Grenoble - INP Grenoble (France)

    2013-06-15

    1D or 2D neutron imaging detectors with individual wire or strip readout using discriminators have the advantage of being able to treat several neutron impacts partially overlapping in time, hence reducing global dead time. A single neutron impact usually gives rise to several discriminator signals. In this paper, we introduce an information-theoretical definition of image resolution. Two point-like spots of neutron impacts with a given distance between them act as a source of information (each neutron hit belongs to one spot or the other), and the detector plus signal treatment is regarded as an imperfect communication channel that transmits this information. The maximal mutual information obtained from this channel as a function of the distance between the spots allows to define a calibration-independent measure of resolution. We then apply this measure to quantify the power of resolution of different algorithms treating these individual discriminator signals which can be implemented in firmware. The method is then applied to different detectors existing at the ILL. Center-of-gravity methods usually improve the resolution over best-wire algorithms which are the standard way of treating these signals. (authors)

  9. The monocular visual imaging technology model applied in the airport surface surveillance

    Science.gov (United States)

    Qin, Zhe; Wang, Jian; Huang, Chao

    2013-08-01

    At present, the civil aviation airports use the surface surveillance radar monitoring and positioning systems to monitor the aircrafts, vehicles and the other moving objects. Surface surveillance radars can cover most of the airport scenes, but because of the terminals, covered bridges and other buildings geometry, surface surveillance radar systems inevitably have some small segment blind spots. This paper presents a monocular vision imaging technology model for airport surface surveillance, achieving the perception of scenes of moving objects such as aircrafts, vehicles and personnel location. This new model provides an important complement for airport surface surveillance, which is different from the traditional surface surveillance radar techniques. Such technique not only provides clear objects activities screen for the ATC, but also provides image recognition and positioning of moving targets in this area. Thereby it can improve the work efficiency of the airport operations and avoid the conflict between the aircrafts and vehicles. This paper first introduces the monocular visual imaging technology model applied in the airport surface surveillance and then the monocular vision measurement accuracy analysis of the model. The monocular visual imaging technology model is simple, low cost, and highly efficient. It is an advanced monitoring technique which can make up blind spot area of the surface surveillance radar monitoring and positioning systems.

  10. Acoustic field modulation in regenerators

    Science.gov (United States)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  11. Controlling sound with acoustic metamaterials

    DEFF Research Database (Denmark)

    Cummer, Steven A. ; Christensen, Johan; Alù, Andrea

    2016-01-01

    Acoustic metamaterials can manipulate and control sound waves in ways that are not possible in conventional materials. Metamaterials with zero, or even negative, refractive index for sound offer new possibilities for acoustic imaging and for the control of sound at subwavelength scales....... The combination of transformation acoustics theory and highly anisotropic acoustic metamaterials enables precise control over the deformation of sound fields, which can be used, for example, to hide or cloak objects from incident acoustic energy. Active acoustic metamaterials use external control to create......-scale metamaterial structures and converting laboratory experiments into useful devices. In this Review, we outline the designs and properties of materials with unusual acoustic parameters (for example, negative refractive index), discuss examples of extreme manipulation of sound and, finally, provide an overview...

  12. Acoustic Neuroma

    Science.gov (United States)

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  13. Model simulations of line-of-sight effects in airglow imaging of acoustic and fast gravity waves from ground and space

    Science.gov (United States)

    Aguilar Guerrero, J.; Snively, J. B.

    2017-12-01

    Acoustic waves (AWs) have been predicted to be detectable by imaging systems for the OH airglow layer [Snively, GRL, 40, 2013], and have been identified in spectrometer data [Pilger et al., JASP, 104, 2013]. AWs are weak in the mesopause region, but can attain large amplitudes in the F region [Garcia et al., GRL, 40, 2013] and have local impacts on the thermosphere and ionosphere. Similarly, fast GWs, with phase speeds over 100 m/s, may propagate to the thermosphere and impart significant local body forcing [Vadas and Fritts, JASTP, 66, 2004]. Both have been clearly identified in ionospheric total electron content (TEC), such as following the 2013 Moore, OK, EF5 tornado [Nishioka et al., GRL, 40, 2013] and following the 2011 Tohoku-Oki tsunami [e.g., Galvan et al., RS, 47, 2012, and references therein], but AWs have yet to be unambiguously imaged in MLT data and fast GWs have low amplitudes near the threshold of detection; nevertheless, recent imaging systems have sufficient spatial and temporal resolution and sensitivity to detect both AWs and fast GWs with short periods [e.g., Pautet et al., AO, 53, 2014]. The associated detectability challenges are related to the transient nature of their signatures and to systematic challenges due to line-of-sight (LOS) effects such as enhancements and cancelations due to integration along aligned or oblique wavefronts and geometric intensity enhancements. We employ a simulated airglow imager framework that incorporates 2D and 3D emission rate data and performs the necessary LOS integrations for synthetic imaging from ground- and space-based platforms to assess relative intensity and temperature perturbations. We simulate acoustic and fast gravity wave perturbations to the hydroxyl layer from a nonlinear, compressible model [e.g., Snively, 2013] for different idealized and realistic test cases. The results show clear signal enhancements when acoustic waves are imaged off-zenith or off-nadir and the temporal evolution of these

  14. Acoustic resonances in microfluidic chips: full-image micro-PIV experiments and numerical simulations

    DEFF Research Database (Denmark)

    Hagsäter, Melker; Jensen, Thomas Glasdam; Bruus, Henrik

    2007-01-01

    control of the formation and arrangement of liquid/liquid phase boundaries. The two immiscible phases which are injected separately into the microchannel are taken from a polyethylene glycol (PEG)–dextran system. The side walls of the channel are partially made of gel material which serves as an ion......) is introduced into the PEG-rich phase, it can easily be transferred into the dextran-rich phase via an applied electric field of low strength or just by diffusion. In the reverse case, up to a certain field strength the transfer to the opposing phase is strongly inhibited. Only if the field strength is further...... increased will the BSA molecules leave the dextran-rich phase almost completely....

  15. Exploration on practice teaching reform of Photoelectric Image Processing course under applied transformation

    Science.gov (United States)

    Cao, Binfang; Li, Xiaoqin; Liu, Changqing; Li, Jianqi

    2017-08-01

    With the further applied transformation of local colleges, teachers are urgently needed to make corresponding changes in the teaching content and methods from different courses. The article discusses practice teaching reform of the Photoelectric Image Processing course in the Optoelectronic Information Science and Engineering major. The Digital Signal Processing (DSP) platform is introduced to the experimental teaching. It will mobilize and inspire students and also enhance their learning motivation and innovation through specific examples. The course via teaching practice process has become the most popular course among students, which will further drive students' enthusiasm and confidence to participate in all kinds of electronic competitions.

  16. Lean Six Sigma applied to a process innovation in a mexican health institute's imaging department.

    Science.gov (United States)

    Garcia-Porres, J; Ortiz-Posadas, M R; Pimentel-Aguilar, A B

    2008-01-01

    Delivery of services to a patient has to be given with an acceptable measure of quality that can be monitored through the patient's satisfaction. The objective of this work was to innovate processes eliminating waste and non value-added work in processes done at the Imaging Department in the National Institute of Respiratory Diseases (INER for its Spanish acronym) in Mexico City, to decrease the time a patient spends in a study and increase satisfaction. This innovation will be done using Lean Six Sigma tools and applied in a pilot program.

  17. Imaging of microwave-induced acoustic fields in LiNbO{sub 3} by high-performance Brillouin microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, B [Lab. Europeen de Recherche Univ.: Saarland-Lorraine, Univ. des Saarlandes, D-66041 Saarbruecken (Germany)]|[Lab. de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Univ. H. Poincare, Nancy I, F-54506 (France); Krueger, J K [Lab. Europeen de Recherche Univ.: Saarland-Lorraine, Univ. des Saarlandes, D-66041 Saarbruecken (Germany)]|[Fachrichtung 7.2, Experimentalphysik, Univ. des Saarlandes, Bau 38, D-66041 Saarbruecken (Germany); Elmazria, O [Laboratoire Europeen de Recherche Universitaire: Saarland-Lorraine, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany)]|[Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Bouvot, L [Laboratoire Europeen de Recherche Universitaire: Saarland-Lorraine, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany)]|[Laboratoire de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Universite H. Poincare, Nancy I, F-54506 (France); Mainka, J [Laboratoire Europeen de Recherche Universitaire: Saarland-Lorraine, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany)]|[Fachrichtung 7.2, Experimentalphysik, Universitaet des Saarlandes, Bau 38, D-66041 Saarbruecken (Germany); Sanctuary, R [Laboratoire Europeen de Recherche Universitaire: Saarland-Lorraine, Universitaet des Saarlandes, D-66041 Saarbruecken (Germany)]|[Laboratoire de Physique des Materiaux, Campus Luxembourg-Limpertsberg, L-1511 Luxembourg (Luxembourg); Rouxel, D [Lab. Europeen de Recherche Univ.: Saarland-Lorraine, Univ. des Saarlandes, D-66041 Saarbruecken (Germany)]|[Lab. de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Univ. H. Poincare, Nancy I, F-54506 (France); Alnot, P [Lab. Europeen de Recherche Univ.: Saarland-Lorraine, Univ. des Saarlandes, D-66041 Saarbruecken (Germany)]|[Lab. de Physique des Milieux Ionises et Applications, CNRS-UMR 7040, Univ. H. Poincare, Nancy I, F-54506 (France)

    2005-06-21

    High performance Brillouin microscopy (BM) has been used to characterize the spatial distribution of piezoelectrically induced acoustic fields excited at microwave frequencies in a LiNbO{sub 3} single crystal. It is demonstrated that under suitable conditions BM is able to detect microwave-induced bulk as well as surface acoustic waves. Brillouin spectroscopy is able to probe sound wave intensities of induced phonons, which are as small as those of thermal phonons.

  18. Optimization of SPECT calibration for quantification of images applied to dosimetry with iodine-131

    International Nuclear Information System (INIS)

    Carvalho, Samira Marques de

    2018-01-01

    SPECT systems calibration plays an essential role in the accuracy of the quantification of images. In this work, in its first stage, an optimized SPECT calibration method was proposed for 131 I studies, considering the partial volume effect (PVE) and the position of the calibration source. In the second stage, the study aimed to investigate the impact of count density and reconstruction parameters on the determination of the calibration factor and the quantification of the image in dosimetry studies, considering the reality of clinical practice in Brazil. In the final step, the study aimed evaluating the influence of several factors in the calibration for absorbed dose calculation using Monte Carlo simulations (MC) GATE code. Calibration was performed by determining a calibration curve (sensitivity versus volume) obtained by applying different thresholds. Then, the calibration factors were determined with an exponential function adjustment. Images were performed with high and low counts densities for several source positions within the simulator. To validate the calibration method, the calibration factors were used for absolute quantification of the total reference activities. The images were reconstructed adopting two approaches of different parameters, usually used in patient images. The methodology developed for the calibration of the tomographic system was easier and faster to implement than other procedures suggested to improve the accuracy of the results. The study also revealed the influence of the location of the calibration source, demonstrating better precision in the absolute quantification considering the location of the target region during the calibration of the system. The study applied in the Brazilian thyroid protocol suggests the revision of the calibration of the SPECT system, including different positions for the reference source, besides acquisitions considering the Signal to Noise Ratio (SNR) of the images. Finally, the doses obtained with the

  19. Age-related changes in liver, kidney, and spleen stiffness in healthy children measured with acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mi-Jung, E-mail: mjl1213@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Yonsei University, College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Myung-Joon, E-mail: mjkim@yuhs.ac [Department of Radiology and Research Institute of Radiological Science, Severance Children' s Hospital, Yonsei University, College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Han, Kyung Hwa, E-mail: khhan@yuhs.ac [Biostatistics Collaboration Unit, Yonsei University, College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Yoon, Choon Sik, E-mail: yooncs58@yuhs.ac [Department of Radiology, Gangnam Severance Hospital, Yonsei University, College of Medicine, 211 Unjoo-ro, Gangnam-gu, Seoul (Korea, Republic of)

    2013-06-15

    Objectives: To evaluate the feasibility and age-related changes of shear wave velocity (SWV) in normal livers, kidneys, and spleens of children using acoustic radiation force impulse (ARFI) imaging. Materials and methods: Healthy pediatric volunteers prospectively underwent abdominal ultrasonography and ARFI. The subjects were divided into three groups according to age: group 1: <5 years old; group 2: 5–10 years old; and group 3: >10 years old. The SWV was measured using a 4–9 MHz linear probe for group 1 and a 1–4 MHz convex probe for groups 2 and 3. Three valid SWV measurements were acquired for each organ. Results: Two hundred and two children (92 male, 110 female) with an average age of 8.1 years (±4.7) were included in this study and had a successful measurement rate of 97% (196/202). The mean SWVs were 1.12 m/s for the liver, 2.19 m/s for the right kidney, 2.33 m/s for the left kidney, and 2.25 m/s for the spleen. The SWVs for the right and left kidneys, and the spleen showed age-related changes in all children (p < 0.001). And the SWVs for the kidneys increased with age in group 1, and those for the liver changed with age in group 3. Conclusions: ARFI measurements are feasible for solid abdominal organs in children using high or low frequency probes. The mean ARFI SWV for the kidneys increased according to age in children less than 5 years of age and in the liver, it changed with age in children over 10.

  20. Acoustic radiation force impulse imaging with Virtual Touch™ tissue quantification: mean shear wave velocity of malignant and benign breast masses.

    Science.gov (United States)

    Wojcinski, Sebastian; Brandhorst, Kathrin; Sadigh, Gelareh; Hillemanns, Peter; Degenhardt, Friedrich

    2013-01-01

    Acoustic radiation force impulse imaging (ARFI) with Virtual Touch™ tissue quantification (VTTQ) enables the determination of shear wave velocity (SWV) in meters per second (m/s). The aim of our study was to describe the mean SWV in normal breast tissue and various breast masses. We performed measurements of SWV with ARFI VTTQ in 145 breast masses (57 malignant, 88 benign) and in the adjacent breast parenchyma and adipose tissue. The mean SWV as well as the rate of successful measurements were analyzed. The difference between adipose tissue and parenchyma was statistically significant (3.05 versus 3.65 m/s) (P breast masses, numerous measurements exceeded the upper limit of possible measurement (≥9.10 m/s, indicated as "X.XX m/s"). Nevertheless, the difference between the malignant and benign masses was statistically significant (8.38 ± 1.99 m/s versus 5.39 ± 2.95 m/s) (P < 0.001). The best diagnostic accuracy (75.9%) was achieved when the cutoff point for malignancy was set to 9.10 m/s in ARFI VTTQ. This implies that the SWV was regarded as suspicious when the upper limit of possible measurement was exceeded and the machine returned the value X.XX m/s. In conclusion, ARFI VTTQ is a feasible method for measurement of SWV in a region of interest. Furthermore, we propose the event of a highly elevated SWV as a significant criterion for malignancy. However, the method is technically not yet fully developed, and the problem of unsuccessful measurements must still be solved.

  1. Applying a CAD-generated imaging marker to assess short-term breast cancer risk

    Science.gov (United States)

    Mirniaharikandehei, Seyedehnafiseh; Zarafshani, Ali; Heidari, Morteza; Wang, Yunzhi; Aghaei, Faranak; Zheng, Bin

    2018-02-01

    Although whether using computer-aided detection (CAD) helps improve radiologists' performance in reading and interpreting mammograms is controversy due to higher false-positive detection rates, objective of this study is to investigate and test a new hypothesis that CAD-generated false-positives, in particular, the bilateral summation of false-positives, is a potential imaging marker associated with short-term breast cancer risk. An image dataset involving negative screening mammograms acquired from 1,044 women was retrospectively assembled. Each case involves 4 images of craniocaudal (CC) and mediolateral oblique (MLO) view of the left and right breasts. In the next subsequent mammography screening, 402 cases were positive for cancer detected and 642 remained negative. A CAD scheme was applied to process all "prior" negative mammograms. Some features from CAD scheme were extracted, which include detection seeds, the total number of false-positive regions, an average of detection scores and the sum of detection scores in CC and MLO view images. Then the features computed from two bilateral images of left and right breasts from either CC or MLO view were combined. In order to predict the likelihood of each testing case being positive in the next subsequent screening, two logistic regression models were trained and tested using a leave-one-case-out based cross-validation method. Data analysis demonstrated the maximum prediction accuracy with an area under a ROC curve of AUC=0.65+/-0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of [2.95, 6.83]. The results also illustrated an increasing trend in the adjusted odds ratio and risk prediction scores (pbreast cancer risk.

  2. Acoustic levitator for containerless measurements on low temperature liquids

    Energy Technology Data Exchange (ETDEWEB)

    Benmore, Chris J [Argonne National Laboratory (ANL); Weber, Richard [Argonne National Laboratory (ANL); Neuefeind, Joerg C [ORNL; Rey, Charles A A [Charles Ray, Inc.

    2009-01-01

    A single-axis acoustic levitator was constructed and used to levitate liquid and solid drops at temperatures from -40 to +40 C. The levitator consisted of: (i) two acoustic transducers mounted on a rigid vertical support that was bolted to an optical breadboard, (ii) a acoustic power supply that controlled acoustic intensity, relative phase of the drive to the transducers, and could modulate the acoustic forces at frequencies up to 1kHz, (iii) a video camera, and (iv) a system for providing a stream of controlled temperature gas flow over the sample. The acoustic transducers were operated at their resonant frequency of ~ 22 kHz and could produce sound pressure levels up to 160 dB. The force applied by the acoustic field could be modulated using a frequency generator to excite oscillations in the sample. Sample temperature was controlled using a modified Cryostream Plus and measured using thermocouples and an infrared thermal imager. The levitator was installed at x-ray beamline 11 ID-C at the Advanced Photon Source and used to investigate the structure of supercooled liquids.

  3. Acoustic radiation force impulse imaging with Virtual Touch™ tissue quantification: mean shear wave velocity of malignant and benign breast masses

    Directory of Open Access Journals (Sweden)

    Wojcinski S

    2013-09-01

    Full Text Available Sebastian Wojcinski,1 Kathrin Brandhorst,2 Gelareh Sadigh,3 Peter Hillemanns,1 Friedrich Degenhardt2 1Department of Obstetrics and Gynecology, Hannover Medical School, Hannover, Germany; 2Department of Obstetrics and Gynecology, Franziskus Hospital, Bielefeld, Germany; 3Department of Radiology, Emory University, Atlanta, GA, USA Abstract: Acoustic radiation force impulse imaging (ARFI with Virtual Touch™ tissue quantification (VTTQ enables the determination of shear wave velocity (SWV in meters per second (m/s. The aim of our study was to describe the mean SWV in normal breast tissue and various breast masses. We performed measurements of SWV with ARFI VTTQ in 145 breast masses (57 malignant, 88 benign and in the adjacent breast parenchyma and adipose tissue. The mean SWV as well as the rate of successful measurements were analyzed. The difference between adipose tissue and parenchyma was statistically significant (3.05 versus 3.65 m/s (P < 0.001. Focusing on breast masses, numerous measurements exceeded the upper limit of possible measurement (≥9.10 m/s, indicated as "X.XX m/s". Nevertheless, the difference between the malignant and benign masses was statistically significant (8.38 ± 1.99 m/s versus 5.39 ± 2.95 m/s (P < 0.001. The best diagnostic accuracy (75.9% was achieved when the cutoff point for malignancy was set to 9.10 m/s in ARFI VTTQ. This implies that the SWV was regarded as suspicious when the upper limit of possible measurement was exceeded and the machine returned the value X.XX m/s. In conclusion, ARFI VTTQ is a feasible method for measurement of SWV in a region of interest. Furthermore, we propose the event of a highly elevated SWV as a significant criterion for malignancy. However, the method is technically not yet fully developed, and the problem of unsuccessful measurements must still be solved. Keywords: ARFI VTTQ, elastography, ultrasound, breast imaging

  4. Multifocus microscopy with precise color multi-phase diffractive optics applied in functional neuronal imaging.

    Science.gov (United States)

    Abrahamsson, Sara; Ilic, Rob; Wisniewski, Jan; Mehl, Brian; Yu, Liya; Chen, Lei; Davanco, Marcelo; Oudjedi, Laura; Fiche, Jean-Bernard; Hajj, Bassam; Jin, Xin; Pulupa, Joan; Cho, Christine; Mir, Mustafa; El Beheiry, Mohamed; Darzacq, Xavier; Nollmann, Marcelo; Dahan, Maxime; Wu, Carl; Lionnet, Timothée; Liddle, J Alexander; Bargmann, Cornelia I

    2016-03-01

    Multifocus microscopy (MFM) allows high-resolution instantaneous three-dimensional (3D) imaging and has been applied to study biological specimens ranging from single molecules inside cells nuclei to entire embryos. We here describe pattern designs and nanofabrication methods for diffractive optics that optimize the light-efficiency of the central optical component of MFM: the diffractive multifocus grating (MFG). We also implement a "precise color" MFM layout with MFGs tailored to individual fluorophores in separate optical arms. The reported advancements enable faster and brighter volumetric time-lapse imaging of biological samples. In live microscopy applications, photon budget is a critical parameter and light-efficiency must be optimized to obtain the fastest possible frame rate while minimizing photodamage. We provide comprehensive descriptions and code for designing diffractive optical devices, and a detailed methods description for nanofabrication of devices. Theoretical efficiencies of reported designs is ≈90% and we have obtained efficiencies of > 80% in MFGs of our own manufacture. We demonstrate the performance of a multi-phase MFG in 3D functional neuronal imaging in living C. elegans.

  5. Acoustic cloaking and transformation acoustics

    International Nuclear Information System (INIS)

    Chen Huanyang; Chan, C T

    2010-01-01

    In this review, we give a brief introduction to the application of the new technique of transformation acoustics, which draws on a correspondence between coordinate transformation and material properties. The technique is formulated for both acoustic waves and linear liquid surface waves. Some interesting conceptual devices can be designed for manipulating acoustic waves. For example, we can design acoustic cloaks that make an object invisible to acoustic waves, and the cloak can either encompass or lie outside the object to be concealed. Transformation acoustics, as an analog of transformation optics, can go beyond invisibility cloaking. As an illustration for manipulating linear liquid surface waves, we show that a liquid wave rotator can be designed and fabricated to rotate the wave front. The acoustic transformation media require acoustic materials which are anisotropic and inhomogeneous. Such materials are difficult to find in nature. However, composite materials with embedded sub-wavelength resonators can in principle be made and such 'acoustic metamaterials' can exhibit nearly arbitrary values of effective density and modulus tensors to satisfy the demanding material requirements in transformation acoustics. We introduce resonant sonic materials and Helmholtz resonators as examples of acoustic metamaterials that exhibit resonant behaviour in effective density and effective modulus. (topical review)

  6. Comparison of acoustic radiation force impulse imaging (ARFI) to liver biopsy histologic scores in the evaluation of chronic liver disease: A pilot study.

    Science.gov (United States)

    Haque, Mazhar; Robinson, Charlotte; Owen, David; Yoshida, Eric M; Harris, Alison

    2010-01-01

    Acoustic Radiation Force Impulse Imaging (ARFI) is a novel non invasive technique studying the localized mechanical properties of tissue by utilising short, high intensity acoustic pulses (shear wave pulses) to assess the mechanical response (tissue displacement), providing a measure of tissue elasticity. The aim of this study is to investigate the feasibility of ARFI imaging as a non-invasive method for the assessment of liver fibrosis compared to liver biopsy scores. A prospective blind comparison study of ARFI elastography (Virtual Touch Imaging., ACUSON S2000 Ultrasound Unit, Siemens, Mountain View CA) in a consecutive series of patients who underwent liver biopsy for assessment of fibrosis in chronic liver disease. ARFI shear-wave propagation velocity was measured in meters per second. Mean ARFI velocities were compared with both Batts-Ludwig (F0 to F4) and Modified Ishak scores (F0 to F4) for fibrosis in liver biopsy findings. Twenty-one patients with chronic liver disease (Hepatitis C (HCV) =16, Hepatitis B (HBV) = 1, both HCV and HBV = 1 Alcoholic liver disease (ALD) = 1, others = 2) underwent ARFI and liver biopsy on the same day. The Spearman correlation coefficients between the median values of the ARFI measurements and the histological fibrosis stage of the Modified Ishak score and Batts-Lud- (3) wig score were both highly significant (p shak score in chronic liver disease. It.s accuracy in prediction of severe fibrosis and cirrhosis is maximal in comparison with earlier stages.

  7. Evaluation of multichannel Wiener filters applied to fine resolution passive microwave images of first-year sea ice

    Science.gov (United States)

    Full, William E.; Eppler, Duane T.

    1993-01-01

    The effectivity of multichannel Wiener filters to improve images obtained with passive microwave systems was investigated by applying Wiener filters to passive microwave images of first-year sea ice. Four major parameters which define the filter were varied: the lag or pixel offset between the original and the desired scenes, filter length, the number of lines in the filter, and the weight applied to the empirical correlation functions. The effect of each variable on the image quality was assessed by visually comparing the results. It was found that the application of multichannel Wiener theory to passive microwave images of first-year sea ice resulted in visually sharper images with enhanced textural features and less high-frequency noise. However, Wiener filters induced a slight blocky grain to the image and could produce a type of ringing along scan lines traversing sharp intensity contrasts.

  8. Added clinical value of applying myocardial deformation imaging to assess right ventricular function.

    Science.gov (United States)

    Sokalskis, Vladislavs; Peluso, Diletta; Jagodzinski, Annika; Sinning, Christoph

    2017-06-01

    Right heart dysfunction has been found to be a strong prognostic factor predicting adverse outcome in various cardiopulmonary diseases. Conventional echocardiographic measurements can be limited by geometrical assumptions and impaired reproducibility. Speckle tracking-derived strain provides a robust quantification of right ventricular function. It explicitly evaluates myocardial deformation, as opposed to tissue Doppler-derived strain, which is computed from tissue velocity gradients. Right ventricular longitudinal strain provides a sensitive tool for detecting right ventricular dysfunction, even at subclinical levels. Moreover, the longitudinal strain can be applied for prognostic stratification of patients with pulmonary hypertension, pulmonary embolism, and congestive heart failure. Speckle tracking-derived right atrial strain, right ventricular longitudinal strain-derived mechanical dyssynchrony, and three-dimensional echocardiography-derived strain are emerging imaging parameters and methods. Their application in research is paving the way for their clinical use. © 2017, Wiley Periodicals, Inc.

  9. Imaging and quantitative data acquisition of biological cell walls with Atomic Force Microscopy and Scanning Acoustic Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tittmann, B. R. [Penn State; Xi, X. [Penn State

    2014-09-01

    This chapter demonstrates the feasibility of Atomic Force Microscopy (AFM) and High Frequency Scanning Acoustic Microscopy (HF-SAM) as tools to characterize biological tissues. Both the AFM and the SAM have shown to provide imaging (with different resolution) and quantitative elasticity measuring abilities. Plant cell walls with minimal disturbance and under conditions of their native state have been examined with these two kinds of microscopy. After descriptions of both the SAM and AFM, their special features and the typical sample preparation is discussed. The sample preparation is focused here on epidermal peels of onion scales and celery epidermis cells which were sectioned for the AFM to visualize the inner surface (closest to the plasma membrane) of the outer epidermal wall. The nm-wide cellulose microfibrils orientation and multilayer structure were clearly observed. The microfibril orientation and alignment tend to be more organized in older scales compared with younger scales. The onion epidermis cell wall was also used as a test analog to study cell wall elasticity by the AFM nanoindentation and the SAM V(z) feature. The novelty in this work was to demonstrate the capability of these two techniques to analyze isolated, single layered plant cell walls in their natural state. AFM nanoindentation was also used to probe the effects of Ethylenediaminetetraacetic acid (EDTA), and calcium ion treatment to modify pectin networks in cell walls. The results suggest a significant modulus increase in the calcium ion treatment and a slight decrease in EDTA treatment. To complement the AFM measurements, the HF-SAM was used to obtain the V(z) signatures of the onion epidermis. These measurements were focused on documenting the effect of pectinase enzyme treatment. The results indicate a significant change in the V(z) signature curves with time into the enzyme treatment. Thus AFM and HF-SAM open the door to a systematic nondestructive structure and mechanical property

  10. Accuracy Investigation of Creating Orthophotomaps Based on Images Obtained by Applying Trimble-UX5 UAV

    Science.gov (United States)

    Hlotov, Volodymyr; Hunina, Alla; Siejka, Zbigniew

    2017-06-01

    The main purpose of this work is to confirm the possibility of making largescale orthophotomaps applying unmanned aerial vehicle (UAV) Trimble- UX5. A planned altitude reference of the studying territory was carried out before to the aerial surveying. The studying territory has been marked with distinctive checkpoints in the form of triangles (0.5 × 0.5 × 0.2 m). The checkpoints used to precise the accuracy of orthophotomap have been marked with similar triangles. To determine marked reference point coordinates and check-points method of GNSS in real-time kinematics (RTK) measuring has been applied. Projecting of aerial surveying has been done with the help of installed Trimble Access Aerial Imaging, having been used to run out the UX5. Aerial survey out of the Trimble UX5 UAV has been done with the help of the digital camera SONY NEX-5R from 200m and 300 m altitude. These aerial surveying data have been calculated applying special photogrammetric software Pix 4D. The orthophotomap of the surveying objects has been made with its help. To determine the precise accuracy of the got results of aerial surveying the checkpoint coordinates according to the orthophotomap have been set. The average square error has been calculated according to the set coordinates applying GNSS measurements. A-priori accuracy estimation of spatial coordinates of the studying territory using the aerial surveying data have been calculated: mx=0.11 m, my=0.15 m, mz=0.23 m in the village of Remeniv and mx=0.26 m, my=0.38 m, mz=0.43 m in the town of Vynnyky. The accuracy of determining checkpoint coordinates has been investigated using images obtained out of UAV and the average square error of the reference points. Based on comparative analysis of the got results of the accuracy estimation of the made orthophotomap it can be concluded that the value the average square error does not exceed a-priori accuracy estimation. The possibility of applying Trimble UX5 UAV for making large

  11. A Comparative Study of Improved Artificial Bee Colony Algorithms Applied to Multilevel Image Thresholding

    Directory of Open Access Journals (Sweden)

    Kanjana Charansiriphaisan

    2013-01-01

    Full Text Available Multilevel thresholding is a highly useful tool for the application of image segmentation. Otsu’s method, a common exhaustive search for finding optimal thresholds, involves a high computational cost. There has been a lot of recent research into various meta-heuristic searches in the area of optimization research. This paper analyses and discusses using a family of artificial bee colony algorithms, namely, the standard ABC, ABC/best/1, ABC/best/2, IABC/best/1, IABC/rand/1, and CABC, and some particle swarm optimization-based algorithms for searching multilevel thresholding. The strategy for an onlooker bee to select an employee bee was modified to serve our purposes. The metric measures, which are used to compare the algorithms, are the maximum number of function calls, successful rate, and successful performance. The ranking was performed by Friedman ranks. The experimental results showed that IABC/best/1 outperformed the other techniques when all of them were applied to multilevel image thresholding. Furthermore, the experiments confirmed that IABC/best/1 is a simple, general, and high performance algorithm.

  12. Topological Acoustics

    Science.gov (United States)

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-01

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  13. Acoustic textiles

    CERN Document Server

    Nayak, Rajkishore

    2016-01-01

    This book highlights the manufacturing and applications of acoustic textiles in various industries. It also includes examples from different industries in which acoustic textiles can be used to absorb noise and help reduce the impact of noise at the workplace. Given the importance of noise reduction in the working environment in several industries, the book offers a valuable guide for companies, educators and researchers involved with acoustic materials.

  14. Shallow Water Acoustics Studies

    Science.gov (United States)

    2017-11-19

    LE O CEAN RAPHIC I TITUTI Appli d Oc:ean Physics and E11gi1i,ering Depar1111,11t vember 9, 2017 Dr. Robert Headrick ffice of Naval Resear h, ode...UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT Applied Ocean Physics and Engineering Department...2015). [3] J.F. Lynch and A.E. Newhall, "Shallow water acoustics", book chapter in "Practical Underwater Acoustics," L. Bjorno, T. Neighbors, and D

  15. Tunable coupled surface acoustic cavities

    Science.gov (United States)

    de Lima, M. M.; Santos, P. V.; Kosevich, Yu. A.; Cantarero, A.

    2012-06-01

    We demonstrate the electric tuning of the acoustic field in acoustic microcavities (MCs) defined by a periodic arrangement of metal stripes within a surface acoustic delay line on LiNbO3 substrate. Interferometric measurements show the enhancement of the acoustic field distribution within a single MC, the presence of a "bonding" and "anti-bonding" modes for two strongly coupled MCs, as well as the positive dispersion of the "mini-bands" formed by five coupled MCs. The frequency and amplitude of the resonances can be controlled by the potential applied to the metal stripes.

  16. Imaging Apparatus And Method

    NARCIS (Netherlands)

    Manohar, Srirang; van Leeuwen, A.G.J.M.

    2010-01-01

    A thermoacoustic imaging apparatus comprises an electromagnetic radiation source configured to irradiate a sample area and an acoustic signal detection probe arrangement for detecting acoustic signals. A radiation responsive acoustic signal generator is added outside the sample area. The detection

  17. IMAGING APPARATUS AND METHOD

    NARCIS (Netherlands)

    Manohar, Srirang; van Leeuwen, A.G.J.M.

    2008-01-01

    A thermoacoustic imaging apparatus comprises an electromagnetic radiation source configured to irradiate a sample area and an acoustic signal detection probe arrangement for detecting acoustic signals. A radiation responsive acoustic signal generator is added outside the sample area. The detection

  18. Controlling Sample Rotation in Acoustic Levitation

    Science.gov (United States)

    Barmatz, M. B.; Stoneburner, J. D.

    1985-01-01

    Rotation of acoustically levitated object stopped or controlled according to phase-shift monitoring and control concept. Principle applies to square-cross-section levitation chamber with two perpendicular acoustic drivers operating at same frequency. Phase difference between X and Y acoustic excitation measured at one corner by measuring variation of acoustic amplitude sensed by microphone. Phase of driver adjusted to value that produces no rotation or controlled rotation of levitated object.

  19. Observer Evaluation of a Metal Artifact Reduction Algorithm Applied to Head and Neck Cone Beam Computed Tomographic Images

    Energy Technology Data Exchange (ETDEWEB)

    Korpics, Mark; Surucu, Murat; Mescioglu, Ibrahim; Alite, Fiori; Block, Alec M.; Choi, Mehee; Emami, Bahman; Harkenrider, Matthew M.; Solanki, Abhishek A.; Roeske, John C., E-mail: jroeske@lumc.edu

    2016-11-15

    Purpose and Objectives: To quantify, through an observer study, the reduction in metal artifacts on cone beam computed tomographic (CBCT) images using a projection-interpolation algorithm, on images containing metal artifacts from dental fillings and implants in patients treated for head and neck (H&N) cancer. Methods and Materials: An interpolation-substitution algorithm was applied to H&N CBCT images containing metal artifacts from dental fillings and implants. Image quality with respect to metal artifacts was evaluated subjectively and objectively. First, 6 independent radiation oncologists were asked to rank randomly sorted blinded images (before and after metal artifact reduction) using a 5-point rating scale (1 = severe artifacts; 5 = no artifacts). Second, the standard deviation of different regions of interest (ROI) within each image was calculated and compared with the mean rating scores. Results: The interpolation-substitution technique successfully reduced metal artifacts in 70% of the cases. From a total of 60 images from 15 H&N cancer patients undergoing image guided radiation therapy, the mean rating score on the uncorrected images was 2.3 ± 1.1, versus 3.3 ± 1.0 for the corrected images. The mean difference in ranking score between uncorrected and corrected images was 1.0 (95% confidence interval: 0.9-1.2, P<.05). The standard deviation of each ROI significantly decreased after artifact reduction (P<.01). Moreover, a negative correlation between the mean rating score for each image and the standard deviation of the oral cavity and bilateral cheeks was observed. Conclusion: The interpolation-substitution algorithm is efficient and effective for reducing metal artifacts caused by dental fillings and implants on CBCT images, as demonstrated by the statistically significant increase in observer image quality ranking and by the decrease in ROI standard deviation between uncorrected and corrected images.

  20. Comparison of infrared and 3D digital image correlation techniques applied for mechanical testing of materials

    Science.gov (United States)

    Krstulović-Opara, Lovre; Surjak, Martin; Vesenjak, Matej; Tonković, Zdenko; Kodvanj, Janoš; Domazet, Željko

    2015-11-01

    To investigate the applicability of infrared thermography as a tool for acquiring dynamic yielding in metals, a comparison of infrared thermography with three dimensional digital image correlation has been made. Dynamical tension tests and three point bending tests of aluminum alloys have been performed to evaluate results obtained by IR thermography in order to detect capabilities and limits for these two methods. Both approaches detect pastification zone migrations during the yielding process. The results of the tension test and three point bending test proved the validity of the IR approach as a method for evaluating the dynamic yielding process when used on complex structures such as cellular porous materials. The stability of the yielding process in the three point bending test, as contrary to the fluctuation of the plastification front in the tension test, is of great importance for the validation of numerical constitutive models. The research proved strong performance, robustness and reliability of the IR approach when used to evaluate yielding during dynamic loading processes, while the 3D DIC method proved to be superior in the low velocity loading regimes. This research based on two basic tests, proved the conclusions and suggestions presented in our previous research on porous materials where middle wave infrared thermography was applied.

  1. Applying deep learning technology to automatically identify metaphase chromosomes using scanning microscopic images: an initial investigation

    Science.gov (United States)

    Qiu, Yuchen; Lu, Xianglan; Yan, Shiju; Tan, Maxine; Cheng, Samuel; Li, Shibo; Liu, Hong; Zheng, Bin

    2016-03-01

    Automated high throughput scanning microscopy is a fast developing screening technology used in cytogenetic laboratories for the diagnosis of leukemia or other genetic diseases. However, one of the major challenges of using this new technology is how to efficiently detect the analyzable metaphase chromosomes during the scanning process. The purpose of this investigation is to develop a computer aided detection (CAD) scheme based on deep learning technology, which can identify the metaphase chromosomes with high accuracy. The CAD scheme includes an eight layer neural network. The first six layers compose of an automatic feature extraction module, which has an architecture of three convolution-max-pooling layer pairs. The 1st, 2nd and 3rd pair contains 30, 20, 20 feature maps, respectively. The seventh and eighth layers compose of a multiple layer perception (MLP) based classifier, which is used to identify the analyzable metaphase chromosomes. The performance of new CAD scheme was assessed by receiver operation characteristic (ROC) method. A number of 150 regions of interest (ROIs) were selected to test the performance of our new CAD scheme. Each ROI contains either interphase cell or metaphase chromosomes. The results indicate that new scheme is able to achieve an area under the ROC curve (AUC) of 0.886+/-0.043. This investigation demonstrates that applying a deep learning technique may enable to significantly improve the accuracy of the metaphase chromosome detection using a scanning microscopic imaging technology in the future.

  2. Acoustic agglomeration methods and apparatus

    Science.gov (United States)

    Barmatz, M. B. (Inventor)

    1984-01-01

    Methods are described for using acoustic energy to agglomerate fine particles on the order of one micron diameter that are suspended in gas, to provide agglomerates large enough for efficient removal by other techniques. The gas with suspended particles, is passed through the length of a chamber while acoustic energy at a resonant chamber mode is applied to set up one or more acoustic standing wave patterns that vibrate the suspended particles to bring them together so they agglomerate. Several widely different frequencies can be applied to efficiently vibrate particles of widely differing sizes. The standing wave pattern can be applied along directions transversed to the flow of the gas. The particles can be made to move in circles by applying acoustic energy in perpendicular directions with the energy in both directions being of the same wavelength but 90 deg out of phase.

  3. TH-EF-207A-05: Feasibility of Applying SMEIR Method On Small Animal 4D Cone Beam CT Imaging

    International Nuclear Information System (INIS)

    Zhong, Y; Zhang, Y; Shao, Y; Wang, J

    2016-01-01

    Purpose: Small animal cone beam CT imaging has been widely used in preclinical research. Due to the higher respiratory rate and heat beats of small animals, motion blurring is inevitable and needs to be corrected in the reconstruction. Simultaneous motion estimation and image reconstruction (SMEIR) method, which uses projection images of all phases, proved to be effective in motion model estimation and able to reconstruct motion-compensated images. We demonstrate the application of SMEIR for small animal 4D cone beam CT imaging by computer simulations on a digital rat model. Methods: The small animal CBCT imaging system was simulated with the source-to-detector distance of 300 mm and the source-to-object distance of 200 mm. A sequence of rat phantom were generated with 0.4 mm 3 voxel size. The respiratory cycle was taken as 1.0 second and the motions were simulated with a diaphragm motion of 2.4mm and an anterior-posterior expansion of 1.6 mm. The projection images were calculated using a ray-tracing method, and 4D-CBCT were reconstructed using SMEIR and FDK methods. The SMEIR method iterates over two alternating steps: 1) motion-compensated iterative image reconstruction by using projections from all respiration phases and 2) motion model estimation from projections directly through a 2D-3D deformable registration of the image obtained in the first step to projection images of other phases. Results: The images reconstructed using SMEIR method reproduced the features in the original phantom. Projections from the same phase were also reconstructed using FDK method. Compared with the FDK results, the images from SMEIR method substantially improve the image quality with minimum artifacts. Conclusion: We demonstrate that it is viable to apply SMEIR method to reconstruct small animal 4D-CBCT images.

  4. Acoustic phenomena during boiling

    International Nuclear Information System (INIS)

    Dorofeev, B.M.

    1985-01-01

    Applied and theoretical significance of investigation into acoustic phenomena on boiling is discussed. Effect of spatial and time conditions on pressure vapour bubble has been elucidated. Collective effects were considered: acoustic interaction of bubbles, noise formation ion developed boiling, resonance and hydrodynamic autooscillations. Different methods for predicting heat transfer crisis using changes of accompanying noise characteristics were analysed. Principle peculiarities of generation mechanism of thermoacoustic autooscillations were analysed as well: formation of standing waves; change of two-phase medium contraction in a channel; relation of alternating pressure with boiling process as well as with instantaneous and local temperatures of heat transfer surface and liquid in a boundary layer

  5. Acoustic emission intrusion detector

    International Nuclear Information System (INIS)

    Carver, D.W.; Whittaker, J.W.

    1980-01-01

    An intrusion detector is provided for detecting a forcible entry into a secured structure while minimizing false alarms. The detector uses a piezoelectric crystal transducer to sense acoustic emissions. The transducer output is amplified by a selectable gain amplifier to control the sensitivity. The rectified output of the amplifier is applied to a Schmitt trigger circuit having a preselected threshold level to provide amplitude discrimination. Timing circuitry is provided which is activated by successive pulses from the Schmitt trigger which lie within a selected time frame for frequency discrimination. Detected signals having proper amplitude and frequency trigger an alarm within the first complete cycle time of a detected acoustical disturbance signal

  6. Magnetoactive Acoustic Metamaterials.

    Science.gov (United States)

    Yu, Kunhao; Fang, Nicholas X; Huang, Guoliang; Wang, Qiming

    2018-04-11

    Acoustic metamaterials with negative constitutive parameters (modulus and/or mass density) have shown great potential in diverse applications ranging from sonic cloaking, abnormal refraction and superlensing, to noise canceling. In conventional acoustic metamaterials, the negative constitutive parameters are engineered via tailored structures with fixed geometries; therefore, the relationships between constitutive parameters and acoustic frequencies are typically fixed to form a 2D phase space once the structures are fabricated. Here, by means of a model system of magnetoactive lattice structures, stimuli-responsive acoustic metamaterials are demonstrated to be able to extend the 2D phase space to 3D through rapidly and repeatedly switching signs of constitutive parameters with remote magnetic fields. It is shown for the first time that effective modulus can be reversibly switched between positive and negative within controlled frequency regimes through lattice buckling modulated by theoretically predicted magnetic fields. The magnetically triggered negative-modulus and cavity-induced negative density are integrated to achieve flexible switching between single-negative and double-negative. This strategy opens promising avenues for remote, rapid, and reversible modulation of acoustic transportation, refraction, imaging, and focusing in subwavelength regimes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    OpenAIRE

    Liang, Zhengzhao; Liu, Xiangxin; Zhang, Yanbo; Tang, Chunan

    2013-01-01

    To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE) and far infrared (FIR) techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE wa...

  8. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array

    Science.gov (United States)

    Zhou, Li

    2018-01-01

    This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method. PMID:29466310

  9. An Optimal Image-Based Method for Identification of Acoustic Emission (AE) Sources in Plate-Like Structures Using a Lead Zirconium Titanate (PZT) Sensor Array.

    Science.gov (United States)

    Yan, Gang; Zhou, Li

    2018-02-21

    This paper proposes an innovative method for identifying the locations of multiple simultaneous acoustic emission (AE) events in plate-like structures from the view of image processing. By using a linear lead zirconium titanate (PZT) sensor array to record the AE wave signals, a reverse-time frequency-wavenumber (f-k) migration is employed to produce images displaying the locations of AE sources by back-propagating the AE waves. Lamb wave theory is included in the f-k migration to consider the dispersive property of the AE waves. Since the exact occurrence time of the AE events is usually unknown when recording the AE wave signals, a heuristic artificial bee colony (ABC) algorithm combined with an optimal criterion using minimum Shannon entropy is used to find the image with the identified AE source locations and occurrence time that mostly approximate the actual ones. Experimental studies on an aluminum plate with AE events simulated by PZT actuators are performed to validate the applicability and effectiveness of the proposed optimal image-based AE source identification method.

  10. Assessment of Atmospheric Correction Methods for Sentinel-2 MSI Images Applied to Amazon Floodplain Lakes

    Directory of Open Access Journals (Sweden)

    Vitor Souza Martins

    2017-03-01

    Full Text Available Satellite data provide the only viable means for extensive monitoring of remote and large freshwater systems, such as the Amazon floodplain lakes. However, an accurate atmospheric correction is required to retrieve water constituents based on surface water reflectance ( R W . In this paper, we assessed three atmospheric correction methods (Second Simulation of a Satellite Signal in the Solar Spectrum (6SV, ACOLITE and Sen2Cor applied to an image acquired by the MultiSpectral Instrument (MSI on-board of the European Space Agency’s Sentinel-2A platform using concurrent in-situ measurements over four Amazon floodplain lakes in Brazil. In addition, we evaluated the correction of forest adjacency effects based on the linear spectral unmixing model, and performed a temporal evaluation of atmospheric constituents from Multi-Angle Implementation of Atmospheric Correction (MAIAC products. The validation of MAIAC aerosol optical depth (AOD indicated satisfactory retrievals over the Amazon region, with a correlation coefficient (R of ~0.7 and 0.85 for Terra and Aqua products, respectively. The seasonal distribution of the cloud cover and AOD revealed a contrast between the first and second half of the year in the study area. Furthermore, simulation of top-of-atmosphere (TOA reflectance showed a critical contribution of atmospheric effects (>50% to all spectral bands, especially the deep blue (92%–96% and blue (84%–92% bands. The atmospheric correction results of the visible bands illustrate the limitation of the methods over dark lakes ( R W < 1%, and better match of the R W shape compared with in-situ measurements over turbid lakes, although the accuracy varied depending on the spectral bands and methods. Particularly above 705 nm, R W was highly affected by Amazon forest adjacency, and the proposed adjacency effect correction minimized the spectral distortions in R W (RMSE < 0.006. Finally, an extensive validation of the methods is required for

  11. Battlefield acoustics

    CERN Document Server

    Damarla, Thyagaraju

    2015-01-01

    This book presents all aspects of situational awareness in a battlefield using acoustic signals. It starts by presenting the science behind understanding and interpretation of sound signals. The book then goes on to provide various signal processing techniques used in acoustics to find the direction of sound source, localize gunfire, track vehicles, and detect people. The necessary mathematical background and various classification and fusion techniques are presented. The book contains majority of the things one would need to process acoustic signals for all aspects of situational awareness in one location. The book also presents array theory, which is pivotal in finding the direction of arrival of acoustic signals. In addition, the book presents techniques to fuse the information from multiple homogeneous/heterogeneous sensors for better detection. MATLAB code is provided for majority of the real application, which is a valuable resource in not only understanding the theory but readers, can also use the code...

  12. Acoustics Research

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fisheries acoustics data are collected from more than 200 sea-days each year aboard the FRV DELAWARE II and FRV ALBATROSS IV (decommissioned) and the FSV Henry B....

  13. Room Acoustics

    Science.gov (United States)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  14. Acoustics waves and oscillations

    CERN Document Server

    Sen, S.N.

    2013-01-01

    Parameters of acoustics presented in a logical and lucid style Physical principles discussed with mathematical formulations Importance of ultrasonic waves highlighted Dispersion of ultrasonic waves in viscous liquids explained This book presents the theory of waves and oscillations and various applications of acoustics in a logical and simple form. The physical principles have been explained with necessary mathematical formulation and supported by experimental layout wherever possible. Incorporating the classical view point all aspects of acoustic waves and oscillations have been discussed together with detailed elaboration of modern technological applications of sound. A separate chapter on ultrasonics emphasizes the importance of this branch of science in fundamental and applied research. In this edition a new chapter ''Hypersonic Velocity in Viscous Liquids as revealed from Brillouin Spectra'' has been added. The book is expected to present to its readers a comprehensive presentation of the subject matter...

  15. Experiments for possible hydroacoustic discrimination of free-swimming juvenile gadoid fish by analysis of broadband pulse spectra as well as 3D fish position form video images and split beam acoustics

    DEFF Research Database (Denmark)

    Lundgren, Bo; Nielsen, J. Rasmus

    2002-01-01

    , alignment of acoustic and optical-reference frames, and automatic position-fitting of fish models to manually marked fix-points on fish images. The software also performs Fourier spectrum analysis and pulse-shape analysis of broad-bandwidth echoes. Therefore, several measurement series on free...

  16. Using wavelet denoising and mathematical morphology in the segmentation technique applied to blood cells images

    OpenAIRE

    Boix García, Macarena; Cantó Colomina, Begoña

    2013-01-01

    Accurate image segmentation is used in medical diagnosis since this technique is a noninvasive pre-processing step for biomedical treatment. In this work we present an efficient segmentation method for medical image analysis. In particular, with this method blood cells can be segmented. For that, we combine the wavelet transform with morphological operations. Moreover, the wavelet thresholding technique is used to eliminate the noise and prepare the image for suitable segmentation. In wavelet...

  17. Digital image correlation, acoustic emission and ultrasonic pulse velocity for the detection of cracks in the concrete buffer of the Belgian nuclear supercontainer

    International Nuclear Information System (INIS)

    Iliopoulos, Sokratis; Tsangouri, Eleni; Aggelis, Dimitrios G.; Pyl, Lincy; Areias, Lou; Vrije Univ., Brussels

    2014-01-01

    The long term management of high-level and heat emitting radioactive waste is a worldwide concern, as it directly influences the environment and future generations. To address this issue, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials has come up with the conceptual design of a massive concrete structure called Supercontainer. The feasibility to construct these structures is being evaluated through a number of scaled models that are tested using classical as well as state of the art measurement techniques. In the current paper, the results obtained from the simultaneous application of the Digital Image Correlation (DIC), the Acoustic Emission (AE) and the Ultrasonic Pulse Velocity (UPV) nondestructive testing techniques on the second scaled model for the detection and monitoring of cracks will be presented.

  18. MRI of acoustic neurinoma

    International Nuclear Information System (INIS)

    Matsumoto, Kunihiko; Niitsu, Mamoru; Yoshioka, Hiroshi; Tanaka, Yumiko; Anno, Izumi; Kuramoto, Kenmei; Itai, Yuji

    1994-01-01

    Thirty six patients were studied with a 1.5 T superconductive magnetic resonance imager. Small neurinomas appeared as homogenous intensities, large neurinomas as heterogenous intensities in T 1 and T 2 weighted images. Dural tail representing reactive change of the meninges was seen in our three acoustic neurinomas. High resolution, thin slice, MR imaging was particularly useful for intracanalicular tumor to see the relationship between the tumor and facial nerve. Total or near-total removal of tumor was performed in thirteen cases, in which functional preservation of the cochlear nerve was achieved in only three cases. (author)

  19. 3D Coda Attenuation Tomography of Acoustic Emission Data from Laboratory Samples as a tool for imaging pre-failure deformation mechanisms

    Science.gov (United States)

    Vinciguerra, S.; King, T. I.; Benson, P. M.; De Siena, L.

    2017-12-01

    In recent years, 3D and 4D seismic tomography have unraveled medium changes during the seismic cycle or before eruptive events. As our resolving power increases, however, complex structures increasingly affect images. Being able to interpret and understand these features requires a multi-discipline approach combining different methods, each sensitive to particular properties of the sub-surface. Rock deformation laboratory experiments can relate seismic properties to the evolving medium quantitatively. Here, an array of 1 MHz Piezo-Electric Transducers has recorded high-quality low-noise acoustic emission (AE) data during triaxial compressional experiments. Samples of Carrara Marble, Darley Dale Sandstone and Westerly Granite were deformed in saturated conditions representative of a depth of about 1 km until brittle failure. Using a time window around sample failure, AE data were filtered between 5 and 75 KHz and processed using a 3D P-coda attenuation-tomography method. Ratios of P-direct to P-coda energies calculated for each source-receiver path were inverted using the coda normalisation method for values of Q (P-wave quality factor). The results show Q-variation with respect to an average Q. Q is a combination of the effects of scattering attenuation (Qs) and intrinsic attenuation Q (Qi), which can be correlated to the sample structure. Qs primary controls energy dissipation in the presence at acoustic impedance (AI) surfaces and at fracture tips, independently of rock type, while pore fluid effects dissipate energy (Qi). Damaged zones appear as high-Q and low-Q anomalies in unsaturated and saturated samples, respectively. We have attributed frequency-dependent high-Q to resonance in the presence of AI surfaces. Low Q areas appear behind AI surfaces and are interpreted as energy shadows. These shadows can affect attenuation tomography imaging at field scale.

  20. 4-D imaging of seepage in earthen embankments with time-lapse inversion of self-potential data constrained by acoustic emissions localization

    Science.gov (United States)

    Rittgers, J. B.; Revil, A.; Planes, T.; Mooney, M. A.; Koelewijn, A. R.

    2015-02-01

    New methods are required to combine the information contained in the passive electrical and seismic signals to detect, localize and monitor hydromechanical disturbances in porous media. We propose a field experiment showing how passive seismic and electrical data can be combined together to detect a preferential flow path associated with internal erosion in a Earth dam. Continuous passive seismic and electrical (self-potential) monitoring data were recorded during a 7-d full-scale levee (earthen embankment) failure test, conducted in Booneschans, Netherlands in 2012. Spatially coherent acoustic emissions events and the development of a self-potential anomaly, associated with induced concentrated seepage and internal erosion phenomena, were identified and imaged near the downstream toe of the embankment, in an area that subsequently developed a series of concentrated water flows and sand boils, and where liquefaction of the embankment toe eventually developed. We present a new 4-D grid-search algorithm for acoustic emissions localization in both time and space, and the application of the localization results to add spatially varying constraints to time-lapse 3-D modelling of self-potential data in the terms of source current localization. Seismic signal localization results are utilized to build a set of time-invariant yet spatially varying model weights used for the inversion of the self-potential data. Results from the combination of these two passive techniques show results that are more consistent in terms of focused ground water flow with respect to visual observation on the embankment. This approach to geophysical monitoring of earthen embankments provides an improved approach for early detection and imaging of the development of embankment defects associated with concentrated seepage and internal erosion phenomena. The same approach can be used to detect various types of hydromechanical disturbances at larger scales.

  1. A resolution adaptive deep hierarchical (RADHicaL) learning scheme applied to nuclear segmentation of digital pathology images.

    Science.gov (United States)

    Janowczyk, Andrew; Doyle, Scott; Gilmore, Hannah; Madabhushi, Anant

    2018-01-01

    Deep learning (DL) has recently been successfully applied to a number of image analysis problems. However, DL approaches tend to be inefficient for segmentation on large image data, such as high-resolution digital pathology slide images. For example, typical breast biopsy images scanned at 40× magnification contain billions of pixels, of which usually only a small percentage belong to the class of interest. For a typical naïve deep learning scheme, parsing through and interrogating all the image pixels would represent hundreds if not thousands of hours of compute time using high performance computing environments. In this paper, we present a resolution adaptive deep hierarchical (RADHicaL) learning scheme wherein DL networks at lower resolutions are leveraged to determine if higher levels of magnification, and thus computation, are necessary to provide precise results. We evaluate our approach on a nuclear segmentation task with a cohort of 141 ER+ breast cancer images and show we can reduce computation time on average by about 85%. Expert annotations of 12,000 nuclei across these 141 images were employed for quantitative evaluation of RADHicaL. A head-to-head comparison with a naïve DL approach, operating solely at the highest magnification, yielded the following performance metrics: .9407 vs .9854 Detection Rate, .8218 vs .8489 F -score, .8061 vs .8364 true positive rate and .8822 vs 0.8932 positive predictive value. Our performance indices compare favourably with state of the art nuclear segmentation approaches for digital pathology images.

  2. Applying machine learning and image feature extraction techniques to the problem of cerebral aneurysm rupture

    Directory of Open Access Journals (Sweden)

    Steren Chabert

    2017-01-01

    Full Text Available Cerebral aneurysm is a cerebrovascular disorder characterized by a bulging in a weak area in the wall of an artery that supplies blood to the brain. It is relevant to understand the mechanisms leading to the apparition of aneurysms, their growth and, more important, leading to their rupture. The purpose of this study is to study the impact on aneurysm rupture of the combination of different parameters, instead of focusing on only one factor at a time as is frequently found in the literature, using machine learning and feature extraction techniques. This discussion takes relevance in the context of the complex decision that the physicians have to take to decide which therapy to apply, as each intervention bares its own risks, and implies to use a complex ensemble of resources (human resources, OR, etc. in hospitals always under very high work load. This project has been raised in our actual working team, composed of interventional neuroradiologist, radiologic technologist, informatics engineers and biomedical engineers, from Valparaiso public Hospital, Hospital Carlos van Buren, and from Universidad de Valparaíso – Facultad de Ingeniería and Facultad de Medicina. This team has been working together in the last few years, and is now participating in the implementation of an “interdisciplinary platform for innovation in health”, as part of a bigger project leaded by Universidad de Valparaiso (PMI UVA1402. It is relevant to emphasize that this project is made feasible by the existence of this network between physicians and engineers, and by the existence of data already registered in an orderly manner, structured and recorded in digital format. The present proposal arises from the description in nowadays literature that the actual indicators, whether based on morphological description of the aneurysm, or based on characterization of biomechanical factor or others, these indicators were shown not to provide sufficient information in order

  3. Digital processing methodology applied to exploring of radiological images; Metodologia de processamento digital aplicada a exploracao de imagens radiologicas

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cristiane de Queiroz

    2004-07-01

    In this work, digital image processing is applied as a automatic computational method, aimed for exploring of radiological images. It was developed an automatic routine, from the segmentation and post-processing techniques to the radiology images acquired from an arrangement, consisting of a X-ray tube, target and filter of molybdenum, of 0.4 mm and 0.03 mm, respectively, and CCD detector. The efficiency of the methodology developed is showed in this work, through a case study, where internal injuries in mangoes are automatically detected and monitored. This methodology is a possible tool to be introduced in the post-harvest process in packing houses. A dichotomic test was applied to evaluate a efficiency of the method. The results show a success of 87.7% to correct diagnosis and 12.3% to failures to correct diagnosis with a sensibility of 93% and specificity of 80%. (author)

  4. Elimination of image flicker in a fringe-field switching liquid crystal display by applying a bipolar voltage wave.

    Science.gov (United States)

    Oh, Seung-Won; Park, Jun-Hee; Lee, Ji-Hoon; Yoon, Tae-Hoon

    2015-09-07

    Recently, low-frequency driving of liquid crystal display (LCD) panels to minimize power consumption has drawn much attention. In the case in which an LCD panel is driven by a fringe-field at a low frequency, the image flickering phenomenon occurs when the sign of the applied electric field is reversed. We investigated image flickering induced by the flexoelectric effect in a fringe-field switching (FFS) liquid crystal cell in terms of the transmittance difference between frames and the ripple phenomenon. Experimental results show that image flicker due to transmittance difference can be eliminated completely and that the ripple phenomena can be reduced significantly by applying a bipolar voltage wave to the FFS cell.

  5. Probabilistic Multiple-Bias Modeling Applied to the Canadian Data From the Interphone Study of Mobile Phone Use and Risk of Glioma, Meningioma, Acoustic Neuroma, and Parotid Gland Tumors.

    Science.gov (United States)

    Momoli, F; Siemiatycki, J; McBride, M L; Parent, M-É; Richardson, L; Bedard, D; Platt, R; Vrijheid, M; Cardis, E; Krewski, D

    2017-10-01

    We undertook a re-analysis of the Canadian data from the 13-country case-control Interphone Study (2001-2004), in which researchers evaluated the associations of mobile phone use with the risks of brain, acoustic neuroma, and parotid gland tumors. In the main publication of the multinational Interphone Study, investigators concluded that biases and errors prevented a causal interpretation. We applied a probabilistic multiple-bias model to address possible biases simultaneously, using validation data from billing records and nonparticipant questionnaires as information on recall error and selective participation. In our modeling, we sought to adjust for these sources of uncertainty and to facilitate interpretation. For glioma, when comparing those in the highest quartile of use (>558 lifetime hours) to those who were not regular users, the odds ratio was 2.0 (95% confidence interval: 1.2, 3.4). After adjustment for selection and recall biases, the odds ratio was 2.2 (95% limits: 1.3, 4.1). There was little evidence of an increase in the risk of meningioma, acoustic neuroma, or parotid gland tumors in relation to mobile phone use. Adjustments for selection and recall biases did not materially affect interpretation in our results from Canadian data. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. VisualRank: applying PageRank to large-scale image search.

    Science.gov (United States)

    Jing, Yushi; Baluja, Shumeet

    2008-11-01

    Because of the relative ease in understanding and processing text, commercial image-search systems often rely on techniques that are largely indistinguishable from text-search. Recently, academic studies have demonstrated the effectiveness of employing image-based features to provide alternative or additional signals. However, it remains uncertain whether such techniques will generalize to a large number of popular web queries, and whether the potential improvement to search quality warrants the additional computational cost. In this work, we cast the image-ranking problem into the task of identifying "authority" nodes on an inferred visual similarity graph and propose VisualRank to analyze the visual link structures among images. The images found to be "authorities" are chosen as those that answer the image-queries well. To understand the performance of such an approach in a real system, we conducted a series of large-scale experiments based on the task of retrieving images for 2000 of the most popular products queries. Our experimental results show significant improvement, in terms of user satisfaction and relevancy, in comparison to the most recent Google Image Search results. Maintaining modest computational cost is vital to ensuring that this procedure can be used in practice; we describe the techniques required to make this system practical for large scale deployment in commercial search engines.

  7. Segment and fit thresholding: a new method for image analysis applied to microarray and immunofluorescence data.

    Science.gov (United States)

    Ensink, Elliot; Sinha, Jessica; Sinha, Arkadeep; Tang, Huiyuan; Calderone, Heather M; Hostetter, Galen; Winter, Jordan; Cherba, David; Brand, Randall E; Allen, Peter J; Sempere, Lorenzo F; Haab, Brian B

    2015-10-06

    Experiments involving the high-throughput quantification of image data require algorithms for automation. A challenge in the development of such algorithms is to properly interpret signals over a broad range of image characteristics, without the need for manual adjustment of parameters. Here we present a new approach for locating signals in image data, called Segment and Fit Thresholding (SFT). The method assesses statistical characteristics of small segments of the image and determines the best-fit trends between the statistics. Based on the relationships, SFT identifies segments belonging to background regions; analyzes the background to determine optimal thresholds; and analyzes all segments to identify signal pixels. We optimized the initial settings for locating background and signal in antibody microarray and immunofluorescence data and found that SFT performed well over multiple, diverse image characteristics without readjustment of settings. When used for the automated analysis of multicolor, tissue-microarray images, SFT correctly found the overlap of markers with known subcellular localization, and it performed better than a fixed threshold and Otsu's method for selected images. SFT promises to advance the goal of full automation in image analysis.

  8. Applying a computer-aided scheme to detect a new radiographic image marker for prediction of chemotherapy outcome

    International Nuclear Information System (INIS)

    Wang, Yunzhi; Qiu, Yuchen; Thai, Theresa; Moore, Kathleen; Liu, Hong; Zheng, Bin

    2016-01-01

    To investigate the feasibility of automated segmentation of visceral and subcutaneous fat areas from computed tomography (CT) images of ovarian cancer patients and applying the computed adiposity-related image features to predict chemotherapy outcome. A computerized image processing scheme was developed to segment visceral and subcutaneous fat areas, and compute adiposity-related image features. Then, logistic regression models were applied to analyze association between the scheme-generated assessment scores and progression-free survival (PFS) of patients using a leave-one-case-out cross-validation method and a dataset involving 32 patients. The correlation coefficients between automated and radiologist’s manual segmentation of visceral and subcutaneous fat areas were 0.76 and 0.89, respectively. The scheme-generated prediction scores using adiposity-related radiographic image features significantly associated with patients’ PFS (p < 0.01). Using a computerized scheme enables to more efficiently and robustly segment visceral and subcutaneous fat areas. The computed adiposity-related image features also have potential to improve accuracy in predicting chemotherapy outcome

  9. Parameters and definitions in applied technique quality test for nuclear magnetic resonance imaging system (NMRI)

    International Nuclear Information System (INIS)

    Lin Zhikai; Zhao Lancai

    1999-08-01

    During the past two decades, medical diagnostic imaging technique has achieved dramatic development such as CT, MRI, PET, DSA and so on. The most striking examples of them are the application of X ray computerized tomography (CT) and magnetic resonance imaging in the field of medical diagnosis. It can be predicted that magnetic resonance imaging (MRI) will definitely have more widespread prospects of applications and play more and more important role in clinical diagnosis looking forward to the development of image diagnostic technique for 21 st century. The authors also present the measuring methods for some parameters. The parameters described can be used for reference by clinical diagnosticians, operators on MRI and medical physicists who engages in image quality assurance (QA) and control (QC) in performing MRI acceptance test and routine test

  10. Applied high-speed imaging for the icing research program at NASA Lewis Research Center

    Science.gov (United States)

    Slater, Howard; Owens, Jay; Shin, Jaiwon

    1992-01-01

    The Icing Research Tunnel at NASA Lewis Research Center provides scientists a scaled, controlled environment to simulate natural icing events. The closed-loop, low speed, refrigerated wind tunnel offers the experimental capability to test for icing certification requirements, analytical model validation and calibration techniques, cloud physics instrumentation refinement, advanced ice protection systems, and rotorcraft icing methodology development. The test procedures for these objectives all require a high degree of visual documentation, both in real-time data acquisition and post-test image processing. Information is provided to scientific, technical, and industrial imaging specialists as well as to research personnel about the high-speed and conventional imaging systems will be on the recent ice protection technology program. Various imaging examples for some of the tests are presented. Additional imaging examples are available from the NASA Lewis Research Center's Photographic and Printing Branch.

  11. Applying Support Vector Machine in classifying satellite images for the assessment of urban sprawl

    Science.gov (United States)

    murgante, Beniamino; Nolè, Gabriele; Lasaponara, Rosa; Lanorte, Antonio; Calamita, Giuseppe

    2013-04-01

    In last decades the spreading of new buildings, road infrastructures and a scattered proliferation of houses in zones outside urban areas, produced a countryside urbanization with no rules, consuming soils and impoverishing the landscape. Such a phenomenon generated a huge environmental impact, diseconomies and a decrease in life quality. This study analyzes processes concerning land use change, paying particular attention to urban sprawl phenomenon. The application is based on the integration of Geographic Information Systems and Remote Sensing adopting open source technologies. The objective is to understand size distribution and dynamic expansion of urban areas in order to define a methodology useful to both identify and monitor the phenomenon. In order to classify "urban" pixels, over time monitoring of settlements spread, understanding trends of artificial territories, classifications of satellite images at different dates have been realized. In order to obtain these classifications, supervised classification algorithms have been adopted. More particularly, Support Vector Machine (SVM) learning algorithm has been applied to multispectral remote data. One of the more interesting features in SVM is the possibility to obtain good results also adopting few classification pixels of training areas. SVM has several interesting features, such as the capacity to obtain good results also adopting few classification pixels of training areas, a high possibility of configuration parameters and the ability to discriminate pixels with similar spectral responses. Multi-temporal ASTER satellite data at medium resolution have been adopted because are very suitable in evaluating such phenomena. The application is based on the integration of Geographic Information Systems and Remote Sensing technologies by means of open source software. Tools adopted in managing and processing data are GRASS GIS, Quantum GIS and R statistical project. The area of interest is located south of Bari

  12. Automated striatal uptake analysis of 18F-FDOPA PET images applied to Parkinson's disease patients

    International Nuclear Information System (INIS)

    Chang Icheng; Lue Kunhan; Hsieh Hungjen; Liu Shuhsin; Kao, Chinhao K.

    2011-01-01

    6-[ 18 F]Fluoro-L-DOPA (FDOPA) is a radiopharmaceutical valuable for assessing the presynaptic dopaminergic function when used with positron emission tomography (PET). More specifically, the striatal-to-occipital ratio (SOR) of FDOPA uptake images has been extensively used as a quantitative parameter in these PET studies. Our aim was to develop an easy, automated method capable of performing objective analysis of SOR in FDOPA PET images of Parkinson's disease (PD) patients. Brain images from FDOPA PET studies of 21 patients with PD and 6 healthy subjects were included in our automated striatal analyses. Images of each individual were spatially normalized into an FDOPA template. Subsequently, the image slice with the highest level of basal ganglia activity was chosen among the series of normalized images. Also, the immediate preceding and following slices of the chosen image were then selected. Finally, the summation of these three images was used to quantify and calculate the SOR values. The results obtained by automated analysis were compared with manual analysis by a trained and experienced image processing technologist. The SOR values obtained from the automated analysis had a good agreement and high correlation with manual analysis. The differences in caudate, putamen, and striatum were -0.023, -0.029, and -0.025, respectively; correlation coefficients 0.961, 0.957, and 0.972, respectively. We have successfully developed a method for automated striatal uptake analysis of FDOPA PET images. There was no significant difference between the SOR values obtained from this method and using manual analysis. Yet it is an unbiased time-saving and cost-effective program and easy to implement on a personal computer. (author)

  13. A new deconvolution method applied to ultrasonic images; Etude d'une methode de deconvolution adaptee aux images ultrasonores

    Energy Technology Data Exchange (ETDEWEB)

    Sallard, J

    1999-07-01

    This dissertation presents the development of a new method for restoration of ultrasonic signals. Our goal is to remove the perturbations induced by the ultrasonic probe and to help to characterize the defects due to a strong local discontinuity of the acoustic impedance. The point of view adopted consists in taking into account the physical properties in the signal processing to develop an algorithm which gives good results even on experimental data. The received ultrasonic signal is modeled as a convolution between a function that represents the waveform emitted by the transducer and a function that is abusively called the 'defect impulse response'. It is established that, in numerous cases, the ultrasonic signal can be expressed as a sum of weighted, phase-shifted replicas of a reference signal. Deconvolution is an ill-posed problem. A priori information must be taken into account to solve the problem. The a priori information translates the physical properties of the ultrasonic signals. The defect impulse response is modeled as a Double-Bernoulli-Gaussian sequence. Deconvolution becomes the problem of detection of the optimal Bernoulli sequence and estimation of the associated complex amplitudes. Optimal parameters of the sequence are those which maximize a likelihood function. We develop a new estimation procedure based on an optimization process. An adapted initialization procedure and an iterative algorithm enables to quickly process a huge number of data. Many experimental ultrasonic data that reflect usual control configurations have been processed and the results demonstrate the robustness of the method. Our algorithm enables not only to remove the waveform emitted by the transducer but also to estimate the phase. This parameter is useful for defect characterization. At last the algorithm makes easier data interpretation by concentrating information. So automatic characterization should be possible in the future. (author)

  14. A single-sided homogeneous Green's function representation for holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval

    Science.gov (United States)

    Wapenaar, Kees; Thorbecke, Jan; van der Neut, Joost

    2016-04-01

    Green's theorem plays a fundamental role in a diverse range of wavefield imaging applications, such as holographic imaging, inverse scattering, time-reversal acoustics and interferometric Green's function retrieval. In many of those applications, the homogeneous Green's function (i.e. the Green's function of the wave equation without a singularity on the right-hand side) is represented by a closed boundary integral. In practical applications, sources and/or receivers are usually present only on an open surface, which implies that a significant part of the closed boundary integral is by necessity ignored. Here we derive a homogeneous Green's function representation for the common situation that sources and/or receivers are present on an open surface only. We modify the integrand in such a way that it vanishes on the part of the boundary where no sources and receivers are present. As a consequence, the remaining integral along the open surface is an accurate single-sided representation of the homogeneous Green's function. This single-sided representation accounts for all orders of multiple scattering. The new representation significantly improves the aforementioned wavefield imaging applications, particularly in situations where the first-order scattering approximation breaks down.

  15. System and method to create three-dimensional images of non-linear acoustic properties in a region remote from a borehole

    Science.gov (United States)

    Vu, Cung; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Christopher; Johnson, Paul A.; Guyer, Robert; TenCate, James A.; Le Bas, Pierre-Yves

    2013-01-01

    In some aspects of the disclosure, a method for creating three-dimensional images of non-linear properties and the compressional to shear velocity ratio in a region remote from a borehole using a conveyed logging tool is disclosed. In some aspects, the method includes arranging a first source in the borehole and generating a steered beam of elastic energy at a first frequency; arranging a second source in the borehole and generating a steerable beam of elastic energy at a second frequency, such that the steerable beam at the first frequency and the steerable beam at the second frequency intercept at a location away from the borehole; receiving at the borehole by a sensor a third elastic wave, created by a three wave mixing process, with a frequency equal to a difference between the first and second frequencies and a direction of propagation towards the borehole; determining a location of a three wave mixing region based on the arrangement of the first and second sources and on properties of the third wave signal; and creating three-dimensional images of the non-linear properties using data recorded by repeating the generating, receiving and determining at a plurality of azimuths, inclinations and longitudinal locations within the borehole. The method is additionally used to generate three dimensional images of the ratio of compressional to shear acoustic velocity of the same volume surrounding the borehole.

  16. Acoustic Emission Technology and Application

    International Nuclear Information System (INIS)

    Joo, Y. S.; Lim, S. H.; Eom, H. S.; Kim, J. H.; Jung, H. K.

    2003-10-01

    Acoustic emission is the elastic wave that is generated by the rapid release of energy from the localized sources within a material. After the observation of acoustic emission phenomenon in 1950, the research and further investigation had been performed. Acoustic emission examination becomes a rapidly matured nondestructive testing method with demonstrated capabilities for characterizing material behavior and for detecting the defect. It is of interest as a possible passive monitoring technique for detecting, locating and characterizing the defects in component and structure. Acoustic emission technology has recently strengthened the on-line monitoring application for the detection of incipient failures and the assurance of structural integrity. The field of acoustic emission testing is still growing vigorously and presents many challenges. Especially, acoustic emission has been successfully applied in the leak detection of primary pressure boundary of nuclear power plants. In this state-of-art report, the principle, measurement and field applications of acoustic emission technique is reviewed and summarized. Acoustic emission technology will contribute to the assurance of nuclear safety as the on-line monitoring technique of structural integrity of NSSS components and structures

  17. Evaluation of the influence of acquisition parameters of microtomography in image quality applied by carbonate rocks

    Science.gov (United States)

    Santos, T. M. P.; Machado, A. S.; Araújo, O. M. O.; Ferreira, C. G.; Lopes, R. T.

    2018-03-01

    X-ray computed microtomography is a powerful nondestructive technique for 2D and 3D structure analysis. However, parameters used in acquisition promote directs influence in qualitative and quantitative results in characterization of samples, due image resolution. The aim of this study is value the influence of theses parameters in results through of tests changing these parameters in different situations and system characterization. Results demonstrate those pixel size and detector matrixes are the main parameters that influence in resolution and image quality. Microtomography was considered an excellent technique for characterization using the best image resolution possible.

  18. Applying Data-driven Imaging Biomarker in Mammography for Breast Cancer Screening: Preliminary Study

    OpenAIRE

    Kim, Eun-Kyung; Kim, Hyo-Eun; Han, Kyunghwa; Kang, Bong Joo; Sohn, Yu-Mee; Woo, Ok Hee; Lee, Chan Wha

    2018-01-01

    We assessed the feasibility of a data-driven imaging biomarker based on weakly supervised learning (DIB; an imaging biomarker derived from large-scale medical image data with deep learning technology) in mammography (DIB-MG). A total of 29,107 digital mammograms from five institutions (4,339 cancer cases and 24,768 normal cases) were included. After matching patients’ age, breast density, and equipment, 1,238 and 1,238 cases were chosen as validation and test sets, respectively, and the remai...

  19. Optical fiber imaging for high speed plasma motion diagnostics: Applied to low voltage circuit breakers

    International Nuclear Information System (INIS)

    McBride, J. W.; Balestrero, A.; Tribulato, G.; Ghezzi, L.; Cross, K. J.

    2010-01-01

    An integrated portable measurement system is described for the study of high speed and high temperature unsteady plasma flows such as those found in the vicinity of high current switching arcs. An array of optical fibers allows the formation of low spatial resolution images, with a maximum capture rate of 1x10 6 images per second (1 MHz), with 8 bit intensity resolution. Novel software techniques are reported to allow imaging of the arc; and to measure arc trajectories. Results are presented on high current (2 kA) discharge events in a model test fixture and on the application to a commercial low voltage circuit breaker.

  20. Acoustic biosensors.

    Science.gov (United States)

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  1. Quality control of structural MRI images applied using FreeSurfer - a hands-on workflow to rate motion artifacts

    Directory of Open Access Journals (Sweden)

    Lea Luise Backhausen

    2016-12-01

    Full Text Available In structural magnetic resonance imaging motion artifacts are common, especially when not scanning healthy young adults. It has been shown that motion affects the analysis with automated image-processing techniques (e.g. FreeSurfer. This can bias results. Several developmental and adult studies have found reduced volume and thickness of gray matter due to motion artifacts. Thus, quality control is necessary in order to ensure an acceptable level of quality and to define exclusion criteria of images (i.e. determine participants with most severe artifacts. However, information about the quality control workflow and image exclusion procedure is largely lacking in the current literature and the existing rating systems differ. Here we propose a stringent workflow of quality control steps during and after acquisition of T1-weighted images, which enables researchers dealing with populations that are typically affected by motion artifacts to enhance data quality and maximize sample sizes. As an underlying aim we established a thorough quality control rating system for T1-weighted images and applied it to the analysis of developmental clinical data using the automated processing pipeline FreeSurfer. This hands-on workflow and quality control rating system will aid researchers in minimizing motion artifacts in the final data set, and therefore enhance the quality of structural magnetic resonance imaging studies.

  2. Optimized lighting method of applying shaped-function signal for increasing the dynamic range of LED-multispectral imaging system

    Science.gov (United States)

    Yang, Xue; Hu, Yajia; Li, Gang; Lin, Ling

    2018-02-01

    This paper proposes an optimized lighting method of applying a shaped-function signal for increasing the dynamic range of light emitting diode (LED)-multispectral imaging system. The optimized lighting method is based on the linear response zone of the analog-to-digital conversion (ADC) and the spectral response of the camera. The auxiliary light at a higher sensitivity-camera area is introduced to increase the A/D quantization levels that are within the linear response zone of ADC and improve the signal-to-noise ratio. The active light is modulated by the shaped-function signal to improve the gray-scale resolution of the image. And the auxiliary light is modulated by the constant intensity signal, which is easy to acquire the images under the active light irradiation. The least square method is employed to precisely extract the desired images. One wavelength in multispectral imaging based on LED illumination was taken as an example. It has been proven by experiments that the gray-scale resolution and the accuracy of information of the images acquired by the proposed method were both significantly improved. The optimum method opens up avenues for the hyperspectral imaging of biological tissue.

  3. Criteria for applying imaging diagnosis and initial management for pediatric head trauma

    International Nuclear Information System (INIS)

    Shiomi, Naoto; Okada, Michiko; Echigo, Tadashi; Oka, Hideki; Hino, Akihiko

    2010-01-01

    It may be difficult to perform CT for pediatric head trauma because of body movement and radiation exposure. Imaging application criteria were established, in which patients diagnosed as less likely to have an intracranial lesion meeting the criteria were not indicated for imaging and subjected to course observation at home, and this policy was explained to the parents. When consent was obtained, patients were followed up at home, and we checked on the condition by making a phone call 4-8 hours after injury. The patients were 103 infants aged 15 years or younger brought to the emergency medical care center of our hospital between May and August 2008. Imaging was basically indicated for cases of traffic accidents, falls from a high level, those brought in by ambulance, referred cases, and cases with disturbance of consciousness, neurologically abnormal findings, vomiting on examination, and trauma requiring X-ray examination in addition to that for the head. However, apart from these cases, imaging was not required. Imaging was not necessary for 94% of infant cases. The parents were convinced by the explanation and selected course observation at home in 94% of cases for which imaging was judged as unnecessary. None of the patients required re-examination based on the conditions reported in phone calls to homes. Imaging diagnosis for pediatric head trauma is not always necessary, and its application should be decided on after consultation. When no imaging is performed, this should be fully explained at the initial treatment before selecting course observation at home. Checking on the child's condition by making a phone call several hours after injury is useful for both patients and physicians. (author)

  4. Fast and accurate denoising method applied to very high resolution optical remote sensing images

    Science.gov (United States)

    Masse, Antoine; Lefèvre, Sébastien; Binet, Renaud; Artigues, Stéphanie; Lassalle, Pierre; Blanchet, Gwendoline; Baillarin, Simon

    2017-10-01

    Restoration of Very High Resolution (VHR) optical Remote Sensing Image (RSI) is critical and leads to the problem of removing instrumental noise while keeping integrity of relevant information. Improving denoising in an image processing chain implies increasing image quality and improving performance of all following tasks operated by experts (photo-interpretation, cartography, etc.) or by algorithms (land cover mapping, change detection, 3D reconstruction, etc.). In a context of large industrial VHR image production, the selected denoising method should optimized accuracy and robustness with relevant information and saliency conservation, and rapidity due to the huge amount of data acquired and/or archived. Very recent research in image processing leads to a fast and accurate algorithm called Non Local Bayes (NLB) that we propose to adapt and optimize for VHR RSIs. This method is well suited for mass production thanks to its best trade-off between accuracy and computational complexity compared to other state-of-the-art methods. NLB is based on a simple principle: similar structures in an image have similar noise distribution and thus can be denoised with the same noise estimation. In this paper, we describe in details algorithm operations and performances, and analyze parameter sensibilities on various typical real areas observed in VHR RSIs.

  5. A study on the acoustical holography

    International Nuclear Information System (INIS)

    Shin, S.H.; Lee, J.H.; Jang, M.S.

    1979-01-01

    Theoretical and experimental investigations of acoustical holograms, and the optical reconstruction of their images are described. Acoustical holograms are constructed through the use of sound waves of 14 KHz-16 KHz frequency range. The virtual images and conjugate images are reconstructed using He-Ne gas laser(Wavelength 6,328A) light. The effect on the reconstructed images of the wavelength of the sound waves and of the scanning plane are discussed. Furthermore, the three dimensional information memory in acoustical holograms is discussed. (author)

  6. WE-EF-210-07: Development of a Minimally Invasive Photo Acoustic Imaging System for Early Prostate Cancer Detection

    Energy Technology Data Exchange (ETDEWEB)

    Sano, M; Yousefi, S; Xing, L [Stanford University School of Medicine, Stanford, CA (United States)

    2015-06-15

    Purpose: The objective of this work is to design, implement and characterize a catheter-based ultrasound/photoacoustic imaging probe for early-diagnosis of prostate cancer and to aid in image-guided radiation therapy. Methods: The need to image across 6–10cm of tissue to image the whole prostate gland limits the resolution achievable with a transrectal ultrasound approach. In contrast, the urethra bisects the prostate gland, providing a minimally invasive pathway for deploying a high resolution ultrasound transducer. Utilizing a high-frequency (20MHz) ultrasound/photoacoustic probe, high-resolution structural and molecular imaging of the prostate tissue is possible. A custom 3D printed probe containing a high-frequency single-element ultrasound transducer is utilized. The diameter of the probe is designed to fit inside a Foley catheter and the probe is rotated around the central axis to achieve a circular B-scan. A custom ultrasound amplifier and receiver was set up to trigger the ultrasound pulse transmission and record the reflected signal. The reconstructed images were compared to images generated by traditional 5 MHz ultrasound transducers. Results: The preliminary results using the high-frequency ultrasound probe show that it is possible to resolve finely detailed information in a prostate tissue phantom that was not achievable with previous low-frequency ultrasound systems. Preliminary ultrasound imaging was performed on tissue mimicking phantom and sensitivity and signal-to-noise ratio of the catheter was measured. Conclusion: In order to achieve non-invasive, high-resolution, structural and molecular imaging for early-diagnosis and image-guided radiation therapy of the prostate tissue, a transurethral catheter was designed. Structural/molecular imaging using ultrasound/photoacoustic of the prostate tissue will allow for localization of hyper vascularized areas for early-stage prostate cancer diagnosis.

  7. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  8. Building Acoustics

    Science.gov (United States)

    Cowan, James

    This chapter summarizes and explains key concepts of building acoustics. These issues include the behavior of sound waves in rooms, the most commonly used rating systems for sound and sound control in buildings, the most common noise sources found in buildings, practical noise control methods for these sources, and the specific topic of office acoustics. Common noise issues for multi-dwelling units can be derived from most of the sections of this chapter. Books can be and have been written on each of these topics, so the purpose of this chapter is to summarize this information and provide appropriate resources for further exploration of each topic.

  9. Treatment verification with megavoltage electronic portal imaging applied to the tomotherapy concept

    International Nuclear Information System (INIS)

    Hesse, B.-M.; Spies, L.; Groh, B.; Doll, J.; Haering, P.; Hoever, K. H.

    1997-01-01

    Purpose: A new treatment strategy called Tomotherapy, introduced by T. R. Mackie et al. in 1993, was designed to perform a dynamic conformal treatment technique in precision radiotherapy. This technique delivers sliced intensity-modulated radiation fields to achieve best tumor control while sparing neighbouring sensitive normal tissue and organs at risk. The beam continuously revolves around the patient similarly to a spiral-CT while the patient is moved through the bore of the gantry. As a first step towards the realization of such a concept with a linear accelerator (Siemens Mevatron Experimental) used in clinical routine, we focused on treatment setup and dose verification. In tomotherapy, an actual CT data set is needed for patient positioning and for the verification of the absorbed dose, also, the dose transmitted through the patient must be known. This makes possible both routine tomographic treatment setup verification and tomographic dose reconstruction of the actual delivered dose. Materials and Methods: All measurements were performed with a megavoltage electronic portal imaging device of Wellhoefer TM (BIS-710). The BIS-710 detector is based on a scintillation foil and contains a camera for 10-bit digital data output. The dimension of the detector plane is 512 x 512 pixels with a pixel size of 0.6 mm in each direction. The BIS-710 was developed especially for quantitative dose measuring, whereas most of the existing Portal Imaging Systems are used for image display only. To examine the properties of the BIS-710 concerning tomographical reconstruction with a therapeutic 6 MV X-ray beam, a tissue-equivalent Alderson head phantom was rotated stepwise across a stationary beam between the collimator and the detector plane. The influence of scattering can be estimated by comparing measurements which were taken with a homogeneous phantom which is invariant under rotation with a calculated exit dose distribution using a simple exponential law for the

  10. Image Fusion Applied to Satellite Imagery for the Improved Mapping and Monitoring of Coral Reefs: a Proposal

    Science.gov (United States)

    Gholoum, M.; Bruce, D.; Hazeam, S. Al

    2012-07-01

    A coral reef ecosystem, one of the most complex marine environmental systems on the planet, is defined as biologically diverse and immense. It plays an important role in maintaining a vast biological diversity for future generations and functions as an essential spawning, nursery, breeding and feeding ground for many kinds of marine species. In addition, coral reef ecosystems provide valuable benefits such as fisheries, ecological goods and services and recreational activities to many communities. However, this valuable resource is highly threatened by a number of environmental changes and anthropogenic impacts that can lead to reduced coral growth and production, mass coral mortality and loss of coral diversity. With the growth of these threats on coral reef ecosystems, there is a strong management need for mapping and monitoring of coral reef ecosystems. Remote sensing technology can be a valuable tool for mapping and monitoring of these ecosystems. However, the diversity and complexity of coral reef ecosystems, the resolution capabilities of satellite sensors and the low reflectivity of shallow water increases the difficulties to identify and classify its features. This paper reviews the methods used in mapping and monitoring coral reef ecosystems. In addition, this paper proposes improved methods for mapping and monitoring coral reef ecosystems based on image fusion techniques. This image fusion techniques will be applied to satellite images exhibiting high spatial and low to medium spectral resolution with images exhibiting low spatial and high spectral resolution. Furthermore, a new method will be developed to fuse hyperspectral imagery with multispectral imagery. The fused image will have a large number of spectral bands and it will have all pairs of corresponding spatial objects. This will potentially help to accurately classify the image data. Accuracy assessment use ground truth will be performed for the selected methods to determine the quality of the

  11. IMAGE FUSION APPLIED TO SATELLITE IMAGERY FOR THE IMPROVED MAPPING AND MONITORING OF CORAL REEFS: A PROPOSAL

    Directory of Open Access Journals (Sweden)

    M. Gholoum

    2012-07-01

    Full Text Available A coral reef ecosystem, one of the most complex marine environmental systems on the planet, is defined as biologically diverse and immense. It plays an important role in maintaining a vast biological diversity for future generations and functions as an essential spawning, nursery, breeding and feeding ground for many kinds of marine species. In addition, coral reef ecosystems provide valuable benefits such as fisheries, ecological goods and services and recreational activities to many communities. However, this valuable resource is highly threatened by a number of environmental changes and anthropogenic impacts that can lead to reduced coral growth and production, mass coral mortality and loss of coral diversity. With the growth of these threats on coral reef ecosystems, there is a strong management need for mapping and monitoring of coral reef ecosystems. Remote sensing technology can be a valuable tool for mapping and monitoring of these ecosystems. However, the diversity and complexity of coral reef ecosystems, the resolution capabilities of satellite sensors and the low reflectivity of shallow water increases the difficulties to identify and classify its features. This paper reviews the methods used in mapping and monitoring coral reef ecosystems. In addition, this paper proposes improved methods for mapping and monitoring coral reef ecosystems based on image fusion techniques. This image fusion techniques will be applied to satellite images exhibiting high spatial and low to medium spectral resolution with images exhibiting low spatial and high spectral resolution. Furthermore, a new method will be developed to fuse hyperspectral imagery with multispectral imagery. The fused image will have a large number of spectral bands and it will have all pairs of corresponding spatial objects. This will potentially help to accurately classify the image data. Accuracy assessment use ground truth will be performed for the selected methods to determine

  12. Applying Data-driven Imaging Biomarker in Mammography for Breast Cancer Screening: Preliminary Study.

    Science.gov (United States)

    Kim, Eun-Kyung; Kim, Hyo-Eun; Han, Kyunghwa; Kang, Bong Joo; Sohn, Yu-Mee; Woo, Ok Hee; Lee, Chan Wha

    2018-02-09

    We assessed the feasibility of a data-driven imaging biomarker based on weakly supervised learning (DIB; an imaging biomarker derived from large-scale medical image data with deep learning technology) in mammography (DIB-MG). A total of 29,107 digital mammograms from five institutions (4,339 cancer cases and 24,768 normal cases) were included. After matching patients' age, breast density, and equipment, 1,238 and 1,238 cases were chosen as validation and test sets, respectively, and the remainder were used for training. The core algorithm of DIB-MG is a deep convolutional neural network; a deep learning algorithm specialized for images. Each sample (case) is an exam composed of 4-view images (RCC, RMLO, LCC, and LMLO). For each case in a training set, the cancer probability inferred from DIB-MG is compared with the per-case ground-truth label. Then the model parameters in DIB-MG are updated based on the error between the prediction and the ground-truth. At the operating point (threshold) of 0.5, sensitivity was 75.6% and 76.1% when specificity was 90.2% and 88.5%, and AUC was 0.903 and 0.906 for the validation and test sets, respectively. This research showed the potential of DIB-MG as a screening tool for breast cancer.

  13. Applying a new mammographic imaging marker to predict breast cancer risk

    Science.gov (United States)

    Aghaei, Faranak; Danala, Gopichandh; Hollingsworth, Alan B.; Stoug, Rebecca G.; Pearce, Melanie; Liu, Hong; Zheng, Bin

    2018-02-01

    Identifying and developing new mammographic imaging markers to assist prediction of breast cancer risk has been attracting extensive research interest recently. Although mammographic density is considered an important breast cancer risk, its discriminatory power is lower for predicting short-term breast cancer risk, which is a prerequisite to establish a more effective personalized breast cancer screening paradigm. In this study, we presented a new interactive computer-aided detection (CAD) scheme to generate a new quantitative mammographic imaging marker based on the bilateral mammographic tissue density asymmetry to predict risk of cancer detection in the next subsequent mammography screening. An image database involving 1,397 women was retrospectively assembled and tested. Each woman had two digital mammography screenings namely, the "current" and "prior" screenings with a time interval from 365 to 600 days. All "prior" images were originally interpreted negative. In "current" screenings, these cases were divided into 3 groups, which include 402 positive, 643 negative, and 352 biopsy-proved benign cases, respectively. There is no significant difference of BIRADS based mammographic density ratings between 3 case groups (p cancer detection in the "current" screening. Study demonstrated that this new imaging marker had potential to yield significantly higher discriminatory power to predict short-term breast cancer risk.

  14. Stable And Oscillating Acoustic Levitation

    Science.gov (United States)

    Barmatz, Martin B.; Garrett, Steven L.

    1988-01-01

    Sample stability or instability determined by levitating frequency. Degree of oscillation of acoustically levitated object along axis of levitation chamber controlled by varying frequency of acoustic driver for axis above or below frequency of corresponding chamber resonance. Stabilization/oscillation technique applied in normal Earth gravity, or in absence of gravity to bring object quickly to rest at nominal levitation position or make object oscillate in desired range about that position.

  15. Personal computer (PC) based image processing applied to fluid mechanics research

    Science.gov (United States)

    Cho, Y.-C.; Mclachlan, B. G.

    1987-01-01

    A PC based image processing system was employed to determine the instantaneous velocity field of a two-dimensional unsteady flow. The flow was visualized using a suspension of seeding particles in water, and a laser sheet for illumination. With a finite time exposure, the particle motion was captured on a photograph as a pattern of streaks. The streak pattern was digitized and processsed using various imaging operations, including contrast manipulation, noise cleaning, filtering, statistical differencing, and thresholding. Information concerning the velocity was extracted from the enhanced image by measuring the length and orientation of the individual streaks. The fluid velocities deduced from the randomly distributed particle streaks were interpolated to obtain velocities at uniform grid points. For the interpolation a simple convolution technique with an adaptive Gaussian window was used. The results are compared with a numerical prediction by a Navier-Stokes commputation.

  16. Double-Stage Delay Multiply and Sum Beamforming Algorithm Applied to Ultrasound Medical Imaging.

    Science.gov (United States)

    Mozaffarzadeh, Moein; Sadeghi, Masume; Mahloojifar, Ali; Orooji, Mahdi

    2018-03-01

    In ultrasound (US) imaging, delay and sum (DAS) is the most common beamformer, but it leads to low-quality images. Delay multiply and sum (DMAS) was introduced to address this problem. However, the reconstructed images using DMAS still suffer from the level of side lobes and low noise suppression. Here, a novel beamforming algorithm is introduced based on expansion of the DMAS formula. We found that there is a DAS algebra inside the expansion, and we proposed use of the DMAS instead of the DAS algebra. The introduced method, namely double-stage DMAS (DS-DMAS), is evaluated numerically and experimentally. The quantitative results indicate that DS-DMAS results in an approximately 25% lower level of side lobes compared with DMAS. Moreover, the introduced method leads to 23%, 22% and 43% improvement in signal-to-noise ratio, full width at half-maximum and contrast ratio, respectively, compared with the DMAS beamformer. Copyright © 2018. Published by Elsevier Inc.

  17. Image Analysis Based on Soft Computing and Applied on Space Shuttle During the Liftoff Process

    Science.gov (United States)

    Dominquez, Jesus A.; Klinko, Steve J.

    2007-01-01

    Imaging techniques based on Soft Computing (SC) and developed at Kennedy Space Center (KSC) have been implemented on a variety of prototype applications related to the safety operation of the Space Shuttle during the liftoff process. These SC-based prototype applications include detection and tracking of moving Foreign Objects Debris (FOD) during the Space Shuttle liftoff, visual anomaly detection on slidewires used in the emergency egress system for the Space Shuttle at the laJlIlch pad, and visual detection of distant birds approaching the Space Shuttle launch pad. This SC-based image analysis capability developed at KSC was also used to analyze images acquired during the accident of the Space Shuttle Columbia and estimate the trajectory and velocity of the foam that caused the accident.

  18. Evaluation of LANDSAT-2 (ERTS) images applied to geologic structures and mineral resources of South America

    Science.gov (United States)

    Carter, W. D. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. Work with the Image 100 clearly demonstrates that radiance values of LANDSAT data can be used for correlation of geologic formations across international boundaries. The Totora Formation of the Corocoro Group of Tertiary age was traced from known outcrops near Tiahuanaco, Bolivia, along the south side of Lake Titicaca westward into Peru where the same rocks are considered to be Cretaceous in age. This inconsistency suggests: (1) that a review of this formation is needed by joint geological surveys of both countries to determine similarities, differences, and the true age; (2) that recognition of the extension of the copper-bearing Totora Formation of Bolivia into Peru may provide Peru with a new target for exploration. Equal radiance maps made by use of the Image 100 system show as many as eight different units within salar deposits (salt flats) of the Bolivian Altiplano. Standard film processed images show them as nearly uniform areas of white because of lack of dynamic range in film products. The Image 100 system, therefore, appears to be of great assistance in subdividing the salt flats on the basis of moisture distribution, surface roughness, and distribution of windblown materials. Field work is needed to determine these relationships to mineral composition and distribution. Images representing seasonal changes should also improve the accuracy of such maps. Radiance values of alteration zones related to the occurrence of porphyry copper ores were measured at the San Juan del Abra deposit of northern Chile using the Image 100 system. The extent to which these same values may be used to detect similar alteration zones in other areas has not yet been tested.

  19. Intelligent simulated annealing algorithm applied to the optimization of the main magnet for magnetic resonance imaging machine

    International Nuclear Information System (INIS)

    Sanchez Lopez, Hector

    2001-01-01

    This work describes an alternative algorithm of Simulated Annealing applied to the design of the main magnet for a Magnetic Resonance Imaging machine. The algorithm uses a probabilistic radial base neuronal network to classify the possible solutions, before the objective function evaluation. This procedure allows reducing up to 50% the number of iterations required by simulated annealing to achieve the global maximum, when compared with the SA algorithm. The algorithm was applied to design a 0.1050 Tesla four coil resistive magnet, which produces a magnetic field 2.13 times more uniform than the solution given by SA. (author)

  20. A quantitative performance evaluation of the EM algorithm applied to radiographic images

    International Nuclear Information System (INIS)

    Brailean, J.C.; Sullivan, B.J.; Giger, M.L.; Chen, C.T.

    1991-01-01

    In this paper, the authors quantitatively evaluate the performance of the Expectation Maximization (EM) algorithm as a restoration technique for radiographic images. The perceived signal-to-noise ratio (SNR), of simple radiographic patterns processed by the EM algorithm are calculated on the basis of a statistical decision theory model that includes both the observer's visual response function and a noise component internal to the eye-brain system. The relative SNR (ratio of the processed SNR to the original SNR) is calculated and used as a metric to quantitatively compare the effects of the EM algorithm to two popular image enhancement techniques: contrast enhancement (windowing) and unsharp mask filtering

  1. Clinical advances of SPECT rCBF and interventional imaging applied in the diagnosis of dementias

    International Nuclear Information System (INIS)

    Zhang Kaijun

    2002-01-01

    Brain perfusion SPECT is a functional and noninvasive neuroimaging technique that allow the investigation of physiological and physiopathologic events in the human brain, including cerebral perfusion and function. Interventional rCBF imaging can also evaluate cerebrovascular reserve. In clinically, rCBF imaging play an important role in the diagnosis and differential diagnosis of dementias, especially vascular and Alzheimer's dementia. If etiology of some types of dementias is determined so that it can be early diagnosed, treated and taken prevention; the partial patients with dementia can get recovery or remission

  2. A new automated assessment method for contrast–detail images by applying support vector machine and its robustness to nonlinear image processing

    International Nuclear Information System (INIS)

    Takei, Takaaki; Ikeda, Mitsuru; Imai, Kumiharu; Yamauchi-Kawaura, Chiyo; Kato, Katsuhiko; Isoda, Haruo

    2013-01-01

    The automated contrast–detail (C–D) analysis methods developed so-far cannot be expected to work well on images processed with nonlinear methods, such as noise reduction methods. Therefore, we have devised a new automated C–D analysis method by applying support vector machine (SVM), and tested for its robustness to nonlinear image processing. We acquired the CDRAD (a commercially available C–D test object) images at a tube voltage of 120 kV and a milliampere-second product (mAs) of 0.5–5.0. A partial diffusion equation based technique was used as noise reduction method. Three radiologists and three university students participated in the observer performance study. The training data for our SVM method was the classification data scored by the one radiologist for the CDRAD images acquired at 1.6 and 3.2 mAs and their noise-reduced images. We also compared the performance of our SVM method with the CDRAD Analyser algorithm. The mean C–D diagrams (that is a plot of the mean of the smallest visible hole diameter vs. hole depth) obtained from our devised SVM method agreed well with the ones averaged across the six human observers for both original and noise-reduced CDRAD images, whereas the mean C–D diagrams from the CDRAD Analyser algorithm disagreed with the ones from the human observers for both original and noise-reduced CDRAD images. In conclusion, our proposed SVM method for C–D analysis will work well for the images processed with the non-linear noise reduction method as well as for the original radiographic images.

  3. A new automated assessment method for contrast-detail images by applying support vector machine and its robustness to nonlinear image processing.

    Science.gov (United States)

    Takei, Takaaki; Ikeda, Mitsuru; Imai, Kuniharu; Yamauchi-Kawaura, Chiyo; Kato, Katsuhiko; Isoda, Haruo

    2013-09-01

    The automated contrast-detail (C-D) analysis methods developed so-far cannot be expected to work well on images processed with nonlinear methods, such as noise reduction methods. Therefore, we have devised a new automated C-D analysis method by applying support vector machine (SVM), and tested for its robustness to nonlinear image processing. We acquired the CDRAD (a commercially available C-D test object) images at a tube voltage of 120 kV and a milliampere-second product (mAs) of 0.5-5.0. A partial diffusion equation based technique was used as noise reduction method. Three radiologists and three university students participated in the observer performance study. The training data for our SVM method was the classification data scored by the one radiologist for the CDRAD images acquired at 1.6 and 3.2 mAs and their noise-reduced images. We also compared the performance of our SVM method with the CDRAD Analyser algorithm. The mean C-D diagrams (that is a plot of the mean of the smallest visible hole diameter vs. hole depth) obtained from our devised SVM method agreed well with the ones averaged across the six human observers for both original and noise-reduced CDRAD images, whereas the mean C-D diagrams from the CDRAD Analyser algorithm disagreed with the ones from the human observers for both original and noise-reduced CDRAD images. In conclusion, our proposed SVM method for C-D analysis will work well for the images processed with the non-linear noise reduction method as well as for the original radiographic images.

  4. A pilot study of the characterization of hepatic tissue strain in children with cystic-fibrosis-associated liver disease (CFLD) by acoustic radiation force impulse imaging

    International Nuclear Information System (INIS)

    Behrens, Christopher B.; Langholz, Juliane H.; Eiler, Jessika; Jenewein, Raphael; Fuchs, Konstantin; Alzen, Gerhard F.P.; Naehrlich, Lutz; Harth, Sebastian; Krombach, Gabriele A.

    2013-01-01

    Progressive fibrotic alterations of liver tissue represent a major complication in children with cystic fibrosis. Correct assessment of cystic-fibrosis-associated liver disease (CFLD) in clinical routine is a challenging issue. Sonographic elastography based on acoustic radiation force impulse imaging (ARFI) is a new noninvasive approach for quantitatively assessing in vivo elasticity of biological tissues in many organs. To characterize ARFI elastography as a diagnostic tool to assess alteration of liver tissue elasticity related to cystic fibrosis in children. ARFI elastography and B-mode US imaging were performed in 36 children with cystic fibrosis. The children's clinical history and laboratory parameters were documented. According to the findings on conventional US, children were assigned to distinct groups indicating severity of hepatic tissue alterations. The relationship between US findings and respective elastography values was assessed. Additionally, differences between ARFI elastography values of each US group were statistically tested. Children with sonomorphologic characteristics of fibrotic tissue remodeling presented significantly increased values for tissue elasticity. Children with normal B-mode US or discrete signs of hepatic tissue alterations showed a tendency toward increased tissue stiffness indicating early tissue remodeling. Assessment of children with CFLD by means of ARFI elastography yields adequate results when compared to conventional US. For detection of early stages of liver disease with mild fibrotic reactions of hepatic tissue, ARFI elastography might offer diagnostic advantages over conventional US. Thus, liver stiffness measured by means of elastography might represent a valuable biological parameter for evaluation and follow-up of CFLD. (orig.)

  5. A pilot study of the characterization of hepatic tissue strain in children with cystic-fibrosis-associated liver disease (CFLD) by acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Christopher B.; Langholz, Juliane H.; Eiler, Jessika; Jenewein, Raphael; Fuchs, Konstantin; Alzen, Gerhard F.P. [University Hospital Giessen, Department of Pediatric Radiology, Giessen (Germany); Naehrlich, Lutz [University Hospital Giessen, Department of Pediatrics, Giessen (Germany); Harth, Sebastian; Krombach, Gabriele A. [University Hospital Giessen, Department of Radiology, Giessen (Germany)

    2013-03-15

    Progressive fibrotic alterations of liver tissue represent a major complication in children with cystic fibrosis. Correct assessment of cystic-fibrosis-associated liver disease (CFLD) in clinical routine is a challenging issue. Sonographic elastography based on acoustic radiation force impulse imaging (ARFI) is a new noninvasive approach for quantitatively assessing in vivo elasticity of biological tissues in many organs. To characterize ARFI elastography as a diagnostic tool to assess alteration of liver tissue elasticity related to cystic fibrosis in children. ARFI elastography and B-mode US imaging were performed in 36 children with cystic fibrosis. The children's clinical history and laboratory parameters were documented. According to the findings on conventional US, children were assigned to distinct groups indicating severity of hepatic tissue alterations. The relationship between US findings and respective elastography values was assessed. Additionally, differences between ARFI elastography values of each US group were statistically tested. Children with sonomorphologic characteristics of fibrotic tissue remodeling presented significantly increased values for tissue elasticity. Children with normal B-mode US or discrete signs of hepatic tissue alterations showed a tendency toward increased tissue stiffness indicating early tissue remodeling. Assessment of children with CFLD by means of ARFI elastography yields adequate results when compared to conventional US. For detection of early stages of liver disease with mild fibrotic reactions of hepatic tissue, ARFI elastography might offer diagnostic advantages over conventional US. Thus, liver stiffness measured by means of elastography might represent a valuable biological parameter for evaluation and follow-up of CFLD. (orig.)

  6. On Architectural Acoustics Design using Computer Simulation

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    The acoustical quality of a given building, or space within the building, is highly dependent on the architectural design. Architectural acoustics design has in the past been based on simple design rules. However, with a growing complexity in the architectural acoustic and the emergence of potent...... room acoustic simulation programs it is now possible to subjectively analyze and evaluate acoustic properties prior to the actual construction of a facility. With the right tools applied, the acoustic design can become an integrated part of the architectural design process. The aim of the present paper...... this information is discussed. The conclusion of the paper is that the application of acoustical simulation programs is most beneficial in the last of three phases but that an application of the program to the two first phases would be preferable and possible with an improvement of the interface of the program....

  7. A sampler of useful computational tools for applied geometry, computer graphics, and image processing foundations for computer graphics, vision, and image processing

    CERN Document Server

    Cohen-Or, Daniel; Ju, Tao; Mitra, Niloy J; Shamir, Ariel; Sorkine-Hornung, Olga; Zhang, Hao (Richard)

    2015-01-01

    A Sampler of Useful Computational Tools for Applied Geometry, Computer Graphics, and Image Processing shows how to use a collection of mathematical techniques to solve important problems in applied mathematics and computer science areas. The book discusses fundamental tools in analytical geometry and linear algebra. It covers a wide range of topics, from matrix decomposition to curvature analysis and principal component analysis to dimensionality reduction.Written by a team of highly respected professors, the book can be used in a one-semester, intermediate-level course in computer science. It

  8. An Adaptive Spectrally Weighted Structure Tensor Applied to Tensor Anisotropic Nonlinear Diffusion for Hyperspectral Images

    Science.gov (United States)

    Marin Quintero, Maider J.

    2013-01-01

    The structure tensor for vector valued images is most often defined as the average of the scalar structure tensors in each band. The problem with this definition is the assumption that all bands provide the same amount of edge information giving them the same weights. As a result non-edge pixels can be reinforced and edges can be weakened…

  9. Educating Future Engineers and the Image of Technology : Applying the Philosophy of Technology to Engineering Education

    NARCIS (Netherlands)

    Ghaemi Nia, M.M.

    2017-01-01

    This thesis deals with the matter of making reforms in engineering education, and it highlights the significance of delivering a more comprehensive image of technology and its different aspects in the course of training students about technology and engineering. The innovative contribution of the

  10. Multimodality cranial image fusion using external markers applied via a vacuum mouthpiece and a case report

    International Nuclear Information System (INIS)

    Sweeney, R.A.; Seydl, K.; Lukas, P.; Bale, R.J.; Trieb, T.; Moncayo, R.; Donnemiller, E.; Eisner, W.; Burtscher, J.; Stockhammer, G.

    2003-01-01

    Purpose: To present a simple and precise method of combining functional information of cranial SPECT and PET images with CT and MRI, in any combination. Material and Methods: Imaging is performed with a hockey mask-like reference frame with image modality-specific markers in precisely defined positions. This frame is reproducibly connected to the VBH vacuum mouthpiece, granting objectively identical repositioning of the frame with respect to the cranium. Using these markers, the desired 3-D imaging modalities can then be manually or automatically registered. This information can be used for diagnosis, treatment planning, and evaluation of follow-up, while the same vacuum mouthpiece allows precisely reproducible stereotactic head fixation during radiotherapy. Results: 244 CT and MR data sets of 49 patients were registered to a root square mean error (RSME) of 0.9 mm (mean). 64 SPECT-CT fusions on 18 of these patients gave an RMSE of 1.4 mm, and 40 PET-CT data sets of eight patients were registered to 1.3 mm. An example of the method is given by means of a case report of a 52-year-old patient with bilateral optic nerve meningioma. Conclusion: This technique is a simple, objective and accurate registration tool to combine diagnosis, treatment planning, treatment, and follow-up, all via an individualized vacuum mouthpiece. Especially for low-resolution PET and even more so for some very diffuse SPECT data sets, activity can now be accurately correlated to anatomic structures. (orig.)

  11. Lessons from Coronagraphic Imaging with HST that may apply to JWST

    Science.gov (United States)

    Grady, C. A.; Hines, Dean C.; Schneider, Glenn; McElwain, Michael W.

    2017-06-01

    One of the major capabilities offered by JWST is coronagraphic imaging from space, covering the near through mid-IR and optimized for study of planet formation and the evolution of planetary systems. Planning for JWST has resulted in expectations for instrument performance, observation strategies and data reduction approaches. HST with 20 years of coronagraphic imaging offers some experience which may be useful to those planning for JWST. 1) Real astronomical sources do not necessarily conform to expectations. Debris disks may be accompanied by more distant material, and some systems may be conspicuous in scattered light when offering only modest IR excesses. Proto-planetary disks are not constantly illuminated, and thus a single epoch observation of the source may not be sufficient to reveal everything about it. 2) The early expectation with NICMOS was that shallow, 2-roll observations would reveal a wealth of debris disks imaged in scattered light, and that only a limited set of PSF observations would be required. Instead, building up a library of spatially resolved disks in scattered light has proven to require alternate observing strategies, is still on-going, and has taken far longer than expected. 3) A wealth of coronagraphic options with an instrument may not be scientifically informative, unless there is a similar time investment in acquisition of calibration data in support of the science observations. 4) Finally, no one anticipated what can be gleaned from coronagraphic imaging. We should expect similar, unexpected, and ultimately revolutionary discoveries with JWST.

  12. An improved minimum variance beamforming applied to plane-wave imaging in medical ultrasound

    DEFF Research Database (Denmark)

    Deylami, Ali Mohades; Asl, Babak Mohammadzadeh; Jensen, Jørgen Arendt

    2016-01-01

    Minimum variance beamformer (MVB) is an adaptive beamformer which provides images with higher resolution and contrast in comparison with non-adaptive beamformers like delay and sum (DAS). It finds weight vector of beamformer by minimizing output power while keeping the desired signal unchanged. We...

  13. Influence of Images on the Evaluation of Jams Using Conjoint Analysis Combined with Check-All-That-Apply (CATA) Questions.

    Science.gov (United States)

    Miraballes, Marcelo; Gámbaro, Adriana

    2018-01-01

    A study of the influence of the use of images in a conjoint analysis combined with check-all-that apply (CATA) questions on jams was carried out. The relative importance of flavor and the information presented in the label in the willingness to purchase and the perception of how healthy the product is has been evaluated. Sixty consumers evaluated the stimuli presented only in text format (session 1), and another group of 60 consumers did so by receiving the stimuli in text format along with an image of the product (session 2). In addition, for each stimulus, consumers answered a CATA question consisting of 20 terms related to their involvement with the product. The perception of healthy increased when the texts were accompanied with images and also increased when the text included information. Willingness to purchase was only influenced by the flavor of the jams. The presence of images did not influence the CATA question's choice of terms, which were influenced by the information presented in the text. The use of a check-all-that-apply question in concepts provided an interesting possibility when they were combined with the results from the conjoint analysis, improving the comprehension of consumers' perception. Using CATA questions as an alternative way of evaluating consumer involvement seems to be beneficial and should be evaluated much further. © 2017 Institute of Food Technologists®.

  14. PVT Degradation Studies: Acoustic Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Dib, Gerges [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smith, Philip J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-04-01

    Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. This document reports on a study of acoustic techniques to determine whether they can provide a diagnostic for the fogging of PVT. Different ultrasound techniques were employed for detecting the level of internal fogging in PVT, including wave velocity measurements, attenuation, nonlinear acoustics, and acoustic microscopy. The results indicate that there are linear relations between the wave velocity and wave attenuation with the level of internal fogging. The effects of fogging on ultrasound wave attenuation is further verified by acoustic microscopy imaging, where regions with fog in the specimen demonstration higher levels of attenuation compared to clear regions. Results from the nonlinear ultrasound measurements were inconclusive due to high sensitivities to transducer coupling and fixture variabilities.

  15. Acoustic Characterization of Mesoscale Objects

    Energy Technology Data Exchange (ETDEWEB)

    Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T

    2007-03-13

    This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.

  16. Applying of the array transducers' technology for surface acoustic waves materials characterization in the transient regime; Application de la technologie multi-elements a la caracterisation des materiaux par ondes acoustiques de surface en regime impulsionnel

    Energy Technology Data Exchange (ETDEWEB)

    Frenet, D

    2000-07-01

    In this document we present a theoretical and experimental study which has been led to design a surface acoustic wave device for local characterisation (relatively to the wavelength) of isotropic or anisotropic materials. The device is based on a phased-array transducer of conical shape we have specifically designed for this purpose. It operates in the impulsive mode, in the frequency range of 1-5 MHz. In order to deduce mechanical properties of the material, it is possible to measure the surface wave characteristics (velocity, attenuation,...). Different methods for measuring the wave velocity have been developed taking advantage of from the phased-array technology. The originality of theses methods relies on the fact that the measures are performed without moving the transducer. Consequently, the device requires no additional mechanical system and it is quite compact. In addition, this shortens the characterisation process duration comparatively to the usually available methods (e. g. the V(z) technique). In the theoretical section of this study, a versatile model allowing to simulate in the time harmonic regime as well as in the transient regime, the transmitted field, the field reflected on isotropic or anisotropic planar samples and the output voltage for transducers of arbitrary shapes has been developed. The model has been applied to the phased-array conical transducer as well as to more classical transducers such as planar (rectangular) or focusing (spherically or cylindrically shaped) transducers. It predicts not only the geometrical contributions of the reflected field and signal but also the leaky contributions related to the surface acoustic waves. (author)

  17. An automatic image-based modelling method applied to forensic infography.

    Directory of Open Access Journals (Sweden)

    Sandra Zancajo-Blazquez

    Full Text Available This paper presents a new method based on 3D reconstruction from images that demonstrates the utility and integration of close-range photogrammetry and computer vision as an efficient alternative to modelling complex objects and scenarios of forensic infography. The results obtained confirm the validity of the method compared to other existing alternatives as it guarantees the following: (i flexibility, permitting work with any type of camera (calibrated and non-calibrated, smartphone or tablet and image (visible, infrared, thermal, etc.; (ii automation, allowing the reconstruction of three-dimensional scenarios in the absence of manual intervention, and (iii high quality results, sometimes providing higher resolution than modern laser scanning systems. As a result, each ocular inspection of a crime scene with any camera performed by the scientific police can be transformed into a scaled 3d model.

  18. Shanoir: Applying the Software as a Service Distribution Model to Manage Brain Imaging Research Repositories

    Directory of Open Access Journals (Sweden)

    Christian Barillot

    2016-12-01

    Full Text Available Two of the major concerns of researchers and clinicians performing neuroimaging experiments are managing the huge quantity and diversity of data and the ability to compare their experiments and the programs they develop with those of their peers. In this context, we introduce Shanoir, which uses a type of cloud computing known as software as a service (SaaS to manage neuroimaging data used in the clinical neurosciences. Thanks to a formal model of medical imaging data (an ontology, Shanoir provides an open source neuroinformatics environment designed to structure, manage, archive, visualize and share neuroimaging data with an emphasis on managing multi-institutional, collaborative research projects. This article covers how images are accessed through the Shanoir Data Management System and describes the data repositories that are hosted and managed by the Shanoir environment in different contexts.

  19. Image processing techniques applied to the detection of optic disk: a comparison

    Science.gov (United States)

    Kumari, Vijaya V.; Narayanan, Suriya N.

    2010-02-01

    In retinal image analysis, the detection of optic disk is of paramount importance. It facilitates the tracking of various anatomical features and also in the extraction of exudates, drusens etc., present in the retina of human eye. The health of retina crumbles with age in some people during the presence of exudates causing Diabetic Retinopathy. The existence of exudates increases the risk for age related macular Degeneration (AMRD) and it is the leading cause for blindness in people above the age of 50.A prompt diagnosis when the disease is at the early stage can help to prevent irreversible damages to the diabetic eye. Screening to detect diabetic retinopathy helps to prevent the visual loss. The optic disk detection is the rudimentary requirement for the screening. In this paper few methods for optic disk detection were compared which uses both the properties of optic disk and model based approaches. They are uniquely used to give accurate results in the retinal images.

  20. Technical Note: Harmonic analysis applied to MR image distortion fields specific to arbitrarily shaped volumes.

    Science.gov (United States)

    Stanescu, T; Jaffray, D

    2018-05-25

    Magnetic resonance imaging is expected to play a more important role in radiation therapy given the recent developments in MR-guided technologies. MR images need to consistently show high spatial accuracy to facilitate RT specific tasks such as treatment planning and in-room guidance. The present study investigates a new harmonic analysis method for the characterization of complex 3D fields derived from MR images affected by system-related distortions. An interior Dirichlet problem based on solving the Laplace equation with boundary conditions (BCs) was formulated for the case of a 3D distortion field. The second-order boundary value problem (BVP) was solved using a finite elements method (FEM) for several quadratic geometries - i.e., sphere, cylinder, cuboid, D-shaped, and ellipsoid. To stress-test the method and generalize it, the BVP was also solved for more complex surfaces such as a Reuleaux 9-gon and the MR imaging volume of a scanner featuring a high degree of surface irregularities. The BCs were formatted from reference experimental data collected with a linearity phantom featuring a volumetric grid structure. The method was validated by comparing the harmonic analysis results with the corresponding experimental reference fields. The harmonic fields were found to be in good agreement with the baseline experimental data for all geometries investigated. In the case of quadratic domains, the percentage of sampling points with residual values larger than 1 mm were 0.5% and 0.2% for the axial components and vector magnitude, respectively. For the general case of a domain defined by the available MR imaging field of view, the reference data showed a peak distortion of about 12 mm and 79% of the sampling points carried a distortion magnitude larger than 1 mm (tolerance intrinsic to the experimental data). The upper limits of the residual values after comparison with the harmonic fields showed max and mean of 1.4 mm and 0.25 mm, respectively, with only 1.5% of

  1. Image analysis to measure sorting and stratification applied to sand-gravel experiments

    OpenAIRE

    Orrú, C.

    2016-01-01

    The main objective of this project is to develop new measuring techniques for providing detailed data on sediment sorting suitable for sand-gravel laboratory experiments. Such data will be of aid in obtaining new insights on sorting mechanisms and improving prediction capabilities of morphodynamic models. Two measuring techniques have been developed. The first technique is aimed at measuring the size stratification of a sand-gravel deposit through combining image analysis and a sediment remov...

  2. Medical Image Processing Server applied to Quality Control of Nuclear Medicine

    International Nuclear Information System (INIS)

    Vergara, C.; Graffigna, J.P.; Holleywell, P.; Marino, E.; Omati, S.

    2016-01-01

    This paper is framed within the area of medical image processing and aims to present the process of installation, configuration and implementation of a processing server of medical images (MIPS) in the Fundación Escuela de Medicina Nuclear located in Mendoza, Argentina (FUESMEN). It has been developed in the Gabinete de Tecnologia Médica (GA.TE.ME), Facultad de Ingeniería-Universidad Nacional de San Juan. MIPS is a software that using the DICOM standard, can receive medical imaging studies of different modalities or viewing stations, then it executes algorithms and finally returns the results to other devices. To achieve the objectives previously mentioned, preliminary tests were conducted in the laboratory. More over, tools were remotely installed in clinical enviroment. The appropiate protocols for setting up and using them in different services were established once defined those suitable algorithms. Finally, it’s important to focus on the implementation and training that is provided in FUESMEN, using nuclear medicine quality control processes. Results on implementation are exposed in this work. (paper)

  3. Applying protein-based amide proton transfer MR imaging to distinguish solitary brain metastases from glioblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hao; Zou, Tianyu; Wang, Xianlong; Du, Yongxing; Jiang, Chunxiu; Ma, Ling; Zhu, Jianbin; He, Wen; Rui, Qihong; Wen, Zhibo [Zhujiang Hospital, Southern Medical University, Department of Radiology, Guangzhou, Guangdong (China); Lou, Huiling [The First People' Hospital of Guangzhou, Department of Geriatrics, Guangzhou, Guangdong (China); Jiang, Shanshan [Zhujiang Hospital, Southern Medical University, Department of Radiology, Guangzhou, Guangdong (China); Johns Hopkins University School of Medicine, Division of MR Research, Department of Radiology, Baltimore, MD (United States); Huang, Zhongqing [Shantou University Medical College, Department of Medical Image Center, Yuebei People' s Hospital, Shantou, Guangdong (China); Zhou, Jianyuan [Johns Hopkins University School of Medicine, Division of MR Research, Department of Radiology, Baltimore, MD (United States)

    2017-11-15

    To determine the utility of amide proton transfer-weighted (APTw) MR imaging in distinguishing solitary brain metastases (SBMs) from glioblastomas (GBMs). Forty-five patients with SBMs and 43 patients with GBMs underwent conventional and APT-weighted sequences before clinical intervention. The APTw parameters and relative APTw (rAPTw) parameters in the tumour core and the peritumoral brain zone (PBZ) were obtained and compared between SBMs and GBMs. The receiver-operating characteristic (ROC) curve was used to assess the best parameter for distinguishing between the two groups. The APTw{sub max}, APTw{sub min}, APTw{sub mean}, rAPTw{sub max}, rAPTw{sub min} or rAPTw{sub mean} values in the tumour core were not significantly different between the SBM and GBM groups (P = 0.141, 0.361, 0.221, 0.305, 0.578 and 0.448, respectively). However, the APTw{sub max}, APTw{sub min}, APTw{sub mean}, rAPTw{sub max}, rAPTw{sub min} or rAPTw{sub mean} values in the PBZ were significantly lower in the SBM group than in the GBM group (P < 0.001). The APTw{sub min} values had the highest area under the ROC curve 0.905 and accuracy 85.2% in discriminating between the two neoplasms. As a noninvasive imaging method, APT-weighted MR imaging can be used to distinguish SBMs from GBMs. (orig.)

  4. Medical Image Processing Server applied to Quality Control of Nuclear Medicine.

    Science.gov (United States)

    Vergara, C.; Graffigna, J. P.; Marino, E.; Omati, S.; Holleywell, P.

    2016-04-01

    This paper is framed within the area of medical image processing and aims to present the process of installation, configuration and implementation of a processing server of medical images (MIPS) in the Fundación Escuela de Medicina Nuclear located in Mendoza, Argentina (FUESMEN). It has been developed in the Gabinete de Tecnologia Médica (GA.TE.ME), Facultad de Ingeniería-Universidad Nacional de San Juan. MIPS is a software that using the DICOM standard, can receive medical imaging studies of different modalities or viewing stations, then it executes algorithms and finally returns the results to other devices. To achieve the objectives previously mentioned, preliminary tests were conducted in the laboratory. More over, tools were remotely installed in clinical enviroment. The appropiate protocols for setting up and using them in different services were established once defined those suitable algorithms. Finally, it’s important to focus on the implementation and training that is provided in FUESMEN, using nuclear medicine quality control processes. Results on implementation are exposed in this work.

  5. Applying x-ray digital imaging to the verification of cadmium in fuel-storage components

    International Nuclear Information System (INIS)

    Dabbs, R.D.; Cook, D.H.

    1997-01-01

    The High Flux Isotope Reactor utilizes large underwater fuel-storage arrays to stage irradiated fuel before it is shipped from the facility. Cadmium is required as a thermal neutron absorber in these fuel-storage arrays to produce an acceptable margin of nuclear subcriticality during both normal and off-normal operating conditions. Due to incomplete documentation from the time of their fabrication, the presence of cadmium within two stainless-steel parts of fuel-storage arrays must be experimentally verified before they are reused in new fuel-storage arrays. A cadmium-verification program has been developed in association with the Waste Examination and Assay Facility located at the Oak Ridge national Laboratory to nondestructively examine these older shroud assemblies. The program includes the following elements (1) x-ray analog imaging, (2) x-ray digital imaging, (3) prompt-gamma-ray spectroscopy measurements, and (4) neutron-transmission measurements. X-ray digital imaging utilizes an analog-to-digital convertor to record attenuated x-ray intensities observed on a fluorescent detector by a video camera. These x-ray intensities are utilized in expressions for cadmium thickness based upon x-ray attenuation theory

  6. Optimal processing for gel electrophoresis images: Applying Monte Carlo Tree Search in GelApp.

    Science.gov (United States)

    Nguyen, Phi-Vu; Ghezal, Ali; Hsueh, Ya-Chih; Boudier, Thomas; Gan, Samuel Ken-En; Lee, Hwee Kuan

    2016-08-01

    In biomedical research, gel band size estimation in electrophoresis analysis is a routine process. To facilitate and automate this process, numerous software have been released, notably the GelApp mobile app. However, the band detection accuracy is limited due to a band detection algorithm that cannot adapt to the variations in input images. To address this, we used the Monte Carlo Tree Search with Upper Confidence Bound (MCTS-UCB) method to efficiently search for optimal image processing pipelines for the band detection task, thereby improving the segmentation algorithm. Incorporating this into GelApp, we report a significant enhancement of gel band detection accuracy by 55.9 ± 2.0% for protein polyacrylamide gels, and 35.9 ± 2.5% for DNA SYBR green agarose gels. This implementation is a proof-of-concept in demonstrating MCTS-UCB as a strategy to optimize general image segmentation. The improved version of GelApp-GelApp 2.0-is freely available on both Google Play Store (for Android platform), and Apple App Store (for iOS platform). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Holograms for acoustics.

    Science.gov (United States)

    Melde, Kai; Mark, Andrew G; Qiu, Tian; Fischer, Peer

    2016-09-22

    Holographic techniques are fundamental to applications such as volumetric displays, high-density data storage and optical tweezers that require spatial control of intricate optical or acoustic fields within a three-dimensional volume. The basis of holography is spatial storage of the phase and/or amplitude profile of the desired wavefront in a manner that allows that wavefront to be reconstructed by interference when the hologram is illuminated with a suitable coherent source. Modern computer-generated holography skips the process of recording a hologram from a physical scene, and instead calculates the required phase profile before rendering it for reconstruction. In ultrasound applications, the phase profile is typically generated by discrete and independently driven ultrasound sources; however, these can only be used in small numbers, which limits the complexity or degrees of freedom that can be attained in the wavefront. Here we introduce monolithic acoustic holograms, which can reconstruct diffraction-limited acoustic pressure fields and thus arbitrary ultrasound beams. We use rapid fabrication to craft the holograms and achieve reconstruction degrees of freedom two orders of magnitude higher than commercial phased array sources. The technique is inexpensive, appropriate for both transmission and reflection elements, and scales well to higher information content, larger aperture size and higher power. The complex three-dimensional pressure and phase distributions produced by these acoustic holograms allow us to demonstrate new approaches to controlled ultrasonic manipulation of solids in water, and of liquids and solids in air. We expect that acoustic holograms will enable new capabilities in beam-steering and the contactless transfer of power, improve medical imaging, and drive new applications of ultrasound.

  8. Error analysis by means of acoustic holography

    International Nuclear Information System (INIS)

    Kutzner, J.; Wuestenberg, H.

    1976-01-01

    The possilbilities to use the acoustical holography in nondestructive testing are discussed. Although compared to optical holography the image quality of acoustical holography is reduced this technique can give important informations about the shape of defects. Especially in nondestructive testing of thick walled components no alternative exists until now. (orig.) [de

  9. New system applying image processor to automatically separate cation exchange resin and anion exchange resin for condensate demineralizer

    International Nuclear Information System (INIS)

    Adachi, Tsuneyasu; Nagao, Nobuaki; Yoshimori, Yasuhide; Inoue, Takashi; Yoda, Shuji

    2014-01-01

    In PWR plant, condensate demineralizer is equipped to remove corrosive ion in condensate water. Mixed bed packing cation exchange resin (CER) and anion exchange resin (AER) is generally applied, and these are regenerated after separation to each layer periodically. Since the AER particle is slightly lighter than the CER particle, the AER layer is brought up onto the CER layer by feeding water upward from the bottom of column (backwashing). The separation performance is affected by flow rate and temperature of water for backwashing, so normally operators set the proper condition parameters regarding separation manually every time for regeneration. The authors have developed the new separation system applying CCD camera and image processor. The system is comprised of CCD camera, LED lamp, image processor, controller, flow control valves and background color panel. Blue color of the panel, which is corresponding to the complementary color against both ivory color of AER and brown color of CER, is key to secure the system precision. At first the color image of the CER via the CCD camera is digitized and memorized by the image processor. The color of CER in the field of vision of the camera is scanned by the image processor, and the position where the maximum difference of digitized color index is indicated is judged as the interface. The detected interface is able to make the accordance with the set point by adjusting the flow rate of backwashing. By adopting the blue background panel, it is also possible to draw the AER out of the column since detecting the interface of the CER clearly. The system has provided the reduction of instability factor concerning separation of resin during regeneration process. The system has been adopted in two PWR plants in Japan, it has been demonstrating its stable and precise performance. (author)

  10. Non-invasive imaging methods applied to neo- and paleo-ontological cephalopod research

    Science.gov (United States)

    Hoffmann, R.; Schultz, J. A.; Schellhorn, R.; Rybacki, E.; Keupp, H.; Gerden, S. R.; Lemanis, R.; Zachow, S.

    2014-05-01

    Several non-invasive methods are common practice in natural sciences today. Here we present how they can be applied and contribute to current topics in cephalopod (paleo-) biology. Different methods will be compared in terms of time necessary to acquire the data, amount of data, accuracy/resolution, minimum/maximum size of objects that can be studied, the degree of post-processing needed and availability. The main application of the methods is seen in morphometry and volumetry of cephalopod shells. In particular we present a method for precise buoyancy calculation. Therefore, cephalopod shells were scanned together with different reference bodies, an approach developed in medical sciences. It is necessary to know the volume of the reference bodies, which should have similar absorption properties like the object of interest. Exact volumes can be obtained from surface scanning. Depending on the dimensions of the study object different computed tomography techniques were applied.

  11. Applying NASA Imaging Radar Datasets to Investigate the Geomorphology of the Amazon's Planalto

    Science.gov (United States)

    McDonald, K. C.; Campbell, K.; Islam, R.; Alexander, P. M.; Cracraft, J.

    2016-12-01

    The Amazon basin is a biodiversity rich biome and plays a significant role into shaping Earth's climate, ocean and atmospheric gases. Understanding the history of the formation of this basin is essential to our understanding of the region's biodiversity and its response to climate change. During March 2013, the NASA/JPL L-band polarimetric airborne imaging radar, UAVSAR, conducted airborne studies over regions of South America including portions of the western Amazon basin. We utilize UAVSAR imagery acquired during that time over the Planalto, in the Madre de Dios region of southeastern Peru in an assessment of the underlying geomorphology, its relationship to the current distribution of vegetation, and its relationship to geologic processes through deep time. We employ UAVSAR data collections to assess the utility of these high quality imaging radar data for use in identifying geomorphologic features and vegetation communities within the context of improving the understanding of evolutionary processes, and their utility in aiding interpretation of datasets from Earth-orbiting satellites to support a basin-wide characterization across the Amazon. We derive maps of landcover and river branching structure from UAVSAR imagery. We compare these maps to those derived using imaging radar datasets from the Japanese Space Agency's ALOS PALSAR and Digital Elevation Models (DEMs) from NASA's Shuttle Radar Topography Mission (SRTM). Results provide an understanding of the underlying geomorphology of the Amazon planalto as well as its relationship to geologic processes and will support interpretation of the evolutionary history of the Amazon Basin. Portions of this work have been carried out within the framework of the ALOS Kyoto & Carbon Initiative. PALSAR data were provided by JAXA/EORC and the Alaska Satellite Facility.This work is carried out with support from the NASA Biodiversity Program and the NSF DIMENSIONS of Biodiversity Program.

  12. Applying of Electrical Imaging Survey (EIS) to Evaluate Leachate Pollution in Underground Area of Informal Landfill

    DEFF Research Database (Denmark)

    Du, Song; Wang, Di; Mou, Zishen

    2014-01-01

    An informal landfill is an open dump that pollutes the underground environment because it lacks an impervious liner. The leakage of such a landfill is unidirectional and thus difficult to directly test. This study uses electrical imaging survey to evaluate the pollution of the underground...... environment of an informal landfill for municipal solid waste in Beijing. We hypothesize that every location has a specific resistivity resulting from the leachate. We use the membership function of fuzzy mathematics to quantitatively represent the pollution of the underground environment in the sanitary...... landfill. The results are consistent with borehole data....

  13. Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra

    Energy Technology Data Exchange (ETDEWEB)

    Cukras, Janusz; Coriani, Sonia; Decleva, Piero [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, via L. Giorgieri 1, I-34127 Trieste (Italy); Christiansen, Ove [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Norman, Patrick [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden)

    2013-09-07

    A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H{sub 2}, H{sub 2}O, NH{sub 3}, HF, CO, and CO{sub 2}.

  14. Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra

    Science.gov (United States)

    Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick

    2013-09-01

    A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H2, H2O, NH3, HF, CO, and CO2.

  15. Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra

    International Nuclear Information System (INIS)

    Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick

    2013-01-01

    A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H 2 , H 2 O, NH 3 , HF, CO, and CO 2

  16. Digital Image Correlation Techniques Applied to Large Scale Rocket Engine Testing

    Science.gov (United States)

    Gradl, Paul R.

    2016-01-01

    Rocket engine hot-fire ground testing is necessary to understand component performance, reliability and engine system interactions during development. The J-2X upper stage engine completed a series of developmental hot-fire tests that derived performance of the engine and components, validated analytical models and provided the necessary data to identify where design changes, process improvements and technology development were needed. The J-2X development engines were heavily instrumented to provide the data necessary to support these activities which enabled the team to investigate any anomalies experienced during the test program. This paper describes the development of an optical digital image correlation technique to augment the data provided by traditional strain gauges which are prone to debonding at elevated temperatures and limited to localized measurements. The feasibility of this optical measurement system was demonstrated during full scale hot-fire testing of J-2X, during which a digital image correlation system, incorporating a pair of high speed cameras to measure three-dimensional, real-time displacements and strains was installed and operated under the extreme environments present on the test stand. The camera and facility setup, pre-test calibrations, data collection, hot-fire test data collection and post-test analysis and results are presented in this paper.

  17. Numerical images applied to the spatial technics: the discovery of the Halley's comet nucleus

    International Nuclear Information System (INIS)

    Abergel, A.

    1988-01-01

    For the first time, the solide nucleus of a comet was observed by the 2 soviet spacecraft VEGA on 6 and 9 March 1986. They were followed by the european spacecraft GIOTTO on 14 march. The numerical images transmitted by the 3 spacecraft have been corrected from instrumental degradations and allowed a unique description of the shape and the movement of Halley's comet nucleus. Thus the contours become clearly apparent. Its volume can be described by an ellipsoid which principal axis are equal to 16, 8.2 and 7.5 km: it has an oblate rugby balloon shape. Its rational movement is complicated, but we are able to analyse it with the identification of details seen on the surface at three different moments. The nucleus is greater than expected in the past. It is made of a mixture of water ice and dust, and is covered by a dust dark mantle: it is one of the darkest objects in the solar system. This mantle is not uniform, as shown by the images sent by the 3 spacecraft. They display a spectacular distribution of dust jets emitted by very active regions on the nucleus surface [fr

  18. Point Analysis in Java applied to histological images of the perforant pathway: a user's account.

    Science.gov (United States)

    Scorcioni, Ruggero; Wright, Susan N; Patrick Card, J; Ascoli, Giorgio A; Barrionuevo, Germán

    2008-01-01

    The freeware Java tool Point Analysis in Java (PAJ), created to perform 3D point analysis, was tested in an independent laboratory setting. The input data consisted of images of the hippocampal perforant pathway from serial immunocytochemical localizations of the rat brain in multiple views at different resolutions. The low magnification set (x2 objective) comprised the entire perforant pathway, while the high magnification set (x100 objective) allowed the identification of individual fibers. A preliminary stereological study revealed a striking linear relationship between the fiber count at high magnification and the optical density at low magnification. PAJ enabled fast analysis for down-sampled data sets and a friendly interface with automated plot drawings. Noted strengths included the multi-platform support as well as the free availability of the source code, conducive to a broad user base and maximum flexibility for ad hoc requirements. PAJ has great potential to extend its usability by (a) improving its graphical user interface, (b) increasing its input size limit, (c) improving response time for large data sets, and (d) potentially being integrated with other Java graphical tools such as ImageJ.

  19. GPR image analysis to locate water leaks from buried pipes by applying variance filters

    Science.gov (United States)

    Ocaña-Levario, Silvia J.; Carreño-Alvarado, Elizabeth P.; Ayala-Cabrera, David; Izquierdo, Joaquín

    2018-05-01

    Nowadays, there is growing interest in controlling and reducing the amount of water lost through leakage in water supply systems (WSSs). Leakage is, in fact, one of the biggest problems faced by the managers of these utilities. This work addresses the problem of leakage in WSSs by using GPR (Ground Penetrating Radar) as a non-destructive method. The main objective is to identify and extract features from GPR images such as leaks and components in a controlled laboratory condition by a methodology based on second order statistical parameters and, using the obtained features, to create 3D models that allows quick visualization of components and leaks in WSSs from GPR image analysis and subsequent interpretation. This methodology has been used before in other fields and provided promising results. The results obtained with the proposed methodology are presented, analyzed, interpreted and compared with the results obtained by using a well-established multi-agent based methodology. These results show that the variance filter is capable of highlighting the characteristics of components and anomalies, in an intuitive manner, which can be identified by non-highly qualified personnel, using the 3D models we develop. This research intends to pave the way towards future intelligent detection systems that enable the automatic detection of leaks in WSSs.

  20. Time integration and statistical regulation applied to mobile objects detection in a sequence of images

    International Nuclear Information System (INIS)

    Letang, Jean-Michel

    1993-01-01

    This PhD thesis deals with the detection of moving objects in monocular image sequences. The first section presents the inherent problems of motion analysis in real applications. We propose a method robust to perturbations frequently encountered during acquisition of outdoor scenes. It appears three main directions for investigations, all of them pointing out the importance of the temporal axis, which is a specific dimension for motion analysis. In the first part, the image sequence is considered as a set of temporal signals. The temporal multi-scale decomposition enables the characterization of various dynamical behaviors of the objects being in the scene at a given instant. A second module integrates motion information. This elementary trajectography of moving objects provides a temporal prediction map, giving a confidence level of motion presence. Interactions between both sets of data are expressed within a statistical regularization. Markov random field models supply a formal framework to convey a priori knowledge of the primitives to be evaluated. A calibration method with qualitative boxes is presented to estimate model parameters. Our approach requires only simple computations and leads to a rather fast algorithm, that we evaluate in the last section over various typical sequences. (author) [fr

  1. Acoustic Territoriality

    DEFF Research Database (Denmark)

    Kreutzfeldt, Jacob

    2011-01-01

    Under the heading of "Gang i København" a number of initiatives was presented by the Lord Mayer and the Technical and Environmental Mayer of Copenhagen in May 2006. The aim of the initiative, which roughly translates to Lively Copenhagen, was both to make Copenhagen a livelier city in terms of city...... this article outline a few approaches to a theory of acoustic territoriality....

  2. Acoustic lenses

    International Nuclear Information System (INIS)

    Kittmer, C.A.

    1983-03-01

    Acoustic lenses focus ultrasound to produce pencil-like beams with reduced near fields. When fitted to conventional (flat-faced) transducers, such lenses greatly improve the ability to detect and size defects. This paper describes a program developed to design acoustic lenses for use in immersion or contact inspection, using normal or angle beam mode with flat or curved targets. Lens surfaces are circular in geometry to facilitate machining. For normal beam inspection of flat plate, spherical or cylindrical lenses are used. For angle beam or curved surface inspections, a compound lens is required to correct for the extra induced aberration. Such a lens is aspherical with one radius of curvature in the plane of incidence, and a different radius of curvature in the plane perpendicular to the incident plane. The resultant beam profile (i.e., location of the acoustic focus, beam diameter, 6 dB working range) depends on the degree of focusing and the transducer used. The operating frequency and bandwidth can be affected by the instrumentation used. Theoretical and measured beam profiles are in good agreement. Various applications, from zone focusing used for defect sizing in thick plate, to line focusing for pipe weld inspection, are discussed

  3. Non-invasive imaging methods applied to neo- and paleontological cephalopod research

    Science.gov (United States)

    Hoffmann, R.; Schultz, J. A.; Schellhorn, R.; Rybacki, E.; Keupp, H.; Gerden, S. R.; Lemanis, R.; Zachow, S.

    2013-11-01

    Several non-invasive methods are common practice in natural sciences today. Here we present how they can be applied and contribute to current topics in cephalopod (paleo-) biology. Different methods will be compared in terms of time necessary to acquire the data, amount of data, accuracy/resolution, minimum-maximum size of objects that can be studied, of the degree of post-processing needed and availability. Main application of the methods is seen in morphometry and volumetry of cephalopod shells in order to improve our understanding of diversity and disparity, functional morphology and biology of extinct and extant cephalopods.

  4. Online monitoring of the two-dimensional temperature field in a boiler furnace based on acoustic computed tomography

    International Nuclear Information System (INIS)

    Zhang, Shiping; Shen, Guoqing; An, Liansuo; Niu, Yuguang

    2015-01-01

    Online monitoring of the temperature field is crucial to optimally adjust combustion within a boiler. In this paper, acoustic computed tomography (CT) technology was used to obtain the temperature profile of a furnace cross-section. The physical principles behind acoustic CT, acoustic signals and time delay estimation were studied. Then, the technique was applied to a domestic 600-MW coal-fired boiler. Acoustic CT technology was used to monitor the temperature field of the cross-section in the boiler furnace, and the temperature profile was reconstructed through ART iteration. The linear sweeping frequency signal was adopted as the sound source signal, whose sweeping frequency ranged from 500 to 3000 Hz with a sweeping cycle of 0.1 s. The generalized cross-correlation techniques with PHAT and ML were used as the time delay estimation method when the boiler was in different states. Its actual operation indicated that the monitored images accurately represented the combustion state of the boiler, and the acoustic CT system was determined to be accurate and reliable. - Highlights: • An online monitoring approach to monitor temperature field in a boiler furnace. • The paper provides acoustic CT technology to obtain the temperature profile of a furnace cross-section. • The temperature profile was reconstructed through ART iteration. • The technique is applied to a domestic 600-MW coal-fired boiler. • The monitored images accurately represent the combustion state of the boiler

  5. Evaluation of damage accumulation behavior and strength anisotropy of NITE SiC/SiC composites by acoustic emission, digital image correlation and electrical resistivity monitoring

    International Nuclear Information System (INIS)

    Nozawa, Takashi; Ozawa, Kazumi; Asakura, Yuuki; Kohyama, Akira; Tanigawa, Hiroyasu

    2014-01-01

    Understanding the cracking process of the composites is essential to establish the design basis for practical applications. This study aims to investigate the damage accumulation process and its anisotropy for nano-infiltration transient eutectic sintered (NITE) SiC/SiC composites by various characterization techniques such as the acoustic emission (AE), digital image correlation (DIC) and electrical resistivity (ER) measurements. Cracking behavior below the proportional limit stress (PLS) was specifically addressed. Similar to the other generic SiC/SiC composites, the 1st AE event was identified below the PLS for NITE SiC/SiC composites with a dependency of fabric orientation. The DIC results support that the primary failure mode depending on fiber orientation affected more than the other minor modes did. Detailed AE waveform analysis by wavelet shows a potential to classify the failure behavior depending on architecture. Cracking below the PLS is a potential concern in component deign but the preliminary ER measurements imply that the impact of cracking below the PLS on composite function was limited

  6. Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging

    International Nuclear Information System (INIS)

    Guzman-Aroca, F.; Reus, M.; Dios Berna-Serna, Juan de; Frutos-Bernal, M.D.; Lujan-Mompean, J.A.; Parrilla, P.; Bas, A.

    2012-01-01

    To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery. Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis. The median SWV was 1.57 ± 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 ± 0.90 m/s, 1.55 ± 0.79 m/s and 1.86 ± 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %). The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity. (orig.)

  7. Detection of non-alcoholic steatohepatitis in patients with morbid obesity before bariatric surgery: preliminary evaluation with acoustic radiation force impulse imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Aroca, F.; Reus, M.; Dios Berna-Serna, Juan de [Virgen de la Arrixaca University Hospital, Department of of Radiology, El Palmar, Murcia (Spain); Frutos-Bernal, M.D.; Lujan-Mompean, J.A.; Parrilla, P. [Virgen de la Arrixaca University Hospital, Department of Surgery, El Palmar, Murcia (Spain); Bas, A. [Virgen de la Arrixaca University Hospital, Department of Pathology, El Palmar, Murcia (Spain)

    2012-11-15

    To investigate the utility of acoustic radiation force impulse (ARFI) imaging, with the determination of shear wave velocity (SWV), to differentiate non-alcoholic fatty liver disease (NAFLD) from non-alcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery. Thirty-two patients with morbid obesity were evaluated with ARFI and conventional ultrasound before bariatric surgery. The ARFI and ultrasound results were compared with liver biopsy findings, which is the reference standard. The patients were classed according to their histological findings into three groups: group A, simple steatosis; group B, inflammation; and group C, fibrosis. The median SWV was 1.57 {+-} 0.79 m/s. Hepatic alterations were observed in the histopathological findings for all the patients in the study (100 %), with the results of the laboratory tests proving normal. Differences in SWV were also observed between groups A, B and C: 1.34 {+-} 0.90 m/s, 1.55 {+-} 0.79 m/s and 1.86 {+-} 0.75 m/s (P < 0.001), respectively. The Az for differentiating NAFLD from NASH or fibrosis was 0.899 (optimal cut-off value 1.3 m/s; sensitivity 85 %; specificity 83.3 %). The ARFI technique is a useful diagnostic tool for differentiating NAFLD from NASH in asymptomatic patients with morbid obesity. (orig.)

  8. Progress and Potential of Imaging Mass Spectrometry Applied to Biomarker Discovery.

    Science.gov (United States)

    Quanico, Jusal; Franck, Julien; Wisztorski, Maxence; Salzet, Michel; Fournier, Isabelle

    2017-01-01

    Mapping provides a direct means to assess the impact of protein biomarkers and puts into context their relevance in the type of cancer being examined. To this end, mass spectrometry imaging (MSI) was developed to provide the needed spatial information which is missing in traditional liquid-based mass spectrometric proteomics approaches. Aptly described as a "molecular histology" technique, MSI gives an additional dimension in characterizing tumor biopsies, allowing for mapping of hundreds of molecules in a single analysis. A decade of developments focused on improving and standardizing MSI so that the technique can be translated into the clinical setting. This review describes the progress made in addressing the technological development that allows to bridge local protein detection by MSI to its identification and to illustrate its potential in studying various aspects of cancer biomarker discovery.

  9. The use of lidar images in Costa Rica : case studies applied in geology, engineering, and archaeology

    International Nuclear Information System (INIS)

    Ruiz, Paulo; Garro, Jose F.; Soto, Gerardo J.

    2014-01-01

    A historical review is made about evolution of technology Lidar (Laser Imaging Detection and Ranging). The improvements of this technology and additions from other technologies are annotated in the last 15 years. The information of the aerial and terrestrial lidar operation, technical parameters for data acquisition and resolutions are presented. The results from four studies are presented in Costa Rica: 1) The discovery of pre-Columbian trails in the area of Volcan Arenal, 2) A case of geological mapping and discovery of new volcanic structures in the North area of the Volcan Poas, 3) The characterization of a landslide near Palmares that represents a hazard for the road network, 4) A detail survey of a pre-Columbian sphere. The results from new Lidar will become more frequent in the following years because its cost will be more affordable. The transference of data between institutions will generate new applications in different fields. (author) [es

  10. Advanced GPR imaging of sedimentary features: integrated attribute analysis applied to sand dunes

    Science.gov (United States)

    Zhao, Wenke; Forte, Emanuele; Fontolan, Giorgio; Pipan, Michele

    2018-04-01

    We evaluate the applicability and the effectiveness of integrated GPR attribute analysis to image the internal sedimentary features of the Piscinas Dunes, SW Sardinia, Italy. The main objective is to explore the limits of GPR techniques to study sediment-bodies geometry and to provide a non-invasive high-resolution characterization of the different subsurface domains of dune architecture. On such purpose, we exploit the high-quality Piscinas data-set to extract and test different attributes of the GPR trace. Composite displays of multi-attributes related to amplitude, frequency, similarity and textural features are displayed with overlays and RGB mixed models. A multi-attribute comparative analysis is used to characterize different radar facies to better understand the characteristics of internal reflection patterns. The results demonstrate that the proposed integrated GPR attribute analysis can provide enhanced information about the spatial distribution of sediment bodies, allowing an enhanced and more constrained data interpretation.

  11. Linear, Transfinite and Weighted Method for Interpolation from Grid Lines Applied to OCT Images

    DEFF Research Database (Denmark)

    Lindberg, Anne-Sofie Wessel; Jørgensen, Thomas Martini; Dahl, Vedrana Andersen

    2018-01-01

    of a square grid, but are unknown inside each square. To view these values as an image, intensities need to be interpolated at regularly spaced pixel positions. In this paper we evaluate three methods for interpolation from grid lines: linear, transfinite and weighted. The linear method does not preserve...... and the stability of the linear method further away. An important parameter influencing the performance of the interpolation methods is the upsampling rate. We perform an extensive evaluation of the three interpolation methods across a range of upsampling rates. Our statistical analysis shows significant difference...... in the performance of the three methods. We find that the transfinite interpolation works well for small upsampling rates and the proposed weighted interpolation method performs very well for all upsampling rates typically used in practice. On the basis of these findings we propose an approach for combining two OCT...

  12. Multi-image screening technique applied to a general orientation training program

    International Nuclear Information System (INIS)

    Hajek, B.K.; Campbell, T.O.; Evans, A.D.; Hickey, J.M.

    1979-01-01

    A general orientation and training program is a prerequisite for personnel to have unescorted access to various site locations at a nuclear power plant. A new general orientation and training program is being developed for the Toledo Edison Company to be used at the Davis-Besse Nuclear Power Station. The program is presented in a multi-image and stereo sound format that has the unique capability to present the magnitude and scale of the plant, to arouse and maintain the interest of the viewer, and to instill in him a feeling of importance and pride about his job. Satisfactory completion of the program by individuals is assessed and certified by a machine scored test that is administered as an integral part of the presentation

  13. An automated form of video image analysis applied to classification of movement disorders.

    Science.gov (United States)

    Chang, R; Guan, L; Burne, J A

    Video image analysis is able to provide quantitative data on postural and movement abnormalities and thus has an important application in neurological diagnosis and management. The conventional techniques require patients to be videotaped while wearing markers in a highly structured laboratory environment. This restricts the utility of video in routine clinical practise. We have begun development of intelligent software which aims to provide a more flexible system able to quantify human posture and movement directly from whole-body images without markers and in an unstructured environment. The steps involved are to extract complete human profiles from video frames, to fit skeletal frameworks to the profiles and derive joint angles and swing distances. By this means a given posture is reduced to a set of basic parameters that can provide input to a neural network classifier. To test the system's performance we videotaped patients with dopa-responsive Parkinsonism and age-matched normals during several gait cycles, to yield 61 patient and 49 normal postures. These postures were reduced to their basic parameters and fed to the neural network classifier in various combinations. The optimal parameter sets (consisting of both swing distances and joint angles) yielded successful classification of normals and patients with an accuracy above 90%. This result demonstrated the feasibility of the approach. The technique has the potential to guide clinicians on the relative sensitivity of specific postural/gait features in diagnosis. Future studies will aim to improve the robustness of the system in providing accurate parameter estimates from subjects wearing a range of clothing, and to further improve discrimination by incorporating more stages of the gait cycle into the analysis.

  14. Improved total variation-based CT image reconstruction applied to clinical data

    Energy Technology Data Exchange (ETDEWEB)

    Ritschl, Ludwig; Bergner, Frank; Kachelriess, Marc [Institute of Medical Physics (IMP), University of Erlangen-Nuernberg, Henkestr. 91, 91052 Erlangen (Germany); Fleischmann, Christof, E-mail: ludwig.ritschl@imp.uni-erlangen.de [Ziehm Imaging GmbH, Donaustrasse 31, 90451 Nuernberg (Germany)

    2011-03-21

    In computed tomography there are different situations where reconstruction has to be performed with limited raw data. In the past few years it has been shown that algorithms which are based on compressed sensing theory are able to handle incomplete datasets quite well. As a cost function these algorithms use the l{sub 1}-norm of the image after it has been transformed by a sparsifying transformation. This yields to an inequality-constrained convex optimization problem. Due to the large size of the optimization problem some heuristic optimization algorithms have been proposed in the past few years. The most popular way is optimizing the raw data and sparsity cost functions separately in an alternating manner. In this paper we will follow this strategy and present a new method to adapt these optimization steps. Compared to existing methods which perform similarly, the proposed method needs no a priori knowledge about the raw data consistency. It is ensured that the algorithm converges to the lowest possible value of the raw data cost function, while holding the sparsity constraint at a low value. This is achieved by transferring the step-size determination of both optimization procedures into the raw data domain, where they are adapted to each other. To evaluate the algorithm, we process measured clinical datasets. To cover a wide field of possible applications, we focus on the problems of angular undersampling, data lost due to metal implants, limited view angle tomography and interior tomography. In all cases the presented method reaches convergence within less than 25 iteration steps, while using a constant set of algorithm control parameters. The image artifacts caused by incomplete raw data are mostly removed without introducing new effects like staircasing. All scenarios are compared to an existing implementation of the ASD-POCS algorithm, which realizes the step-size adaption in a different way. Additional prior information as proposed by the PICCS algorithm

  15. Visualization of Protease Activity In Vivo Using an Activatable Photo-Acoustic Imaging Probe Based on CuS Nanoparticles

    Science.gov (United States)

    Yang, Kai; Zhu, Lei; Nie, Liming; Sun, Xiaolian; Cheng, Liang; Wu, Chenxi; Niu, Gang; Chen, Xiaoyuan; Liu, Zhuang

    2014-01-01

    Herein, we for the first time report a novel activatable photoacoustic (PA) imaging nano-probe for in vivo detection of cancer-related matrix metalloproteinases (MMPs). A black hole quencher 3 (BHQ3) which absorbs red light is conjugated to near-infrared (NIR)-absorbing copper sulfide (CuS) nanoparticles via a MMP-cleavable peptide linker. The obtained CuS-peptide-BHQ3 (CPQ) nano-probe exhibits two distinctive absorption peaks at 630 nm and 930 nm. Inside the tumor microenviorment where MMPs present, the MMP-sensitive peptide would be cleaved, releasing BHQ3 from the CuS nanoparticles, the former of which as a small molecule is then rapidly cleared out from the tumor, whereas the latter of which as large nanoparticles would retain inside the tumor for a much longer period of time. As the result, the PA signal at 680 nm which is contributed by BHQ3 would be quickly diminished while that at 930 nm would be largely retained. The PA signal ratio of 680 nm / 930 nm could thus serve as an in vivo indicator of MMPs activity inside the tumor. Our work presents a novel strategy of in vivo sensing of MMPs based on PA imaging, which should offer remarkably improved detection depth compared with traditional optical imaging techniques. PMID:24465271

  16. Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Phased arrays, ultrasonic imaging and nonlinear acoustics

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Tadeusz (ed.); Ping Wu; Wennerstroem, Erik [Uppsala Univ. (Sweden). Signals and Systems

    2004-09-01

    This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2003/2004. After a short introduction a review of beam forming fundamentals required for proper understanding phased array operation is included. The factors that determine lateral resolution during ultrasonic imaging of flaws in solids are analyzed and results of simulations modelling contact inspection of copper are presented. In the second chapter an improved synthetic aperture imaging (SAI) technique is introduced. The proposed SAI technique is characterized by an enhanced lateral resolution compared with the previously proposed extended synthetic aperture focusing technique (ESAFT). The enhancement of imaging performance is achieved due to more realistic assumption concerning the probability density function of scatterers in the region of interest. The proposed technique takes the form of a two-step algorithm using the result obtained in the first step as a prior for the second step. Final chapter contains summary of our recent experimental and theoretical research on nonlinear ultrasonics of unbounded interfaces. A new theoretical model for rough interfaces is developed, and the experimental results from the copper specimens that mimic contact cracks of different types are presented. Derivation of the theory and selected measurement results are given in appendix.

  17. Image intelligence online consulting: A flexible and remote access to strategic information applied to verification of declaration

    International Nuclear Information System (INIS)

    Chassy, A.F. de; Denizot, L.

    2001-01-01

    Commercial satellite imagery is giving International Institutions specialized Information Departments access to a great source of valuable intelligence. High resolution and multiple sensors have also led to a growing complexity of interpretation that calls for a greater need of consulting, verification and training in the field in order to make it eligible as an operational source of verification. Responding to this need, Fleximage is extending its Image intelligence (IMINT) training program to include a fully operational and flexible online consulting and training program. Image Intelligence (IMINT) Online Program, a new approach to acquiring IMINT expertise, supported by Internet technologies, and managed by a professional team of experts and technical staff. Fleximage has developed a virtual learning environment on the Internet for acquiring IMINT expertise. Called the IMINT Online Program, this dynamic learning environment provides complete flexibility and personalization of the process for acquiring expertise. The IMINT online program includes two services: Online Consulting and Online Training. The Online Consulting service is designed for the technical staff of an organization who are already operational in the field of image intelligence. Online Consulting enables these staff members to acquire pertinent expertise online that can be directly applied to their professional activity, such as IAEA verification tasks. The Online Training service is designed for the technical staff of an organization who are relatively new to the field of image intelligence. These staff members need to build expertise within a formal training program. Online Training is a flexible and structured program for acquiring IMINT expertise online

  18. Anomalous acoustic dispersion in architected microlattice metamaterials

    Science.gov (United States)

    KröDel, Sebastian; Palermo, Antonio; Daraio, Chiara

    The ability to control dispersion in acoustic metamaterials is crucial to realize acoustic filtering and rectification devices as well as perfect imaging using negative refractive index materials. Architected microlattice metamaterials immersed in fluid constitute a versatile platform for achieving such control. We investigate architected microlattice materials able to exploit locally resonant modes of their fundamental building blocks that couple with propagating acoustic waves. Using analytical, numerical and experimental methods we find that such lattice materials show a hybrid dispersion behavior governed by Biot's theory for long wavelengths and multiple scattering theory when wave frequency is close to the resonances of the building block. We identify the relevant geometric parameters to alter and control the group and phase velocities in this class of acoustic metamaterials. Furthermore, we fabricate small-scale acoustic metamaterial samples using high precision SLA additive manufacturing and test the resulting materials experimentally using a customized ultrasonic setup. This work paves the way for new acoustic devices based on microlattice metamaterials.

  19. Research on imaging, sensing, and characterization of cells at Research Center for Applied Sciences (RCAS), Academia Sinica

    Science.gov (United States)

    Tsai, Hui-Chen; Chang, Chun-Fang; Chen, Bi-Chang; Cheng, Ji-Yen; Chu, Chih-Wei; Han, Hsieh-Cheng; Hatanaka, Koji; Hsieh, Tung-Han; Lee, Chau-Hwang; Lin, Jung-Hsin; Tung, Yi-Chung; Wei, Pei-Kuen; Yang, Fu-Liang; Tsai, Din Ping

    2015-12-01

    Development of imaging, sensing, and characterization of cells at Research Center for Applied Sciences (RCAS) of Academia Sinica in Taiwan is progressing rapidly. The research on advanced lattice light sheet microscopy for temporal visualization of cells in three dimensions at sub-cellular resolution shows novel imaging results. Label-free observation on filopodial dynamics provides a convenient assay on cancer cell motility. The newly-developed software enables us to track the movement of two types of particles through different channels and reconstruct the co-localized tracks. Surface plasmon resonance (SPR) for detecting urinary microRNA for diagnosis of acute kidney injury demonstrates excellent sensitivity. A fully automated and integrated portable reader was constructed as a home-based surveillance system for post-operation hepatocellular carcinoma. New microfluidic cell culture devices for fast and accurate characterizations prove various diagnosis capabilities.

  20. Application of Acoustic Radiation Force Impulse (ARFI) Elastography in Imaging of Delayed Onset Muscle Soreness (DOMS): A Comparative Analysis With 3T MRI.

    Science.gov (United States)

    Hotfiel, Thilo; Kellermann, Marion; Swoboda, Bernd; Wildner, Dane; Golditz, Tobias; Grim, Casper; Raithel, Martin; Uder, Michael; Heiss, Rafael

    2017-05-17

    DOMS is one of the most common reasons for impaired muscle performance in sports and is associated with reduced muscle strength and frequently observed both in professional and recreational athletes. To emphasize the diagnostic value of Acoustic Radiation Force Impulse (ARFI) in imaging of Delayed Onset Muscle Soreness by comparing findings to high-resolution 3T MRI T2 weighted sequences. Case series. Laboratory environment. Fifteen healthy students (7 female, 8 male, age 24 ± 4 years, height 178 ± 10 cm, body weight 67 ± 12 kg). ARFI values, represented as shear wave velocities (SWV) of the gastrocnemius muscle (GM) and soleus muscle (SM), as well as conventional ultrasound, high-resolution 3T MRI, creatine kinase activity, extension range of the ankle joint, calf circumference and muscle soreness were assessed before (baseline) and 60 hours after (post-intervention, PI) a standardized eccentric exercise. ARFI SWV values of the GM revealed a statistically significant decrease of 19.1% between baseline (2.2 ± 0.26 m/s) and PI (1.78 ± 0.24 m/s); p = 0.008. At follow-up, the MRI investigations showed intramuscular oedema for the GM in all participants corresponding to a significant raise in T2 signal intensity (p = 0.001) and in T2-time values (p = 0.004). ARFI elastography seems to be an additional sensitive diagnostic modality in the diagnostic work up of DOMS. Intramuscular SWV could represent an additional imaging marker for the assessment and monitoring of ultrastructural muscle injuries and therefore be helpful for individual training composition in elite sports.

  1. Non-intrusive telemetry applications in the oilsands: from visible light and x-ray video to acoustic imaging and spectroscopy

    Science.gov (United States)

    Shaw, John M.

    2013-06-01

    While the production, transport and refining of oils from the oilsands of Alberta, and comparable resources elsewhere is performed at industrial scales, numerous technical and technological challenges and opportunities persist due to the ill defined nature of the resource. For example, bitumen and heavy oil comprise multiple bulk phases, self-organizing constituents at the microscale (liquid crystals) and the nano scale. There are no quantitative measures available at the molecular level. Non-intrusive telemetry is providing promising paths toward solutions, be they enabling technologies targeting process design, development or optimization, or more prosaic process control or process monitoring applications. Operation examples include automated large object and poor quality ore during mining, and monitoring the thickness and location of oil water interfacial zones within separation vessels. These applications involve real-time video image processing. X-ray transmission video imaging is used to enumerate organic phases present within a vessel, and to detect individual phase volumes, densities and elemental compositions. This is an enabling technology that provides phase equilibrium and phase composition data for production and refining process development, and fluid property myth debunking. A high-resolution two-dimensional acoustic mapping technique now at the proof of concept stage is expected to provide simultaneous fluid flow and fluid composition data within porous inorganic media. Again this is an enabling technology targeting visualization of diverse oil production process fundamentals at the pore scale. Far infrared spectroscopy coupled with detailed quantum mechanical calculations, may provide characteristic molecular motifs and intermolecular association data required for fluid characterization and process modeling. X-ray scattering (SAXS/WAXS/USAXS) provides characteristic supramolecular structure information that impacts fluid rheology and process

  2. Acoustic Radiation Force Impulse Imaging for the Differentiation of Benign and Malignant Lymph Nodes: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Zhang, Peige; Zhang, Li; Zheng, Shaoping; Yu, Cheng; Xie, Mingxing; Lv, Qing

    2016-01-01

    To evaluate the overall performance of acoustic radiation force impulse imaging (ARFI) in differentiating between benign and malignant lymph nodes (LNs) by conducting a meta-analysis. PubMed, Embase, Web of Science, the Cochrane Library and the China National Knowledge Infrastructure were comprehensively searched for potential studies through August 13th, 2016. Studies that investigated the diagnostic power of ARFI for the differential diagnosis of benign and malignant LNs by using virtual touch tissue quantification (VTQ) or virtual touch tissue imaging quantification (VTIQ) were collected. The included articles were published in English or Chinese. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to evaluate the methodological quality. The pooled sensitivity, specificity, and the area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated by means of a bivariate mixed-effects regression model. Meta-regression analysis was performed to identify the potential sources of between study heterogeneity. Fagan plot analysis was used to explore the clinical utilities. Publication bias was assessed using Deek's funnel plot. Nine studies involving 1084 LNs from 929 patients were identified to analyze in the meta-analysis. The summary sensitivity and specificity of ARFI in detecting malignant LNs were 0.87 (95% confidence interval [CI], 0.83-0.91) and 0.88 (95% CI, 0.82-0.92), respectively. The AUC was 0.93 (95% CI, 0.90-0.95). The pooled DOR was 49.59 (95% CI, 26.11-94.15). Deek's funnel plot revealed no significant publication bias. ARFI is a promising tool for the differentiation of benign and malignant LNs with high sensitivity and specificity.

  3. [Contrastive study on conventional ultrasound, compression elastography and acoustic radiation force impulse imaging in the differential diagnosis of benign and malignant breast tumors].

    Science.gov (United States)

    Zhang, Lu; Zhou, Ping; Deng, Jin; Tian, Shuangming; Qian, Ying; Wu, Xiaomin; Ma, Shuhua; Li, Jiale

    2014-12-01

    To evaluate the diagnostic performance of conventional ultrasound, compression elastography (CE) and acoustic radiation force impulse imaging (ARFI) in differential diagnosis of benign and malignant breast tumors. A total of 98 patients with liver lesions were included in the study. The images of conventional ultrasound, CE and the values of virtual touch tissue quantification (VTQ) of breast lesions were obtained. The diagnostic performance of conventional ultrasound, CE and ARFI were assessed by using pathology as the gold standard, and then evaluate the diagnosis efficiency of these three approaches in differential diagnosing benign and malignant breast tumors. The specificity, sensitivity and accuracy in the diagnosis of malignant breast tumors for conventional ultrasound were 80.0%, 81.1% and 81.7%, respectively, whereas for CE elastic score were 85.7%, 86.7% and 86.3%, respectively. With a cutoff value of 3.71 for the SR, the sensitivity, specificity, accuracy in diagnosis of malignant breast tumors were 97.1%, 83.3% and 88.4%, respectively. With a cutoff value of 3.78 m/s for VTQ, the sensitivity, specificity, accuracy in diagnosis of malignant breast tumors were 94.3%, 91.7% and 92.6%, respectively. The difference in diagnosis efficiency among ARFI, CE and conventional ultrasound in differential diagnosis of benign and malignant breast tumors was significant (Pbenign and malignant breast tumors. But the diagnosis efficiency of ARFI is superior to CE and conventional ultrasound. The three approaches can help each other in differential diagnosis of benign and malignant breast tumors.

  4. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Solar Dynamics Observatory-Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, Thomas L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2010-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler-velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time - distance helioseismology pipeline (Zhao et al., Solar Phys. submitted, 2010) has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross-covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time - distance helioseismology: a Gabor-wavelet fitting (Kosovichev and Duvall, SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, Astrophys. J. 571, 966, 2002), and a linearized version of the minimization method (Gizon and Birch, Astrophys. J. 614, 472, 2004). Using Doppler-velocity data from the Michelson Doppler Imager (MDI) instrument onboard SOHO, we tested and compared these definitions for the mean and difference traveltime perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet-Sun region, the method of Gizon and Birch (Astrophys. J. 614, 472, 2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (SCORE'96: Solar Convection and Oscillations and Their Relationship, ASSL, Dordrecht, 241, 1997) and Gizon and Birch (Astrophys. J. 571, 966, 2002). We investigated the relationships among

  5. Implementation and Comparison of Acoustic Travel-Time Measurement Procedures for the Helioseismic and Magnetic Imager Time-Distance Helioseismology Pipeline

    Science.gov (United States)

    Couvidat, S.; Zhao, J.; Birch, A. C.; Kosovichev, A. G.; Duvall, T. L., Jr.; Parchevsky, K.; Scherrer, P. H.

    2009-01-01

    The Helioseismic and Magnetic Imager (HMI) instrument on board the Solar Dynamics Observatory (SDO) satellite is designed to produce high-resolution Doppler velocity maps of oscillations at the solar surface with high temporal cadence. To take advantage of these high-quality oscillation data, a time-distance helioseismology pipeline has been implemented at the Joint Science Operations Center (JSOC) at Stanford University. The aim of this pipeline is to generate maps of acoustic travel times from oscillations on the solar surface, and to infer subsurface 3D flow velocities and sound-speed perturbations. The wave travel times are measured from cross covariances of the observed solar oscillation signals. For implementation into the pipeline we have investigated three different travel-time definitions developed in time-distance helioseismology: a Gabor wavelet fitting (Kosovichev and Duvall, 1997), a minimization relative to a reference cross-covariance function (Gizon and Birch, 2002), and a linearized version of the minimization method (Gizon and Birch, 2004). Using Doppler velocity data from the Michelson Doppler Imager (MDI) instrument on board SOHO, we tested and compared these definitions for the mean and difference travel-time perturbations measured from reciprocal signals. Although all three procedures return similar travel times in a quiet Sun region, the method of Gizon and Birch (2004) gives travel times that are significantly different from the others in a magnetic (active) region. Thus, for the pipeline implementation we chose the procedures of Kosovichev and Duvall (1997) and Gizon and Birch (2002). We investigated the relationships among these three travel-time definitions, their sensitivities to fitting parameters, and estimated the random errors they produce

  6. Imaging sciences workshop

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1994-11-15

    This workshop on the Imaging Sciences sponsored by Lawrence Livermore National Laboratory contains short abstracts/articles submitted by speakers. The topic areas covered include the following: Astronomical Imaging; biomedical imaging; vision/image display; imaging hardware; imaging software; Acoustic/oceanic imaging; microwave/acoustic imaging; computed tomography; physical imaging; imaging algorithms. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  7. Nuclear medicine to image applied pathophysiology: Evaluation of reserves by emission computerized tomography

    International Nuclear Information System (INIS)

    Buell, U.; Schicha, H.

    1990-01-01

    Nuclear procedures have long been successful in displaying parameters related to physiological and/or pathophysiological mechanisms inherent in organs or systems. Since a major advantage of PET is its ability to measure actual concentration, we now expect to gain such data in absolute terms. The use of stimuli, however, makes it possible to determine parameters in the form of ratios (stimulus-to-rest). Moreover, these ratios are correlated closely with the capacity of reserve mechanisms experienced from applied pathophysiology, in addition to which some are accessible by means of SPET. The clinical validity of findings related to coronary and cerebrovascular perfusion reserves have already been confirmed by SPET and/or PET. These results, if complemented by parameters of metabolic reserve, would constitute a most powerful tool in functional clinical diagnostics, allowing determination of differences between actual values and critical thresholds. This is one of the most promising approaches exclusively available from PET. (orig.)

  8. Comparison of vessel enhancement algorithms applied to time-of-flight MRA images for cerebrovascular segmentation.

    Science.gov (United States)

    Phellan, Renzo; Forkert, Nils D

    2017-11-01

    Vessel enhancement algorithms are often used as a preprocessing step for vessel segmentation in medical images to improve the overall segmentation accuracy. Each algorithm uses different characteristics to enhance vessels, such that the most suitable algorithm may vary for different applications. This paper presents a comparative analysis of the accuracy gains in vessel segmentation generated by the use of nine vessel enhancement algorithms: Multiscale vesselness using the formulas described by Erdt (MSE), Frangi (MSF), and Sato (MSS), optimally oriented flux (OOF), ranking orientations responses path operator (RORPO), the regularized Perona-Malik approach (RPM), vessel enhanced diffusion (VED), hybrid diffusion with continuous switch (HDCS), and the white top hat algorithm (WTH). The filters were evaluated and compared based on time-of-flight MRA datasets and corresponding manual segmentations from 5 healthy subjects and 10 patients with an arteriovenous malformation. Additionally, five synthetic angiographic datasets with corresponding ground truth segmentation were generated with three different noise levels (low, medium, and high) and also used for comparison. The parameters for each algorithm and subsequent segmentation were optimized using leave-one-out cross evaluation. The Dice coefficient, Matthews correlation coefficient, area under the ROC curve, number of connected components, and true positives were used for comparison. The results of this study suggest that vessel enhancement algorithms do not always lead to more accurate segmentation results compared to segmenting nonenhanced images directly. Multiscale vesselness algorithms, such as MSE, MSF, and MSS proved to be robust to noise, while diffusion-based filters, such as RPM, VED, and HDCS ranked in the top of the list in scenarios with medium or no noise. Filters that assume tubular-shapes, such as MSE, MSF, MSS, OOF, RORPO, and VED show a decrease in accuracy when considering patients with an AVM

  9. Uniaxial experimental study of the acoustic emission and deformation behavior of composite rock based on 3D digital image correlation (DIC)

    Science.gov (United States)

    Cheng, Jian-Long; Yang, Sheng-Qi; Chen, Kui; Ma, Dan; Li, Feng-Yuan; Wang, Li-Ming

    2017-12-01

    In this paper, uniaxial compression tests were carried out on a series of composite rock specimens with different dip angles, which were made from two types of rock-like material with different strength. The acoustic emission technique was used to monitor the acoustic signal characteristics of composite rock specimens during the entire loading process. At the same time, an optical non-contact 3D digital image correlation technique was used to study the evolution of axial strain field and the maximal strain field before and after the peak strength at different stress levels during the loading process. The effect of bedding plane inclination on the deformation and strength during uniaxial loading was analyzed. The methods of solving the elastic constants of hard and weak rock were described. The damage evolution process, deformation and failure mechanism, and failure mode during uniaxial loading were fully determined. The experimental results show that the θ = 0{°}-45{°} specimens had obvious plastic deformation during loading, and the brittleness of the θ = 60{°}-90{°} specimens gradually increased during the loading process. When the anisotropic angle θ increased from 0{°} to 90{°}, the peak strength, peak strain, and apparent elastic modulus all decreased initially and then increased. The failure mode of the composite rock specimen during uniaxial loading can be divided into three categories: tensile fracture across the discontinuities (θ = 0{°}-30{°}), sliding failure along the discontinuities (θ = 45{°}-75{°}), and tensile-split along the discontinuities (θ = 90{°}). The axial strain of the weak and hard rock layers in the composite rock specimen during the loading process was significantly different from that of the θ = 0{°}-45{°} specimens and was almost the same as that of the θ = 60{°}-90{°} specimens. As for the strain localization highlighted in the maximum principal strain field, the θ = 0{°}-30{°} specimens appeared in the rock

  10. 12th Anglo-French Physical Acoustics Conference (AFPAC2013)

    Science.gov (United States)

    2014-04-01

    The Anglo-French Physical Acoustics Conference (AFPAC) had its 12th annual meeting in Villa Clythia, Fréjus, France, from 16th to 18th January 2013. This series of meetings is a collaboration between the Physical Acoustics Group (PAG) of the Institute of Physics and the Groupe d'Acoustique Physique, Sous-marine et UltraSonore (GAPSUS) of the Société Française d'Acoustique. This year, attendees got the opportunity to see the French Riviera with its Mediterranean vegetation covered by a nice thick snow layer. The participants heard 34 excellent oral presentations and saw 3 posters covering an exciting and diverse range of subjects and of frequencies, from ultrasonic wave propagation in chocolate to metamaterials applied to seismic waves for protecting buildings. Among them, invited talks were given by Pr F A Duck ( Enhanced healing by ultrasound: clinical effects and mechanisms), Pr. J-C Valiére, who actually gave two invited talks ( 1. Measurement of audible acoustic particle velocity using laser: Principles, signal processing and applications, 2. Acoustic pots in ancient and medieval buildings: Literary analysis of ancient texts and comparison with recent observations in French churches), Dr P Huthwaite ( Ultrasonic imaging through the resolution of inverse problems), Dr X Lurton ( Underwater acoustic systems on oceanographic research vessels: principles and applications), Dr S Guenneau ( From platonics to seismic metamaterials). For the fifth consecutive year AFPAC is followed by the publication of its proceedings with 12 peer-reviewed papers which cover the most recent research developments in the field of Physical Acoustics in the UK and France. Alain Lhémery (CEA, France) and Nader Saffari (UCL, United Kingdom) French Riviera 12th AFPAC — Villa Clythia, Fréjus (French Riviera), the 17th of January 2013

  11. Effects of subsampling of passive acoustic recordings on acoustic metrics.

    Science.gov (United States)

    Thomisch, Karolin; Boebel, Olaf; Zitterbart, Daniel P; Samaran, Flore; Van Parijs, Sofie; Van Opzeeland, Ilse

    2015-07-01

    Passive acoustic monitoring is an important tool in marine mammal studies. However, logistics and finances frequently constrain the number and servicing schedules of acoustic recorders, requiring a trade-off between deployment periods and sampling continuity, i.e., the implementation of a subsampling scheme. Optimizing such schemes to each project's specific research questions is desirable. This study investigates the impact of subsampling on the accuracy of two common metrics, acoustic presence and call rate, for different vocalization patterns (regimes) of baleen whales: (1) variable vocal activity, (2) vocalizations organized in song bouts, and (3) vocal activity with diel patterns. To this end, above metrics are compared for continuous and subsampled data subject to different sampling strategies, covering duty cycles between 50% and 2%. The results show that a reduction of the duty cycle impacts negatively on the accuracy of both acoustic presence and call rate estimates. For a given duty cycle, frequent short listening periods improve accuracy of daily acoustic presence estimates over few long listening periods. Overall, subsampling effects are most pronounced for low and/or temporally clustered vocal activity. These findings illustrate the importance of informed decisions when applying subsampling strategies to passive acoustic recordings or analyses for a given target species.

  12. Energy-sensitive imaging detector applied to the dissociative recombination of D2H+

    International Nuclear Information System (INIS)

    Buhr, H.; Schwalm, D.; Mendes, M. B.; Novotny, O.; Berg, M. H.; Bing, D.; Krantz, C.; Orlov, D. A.; Sorg, T.; Stuetzel, J.; Varju, J.; Wolf, A.; Heber, O.; Rappaport, M. L.; Zajfman, D.

    2010-01-01

    We report on an energy-sensitive imaging detector for studying the fragmentation of polyatomic molecules in the dissociative recombination of fast molecular ions with electrons. The system is based on a large area (10x10 cm 2 ) position-sensitive, double-sided Si-strip detector with 128 horizontal and 128 vertical strips, whose pulse height information is read out individually. The setup allows us to uniquely identify fragment masses and is thus capable of measuring branching ratios between different fragmentation channels, kinetic energy releases, and breakup geometries as a function of the relative ion-electron energy. The properties of the detection system, which has been installed at the Test Storage Ring (TSR) facility of the Max-Planck Institute for Nuclear Physics in Heidelberg, is illustrated by an investigation of the dissociative recombination of the deuterated triatomic hydrogen cation D 2 H + . A huge isotope effect is observed when comparing the relative branching ratio between the D 2 + H and the HD + D channel; the ratio 2B(D 2 + H)/B(HD + D), which is measured to be 1.27±0.05 at relative electron-ion energies around 0 eV, is found to increase to 3.7±0.5 at ∼5 eV.

  13. Energy-sensitive imaging detector applied to the dissociative recombination of D2H+

    Science.gov (United States)

    Buhr, H.; Mendes, M. B.; Novotný, O.; Schwalm, D.; Berg, M. H.; Bing, D.; Heber, O.; Krantz, C.; Orlov, D. A.; Rappaport, M. L.; Sorg, T.; Stützel, J.; Varju, J.; Wolf, A.; Zajfman, D.

    2010-06-01

    We report on an energy-sensitive imaging detector for studying the fragmentation of polyatomic molecules in the dissociative recombination of fast molecular ions with electrons. The system is based on a large area (10×10 cm2) position-sensitive, double-sided Si-strip detector with 128 horizontal and 128 vertical strips, whose pulse height information is read out individually. The setup allows us to uniquely identify fragment masses and is thus capable of measuring branching ratios between different fragmentation channels, kinetic energy releases, and breakup geometries as a function of the relative ion-electron energy. The properties of the detection system, which has been installed at the Test Storage Ring (TSR) facility of the Max-Planck Institute for Nuclear Physics in Heidelberg, is illustrated by an investigation of the dissociative recombination of the deuterated triatomic hydrogen cation D2H+. A huge isotope effect is observed when comparing the relative branching ratio between the D2 + H and the HD + D channel; the ratio 2B(D2 + H)/B(HD + D), which is measured to be 1.27±0.05 at relative electron-ion energies around 0 eV, is found to increase to 3.7±0.5 at ~5 eV.

  14. Cerebral cortex classification by conditional random fields applied to intraoperative thermal imaging

    Directory of Open Access Journals (Sweden)

    Hoffmann Nico

    2016-09-01

    Full Text Available Intraoperative thermal neuroimaging is a novel intraoperative imaging technique for the characterization of perfusion disorders, neural activity and other pathological changes of the brain. It bases on the correlation of (sub-cortical metabolism and perfusion with the emitted heat of the cortical surface. In order to minimize required computational resources and prevent unwanted artefacts in subsequent data analysis workflows foreground detection is a important preprocessing technique to differentiate pixels representing the cerebral cortex from background objects. We propose an efficient classification framework that integrates characteristic dynamic thermal behaviour into this classification task to include additional discriminative features. The first stage of our framework consists of learning this representation of characteristic thermal time-frequency behaviour. This representation models latent interconnections in the time-frequency domain that cover specific, yet a priori unknown, thermal properties of the cortex. In a second stage these features are then used to classify each pixel’s state with conditional random fields. We quantitatively evaluate several approaches to learning high-level features and their impact to the overall prediction accuracy. The introduction of high-level features leads to a significant accuracy improvement compared to a baseline classifier.

  15. Imaging techniques applied to the study of fluids in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Tomutsa, L.; Doughty, D.; Mahmood, S.; Brinkmeyer, A.; Madden, M.P.

    1991-01-01

    A detailed understanding of rock structure and its influence on fluid entrapment, storage capacity, and flow behavior can improve the effective utilization and design of methods to increase the recovery of oil and gas from petroleum reservoirs. The dynamics of fluid flow and trapping phenomena in porous media was investigated. Miscible and immiscible displacement experiments in heterogeneous Berea and Shannon sandstone samples were monitored using X-ray computed tomography (CT scanning) to determine the effect of heterogeneities on fluid flow and trapping. The statistical analysis of pore and pore throat sizes in thin sections cut from these sandstone samples enabled the delineation of small-scale spatial distributions of porosity and permeability. Multiphase displacement experiments were conducted with micromodels constructed using thin slabs of the sandstones. The combination of the CT scanning, thin section, and micromodel techniques enables the investigation of how variations in pore characteristics influence fluid front advancement, fluid distributions, and fluid trapping. Plugs cut from the sandstone samples were investigated using high resolution nuclear magnetic resonance imaging permitting the visualization of oil, water or both within individual pores. The application of these insights will aid in the proper interpretation of relative permeability, capillary pressure, and electrical resistivity data obtained from whole core studies. 7 refs., 14 figs., 2 tabs.

  16. Acoustic Neuroma Association

    Science.gov (United States)

    ... EVENTS DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic neuroma? Diagnosing ... Brain Freeze ? READ MORE Read More What is acoustic neuroma? Identifying an AN Learn More Get Info ...

  17. Acoustic and Optical Televiewer Borehole Logging

    International Nuclear Information System (INIS)

    Ahmad Hasnulhadi Che Kamaruddin; Nik Marzukee Nik Ibrahim; Zaidi Ibrahim; Nurul Wahida Ahmad Khairuddin; Azmi Ibrahim

    2016-01-01

    This review paper is focused on Borehole Televiewer. Borehole Televiewer or (BHTV) was used to obtain high-resolution acoustical images from the borehole wall. A probe with a high resolution downward looking camera is used. The camera has specific optics (a conical mirror with a ring of bulbs) with just one shot needed to capture the entire borehole circumference as a 360 panoramic view. Settings similar to traditional cameras (exposure, quality, light, frame rate and resolution) make it effective in almost any type of borehole fluid. After each shot, a series of horizontal pixel strings are acquired, giving a rasterized RGB picture in real-time which is transmitted to the console and finally to a monitor. The orientation device embedded in the tool, which is made of 3 inclinometers and 3 magnetometers, allows the inclination and azimuth of the probe to be computed in real-time, correctly orienting the borehole images. Besides, Acoustic and Optical Televiewer has been introduced as its advanced in technological research. Its logging has been successfully applied to geotechnical investigations and mineral exploration (Schepers et al., 2001) due to advances in beam focusing, increased dynamic range, digital recording techniques, and digital data processing (Schepers, 1991). Thus, this paper will go through to the basic principle of (BHTV) as one type of data collection today. (author)

  18. OPTICAL FLOW APPLIED TO TIME-LAPSE IMAGE SERIES TO ESTIMATE GLACIER MOTION IN THE SOUTHERN PATAGONIA ICE FIELD

    Directory of Open Access Journals (Sweden)

    E. Lannutti

    2016-06-01

    Full Text Available In this work, we assessed the feasibility of using optical flow to obtain the motion estimation of a glacier. In general, former investigations used to detect glacier changes involve solutions that require repeated observations which are many times based on extensive field work. Taking into account glaciers are usually located in geographically complex and hard to access areas, deploying time-lapse imaging sensors, optical flow may provide an efficient solution at good spatial and temporal resolution to describe mass motion. Several studies in computer vision and image processing community have used this method to detect large displacements. Therefore, we carried out a test of the proposed Large Displacement Optical Flow method at the Viedma Glacier, located at South Patagonia Icefield, Argentina. We collected monoscopic terrestrial time-lapse imagery, acquired by a calibrated camera at every 24 hour from April 2014 until April 2015. A filter based on temporal correlation and RGB color discretization between the images was applied to minimize errors related to changes in lighting, shadows, clouds and snow. This selection allowed discarding images that do not follow a sequence of similarity. Our results show a flow field in the direction of the glacier movement with acceleration in the terminus. We analyzed the errors between image pairs, and the matching generally appears to be adequate, although some areas show random gross errors related to the presence of changes in lighting. The proposed technique allowed the determination of glacier motion during one year, providing accurate and reliable motion data for subsequent analysis.

  19. Applying a new computer-aided detection scheme generated imaging marker to predict short-term breast cancer risk

    Science.gov (United States)

    Mirniaharikandehei, Seyedehnafiseh; Hollingsworth, Alan B.; Patel, Bhavika; Heidari, Morteza; Liu, Hong; Zheng, Bin

    2018-05-01

    This study aims to investigate the feasibility of identifying a new quantitative imaging marker based on false-positives generated by a computer-aided detection (CAD) scheme to help predict short-term breast cancer risk. An image dataset including four view mammograms acquired from 1044 women was retrospectively assembled. All mammograms were originally interpreted as negative by radiologists. In the next subsequent mammography screening, 402 women were diagnosed with breast cancer and 642 remained negative. An existing CAD scheme was applied ‘as is’ to process each image. From CAD-generated results, four detection features including the total number of (1) initial detection seeds and (2) the final detected false-positive regions, (3) average and (4) sum of detection scores, were computed from each image. Then, by combining the features computed from two bilateral images of left and right breasts from either craniocaudal or mediolateral oblique view, two logistic regression models were trained and tested using a leave-one-case-out cross-validation method to predict the likelihood of each testing case being positive in the next subsequent screening. The new prediction model yielded the maximum prediction accuracy with an area under a ROC curve of AUC  =  0.65  ±  0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of (2.95, 6.83). The results also showed an increasing trend in the adjusted odds ratio and risk prediction scores (p  breast cancer risk.

  20. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    Science.gov (United States)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-07-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers.

  1. Noninvasive measurement of burn wound depth applying infrared thermal imaging (Conference Presentation)

    Science.gov (United States)

    Jaspers, Mariëlle E.; Maltha, Ilse M.; Klaessens, John H.; Vet, Henrica C.; Verdaasdonk, Rudolf M.; Zuijlen, Paul P.

    2016-02-01

    In burn wounds early discrimination between the different depths plays an important role in the treatment strategy. The remaining vasculature in the wound determines its healing potential. Non-invasive measurement tools that can identify the vascularization are therefore considered to be of high diagnostic importance. Thermography is a non-invasive technique that can accurately measure the temperature distribution over a large skin or tissue area, the temperature is a measure of the perfusion of that area. The aim of this study was to investigate the clinimetric properties (i.e. reliability and validity) of thermography for measuring burn wound depth. In a cross-sectional study with 50 burn wounds of 35 patients, the inter-observer reliability and the validity between thermography and Laser Doppler Imaging were studied. With ROC curve analyses the ΔT cut-off point for different burn wound depths were determined. The inter-observer reliability, expressed by an intra-class correlation coefficient of 0.99, was found to be excellent. In terms of validity, a ΔT cut-off point of 0.96°C (sensitivity 71%; specificity 79%) differentiates between a superficial partial-thickness and deep partial-thickness burn. A ΔT cut-off point of -0.80°C (sensitivity 70%; specificity 74%) could differentiate between a deep partial-thickness and a full-thickness burn wound. This study demonstrates that thermography is a reliable method in the assessment of burn wound depths. In addition, thermography was reasonably able to discriminate among different burn wound depths, indicating its potential use as a diagnostic tool in clinical burn practice.

  2. High-Energy X-Ray Imaging Applied to Nondestructive Characterization of Large Nuclear Waste Drums

    Science.gov (United States)

    Estre, Nicolas; Eck, Daniel; Pettier, Jean-Luc; Payan, Emmanuel; Roure, Christophe; Simon, Eric

    2015-12-01

    As part of its R&D programs on non-destructive testing of nuclear waste drums, CEA is commissioning an irradiation cell named CINPHONIE, at Cadarache. This cell allows high-energy imaging (radiography and tomography) on large volumes (up to 5 m3) and heavy weights (up to 5 tons). A demonstrator has been finalized, based on existing components. The X-ray source is a 9 MeV LINAC which produces Bremsstrahlung X-rays (up to 23 Gy/min at 1 meter in the beam axis). The mechanical bench is digitally controlled on three axes (translation, rotation, elevation) and can handle objects up to 2 t. This bench performs trajectories necessary for acquisition of projections (sinograms) according to different geometries: Translation-Rotation, Fan-Beam and Cone-Beam. Two detection systems both developed by CEA-Leti are available. The first one is a large GADOX scintillating screen ( 800 ×600 mm2) coupled to a low-noise pixelated camera. The second one is a multi-CdTe semiconductor detector, offering measurements up to 5 decades of attenuation (equivalent to 25 cm of lead or 180 cm of standard concrete). At the end of the acquisition, a Filtered Back Projection-based algorithm is performed. Then, a density slice (fan-beam tomography) or a density volume (cone-beam tomography or helical tomography) is produced and used to examine the waste. Characterization of LINAC, associated detectors as well as the full acquisition chain, are presented. Experimental performances on phantoms and real drum are discussed and expected limits on defect detectability are evaluated by simulation. The final system, designed to handle objects up to 5 tons is then presented.

  3. MR of acoustic neuromas

    International Nuclear Information System (INIS)

    Suzuki, Masayuki; Takashima, Tsutomu; Kadoya, Masumi; Takahashi, Shiroh; Miyayama, Shiroh; Taira, Sakae; Kashihara, Kengo; Yamashima, Tetsumori; Itoh, Haruhide

    1989-01-01

    In this report, the relationship of acoustic neuromas to the adjacent cranial nerves is discussed. On T 1 -weighted images, the trigeminal nerve was detected in all 13 cases. Mild to marked compression of these nerves by the tumors was observed in eight cases. The extent of compression did not always correspond to the clinical symptoms. In four cases with a maximum tumor diameter of 2 cm or less, the 7th and 8th cranial nerves were identified. There was no facial palsy in these patients. Two patients with a tumor diameter of more than 2 cm also had no facial palsy. All patients, including those with small tumors, complained of hearing loss and/or tinnitus. While MR imaging has some limitations, it is an effective imaging modality for showing the relationship between tumors and nerves. (author)

  4. Quantifying the visual appearance of sunscreens applied to the skin using indirect computer image colorimetry.

    Science.gov (United States)

    Richer, Vincent; Kharazmi, Pegah; Lee, Tim K; Kalia, Sunil; Lui, Harvey

    2018-03-01

    There is no accepted method to objectively assess the visual appearance of sunscreens on the skin. We present a method for sunscreen application, digital photography, and computer analysis to quantify the appearance of the skin after sunscreen application. Four sunscreen lotions were applied randomly at densities of 0.5, 1.0, 1.5, and 2.0 mg/cm 2 to areas of the back of 29 subjects. Each application site had a matched contralateral control area. High-resolution standardized photographs including a color card were taken after sunscreen application. After color balance correction, CIE L*a*b* color values were extracted from paired sites. Differences in skin appearance attributed to sunscreen were represented by ΔE, which in turn was calculated from the linear Euclidean distance within the L*a*b* color space between the paired sites. Sunscreen visibility as measured by median ΔE varied across different products and application densities and ranged between 1.2 and 12.1. The visibility of sunscreens varied according to product SPF, composition (organic vs inorganic), presence of tint, and baseline b* of skin (P colorimetry represents a potential method to objectively quantify visibility of sunscreen on the skin. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Oscillating acoustic streaming jet

    International Nuclear Information System (INIS)

    Moudjed, Brahim; Botton, Valery; Henry, Daniel; Millet, Severine; Ben Hadid, Hamda; Garandet, Jean-Paul

    2014-01-01

    The present paper provides the first experimental investigation of an oscillating acoustic streaming jet. The observations are performed in the far field of a 2 MHz circular plane ultrasound transducer introduced in a rectangular cavity filled with water. Measurements are made by Particle Image Velocimetry (PIV) in horizontal and vertical planes near the end of the cavity. Oscillations of the jet appear in this zone, for a sufficiently high Reynolds number, as an intermittent phenomenon on an otherwise straight jet fluctuating in intensity. The observed perturbation pattern is similar to that of former theoretical studies. This intermittently oscillatory behavior is the first step to the transition to turbulence. (authors)

  6. Least-square NUFFT methods applied to 2-D and 3-D radially encoded MR image reconstruction.

    Science.gov (United States)

    Song, Jiayu; Liu, Yanhui; Gewalt, Sally L; Cofer, Gary; Johnson, G Allan; Liu, Qing Huo

    2009-04-01

    Radially encoded MRI has gained increasing attention due to its motion insensitivity and reduced artifacts. However, because its samples are collected nonuniformly in the k-space, multidimensional (especially 3-D) radially sampled MRI image reconstruction is challenging. The objective of this paper is to develop a reconstruction technique in high dimensions with on-the-fly kernel calculation. It implements general multidimensional nonuniform fast Fourier transform (NUFFT) algorithms and incorporates them into a k-space image reconstruction framework. The method is then applied to reconstruct from the radially encoded k-space data, although the method is applicable to any non-Cartesian patterns. Performance comparisons are made against the conventional Kaiser-Bessel (KB) gridding method for 2-D and 3-D radially encoded computer-simulated phantoms and physically scanned phantoms. The results show that the NUFFT reconstruction method has better accuracy-efficiency tradeoff than the KB gridding method when the kernel weights are calculated on the fly. It is found that for a particular conventional kernel function, using its corresponding deapodization function as a scaling factor in the NUFFT framework has the potential to improve accuracy. In particular, when a cosine scaling factor is used, the NUFFT method is faster than KB gridding method since a closed-form solution is available and is less computationally expensive than the KB kernel (KB griding requires computation of Bessel functions). The NUFFT method has been successfully applied to 2-D and 3-D in vivo studies on small animals.

  7. Panel acoustic contribution analysis.

    Science.gov (United States)

    Wu, Sean F; Natarajan, Logesh Kumar

    2013-02-01

    Formulations are derived to analyze the relative panel acoustic contributions of a vibrating structure. The essence of this analysis is to correlate the acoustic power flow from each panel to the radiated acoustic pressure at any field point. The acoustic power is obtained by integrating the normal component of the surface acoustic intensity, which is the product of the surface acoustic pressure and normal surface velocity reconstructed by using the Helmholtz equation least squares based nearfield acoustical holography, over each panel. The significance of this methodology is that it enables one to analyze and rank relative acoustic contributions of individual panels of a complex vibrating structure to acoustic radiation anywhere in the field based on a single set of the acoustic pressures measured in the near field. Moreover, this approach is valid for both interior and exterior regions. Examples of using this method to analyze and rank the relative acoustic contributions of a scaled vehicle cabin are demonstrated.

  8. Image intelligence online consulting: A flexible and remote access to strategic information applied to verification of declaration

    International Nuclear Information System (INIS)

    Chassy, A.F. de; Denizot, L.

    2001-01-01

    Commercial satellite imagery is giving International Institutions specialized Information Departments access to a great source of valuable intelligence. High resolution and multiple sensors have also led to a growing complexity of interpretation that calls for a greater need of consulting, verification and training in the field in order to make it eligible as an operational source of verification. Responding to this need, Fleximage is extending its Image Intelligence (IMINT) training program to include a fully operational and flexible online consulting and training program. Image Intelligence (IMINT) Online Program, a new approach to acquiring IMINT expertise, supported by Internet technologies, and managed by a professional team of experts and technical staff. Fleximage has developed a virtual learning environment on the Internet for acquiring IMINT expertise. Called the IMINT Online Program, this dynamic learning environment provides complete flexibility and personalization of the process for acquiring expertise. The IMINT online program includes two services: Online Consulting and Online Training. The Online Consulting service is designed for the technical staff of an organization who are already operational in the field of image intelligence. Online Consulting enables these staff members to acquire pertinent expertise online that can be directly applied to their professional activity, such as IAEA verification tasks. The IMINT virtual Consulting and Training services indicated above are made possible thanks to the latest in Internet-based technologies including: multimedia CD-ROM, Internet technologies, rich media content (Audio, Video and Flash), application sharing, platform Maintenance Tools, secured connections and authentication, knowledge database technologies. IMINT Online Program operates owing to: specialized experts in fields relating to IMINT. These experts carry out the tasks of consultants, coaches, occasional speakers, and course content designers

  9. Applying quantitative benefit-risk analysis to aid regulatory decision making in diagnostic imaging: methods, challenges, and opportunities.

    Science.gov (United States)

    Agapova, Maria; Devine, Emily Beth; Bresnahan, Brian W; Higashi, Mitchell K; Garrison, Louis P

    2014-09-01

    Health agencies making regulatory marketing-authorization decisions use qualitative and quantitative approaches to assess expected benefits and expected risks associated with medical interventions. There is, however, no universal standard approach that regulatory agencies consistently use to conduct benefit-risk assessment (BRA) for pharmaceuticals or medical devices, including for imaging technologies. Economics, health services research, and health outcomes research use quantitative approaches to elicit preferences of stakeholders, identify priorities, and model health conditions and health intervention effects. Challenges to BRA in medical devices are outlined, highlighting additional barriers in radiology. Three quantitative methods--multi-criteria decision analysis, health outcomes modeling and stated-choice survey--are assessed using criteria that are important in balancing benefits and risks of medical devices and imaging technologies. To be useful in regulatory BRA, quantitative methods need to: aggregate multiple benefits and risks, incorporate qualitative considerations, account for uncertainty, and make clear whose preferences/priorities are being used. Each quantitative method performs differently across these criteria and little is known about how BRA estimates and conclusions vary by approach. While no specific quantitative method is likely to be the strongest in all of the important areas, quantitative methods may have a place in BRA of medical devices and radiology. Quantitative BRA approaches have been more widely applied in medicines, with fewer BRAs in devices. Despite substantial differences in characteristics of pharmaceuticals and devices, BRA methods may be as applicable to medical devices and imaging technologies as they are to pharmaceuticals. Further research to guide the development and selection of quantitative BRA methods for medical devices and imaging technologies is needed. Copyright © 2014 AUR. Published by Elsevier Inc. All rights

  10. Acoustic Imaging of Selected Areas of Gdansk Bay with the Aid of Parametric Echosounder and Side-Scan Sonar

    Directory of Open Access Journals (Sweden)

    Grelowska Grażyna

    2017-12-01

    Full Text Available The article presents and analyses the data recorded during sounding of the Gdansk Bay seabed with the aid of a parametric echosounder and a side-scan sonar. The accuracy of seabed structure examination, as a condition for obtaining valuable results, requires correct configuration of echolocation devices and proper calibration of peripheral devices, such as the survey unit geographical position sensor - GPS, the navigation unit, the MRU-Z sensor of pitch, roll and heave, and the sound velocity meter, which deliver the data to the bathymetric measurement system. Parametric seabed profilers deliver two types of data: the envelope, and the detailed echo signal without processing. The envelope is used for data visualisation in the form of online echograms, while the echo signal is stored for further analyses, to be performed using dedicated software or, after relevant conversion, in arbitrary programming environment1. The presented data analysis is illustrated by selected sample images recorded by the parametric echosounder and the side-scan sonar during Gdansk Bay sounding.

  11. The acoustics of snoring.

    Science.gov (United States)

    Pevernagie, Dirk; Aarts, Ronald M; De Meyer, Micheline

    2010-04-01

    Snoring is a prevalent disorder affecting 20-40% of the general population. The mechanism of snoring is vibration of anatomical structures in the pharyngeal airway. Flutter of the soft palate accounts for the harsh aspect of the snoring sound. Natural or drug-induced sleep is required for its appearance. Snoring is subject to many influences such as body position, sleep stage, route of breathing and the presence or absence of sleep-disordered breathing. Its presentation may be variable within or between nights. While snoring is generally perceived as a social nuisance, rating of its noisiness is subjective and, therefore, inconsistent. Objective assessment of snoring is important to evaluate the effect of treatment interventions. Moreover, snoring carries information relating to the site and degree of obstruction of the upper airway. If evidence for monolevel snoring at the site of the soft palate is provided, the patient may benefit from palatal surgery. These considerations have inspired researchers to scrutinize the acoustic characteristics of snoring events. Similarly to speech, snoring is produced in the vocal tract. Because of this analogy, existing techniques for speech analysis have been applied to evaluate snoring sounds. It appears that the pitch of the snoring sound is in the low-frequency range (noise-like', and has scattered energy content in the higher spectral sub-bands (>500 Hz). To evaluate acoustic properties of snoring, sleep nasendoscopy is often performed. Recent evidence suggests that the acoustic quality of snoring is markedly different in drug-induced sleep as compared with natural sleep. Most often, palatal surgery alters sound characteristics of snoring, but is no cure for this disorder. It is uncertain whether the perceived improvement after palatal surgery, as judged by the bed partner, is due to an altered sound spectrum. Whether some acoustic aspects of snoring, such as changes in pitch, have predictive value for the presence of

  12. Acoustic emission from polycrystalline graphites

    International Nuclear Information System (INIS)

    Ioka, I.; Yoda, S.; Oku, T.; Miyamoto, Y.

    1987-01-01

    Acoustic emission was monitored from polycrystalline graphites with different microstructure (pore size and pore volume) subjected to compressive loading. The graphites used in this study comprised five brands, that is, PGX, ISEM-1, IG-11, IG-15, and ISO-88. A root mean square (RMS) voltage and event counts of acoustic emission for graphites were measured during compressive loading. The acoustic emission was measured using a computed-based data acquisition and analysis system. The graphites were first deformed up to 80 % of the average fracture stress, then unloaded and reloaded again until the fracture occured. During the first loading, the change in RMS voltage for acoustic emission was detected from the initial stage. During the unloading, the RMS voltage became zero level as soon as the applied stress was released and then gradually rose to a peak and declined. The behavior indicated that the reversed plastic deformation occured in graphites. During the second loading, the RMS voltage gently increased until the applied stress exceeded the maximum stress of the first loading; there is no Kaiser effect in the graphites. A bicrystal model could give a reasonable explanation of this results. The empirical equation between the ratio of σ AE to σ f and σ f was obtained. It is considered that the detection of microfracture by the acoustic emission technique is effective in macrofracture prediction of polycrystalline graphites. (author)

  13. Acoustic radiation force impulse-imaging and transient elastography for non-invasive assessment of liver fibrosis and steatosis in NAFLD

    International Nuclear Information System (INIS)

    Friedrich-Rust, Mireen; Romen, Daniela; Vermehren, Johannes; Kriener, Susanne; Sadet, Dilek; Herrmann, Eva; Zeuzem, Stefan; Bojunga, Joerg

    2012-01-01

    Background: Transient elastography (TE) and acoustic radiation force impulse (ARFI)-imaging have shown promising results for the staging of liver fibrosis. Aim: The aim of the present study was to compare ARFI of the left and right liver lobe with TE using the standard and obese probes for the diagnosis of liver fibrosis in NAFL/NASH. In addition, liver steatosis is evaluated using the novel controlled attenuation parameter (CAP). Methods: Sixty-one patients with NAFLD/NASH were included in the study. All patients received TE with both probes, ARFI of both liver lobes and CAP. The results were compared with liver histology. Results: 57 patients were included in the final analysis. The diagnostic accuracy for TE measurements with the M-and XL-probe and for ARFI of the right and left liver lobe was 0.73, 0.84, 0.71 and 0.60 for the diagnosis of severe fibrosis, and 0.93, 0.93, 0.74 and 0.90 for the diagnosis of cirrhosis, respectively. No significant difference of results was observed between TE and ARFI in the subgroup of patients with reliable TE-measurement when taking into account the best results of both methods. However, while a significant correlation could be found for TE with histological liver fibrosis, the correlation of ARFI with liver fibrosis was not statistically significant. A significant correlation was found for CAP with histological steatosis (r = 0.49, p < 0.001). Conclusions: No significant difference in diagnostic accuracy for the non-invasive assessment of liver fibrosis was found for transient elastography and ARFI. Nevertheless TE significantly correlated with liver fibrosis while ARFI did not. CAP enables the non-invasive assessment of steatosis.

  14. Acoustics and Hearing

    CERN Document Server

    Damaske, Peter

    2008-01-01

    When one listens to music at home, one would like to have an acoustic impression close to that of being in the concert hall. Until recently this meant elaborate multi-channelled sound systems with 5 or more speakers. But head-related stereophony achieves the surround-sound effect in living rooms with only two loudspeakers. By virtue of their slight directivity as well as an electronic filter the limitations previously common to two-speaker systems can be overcome and this holds for any arbitrary two-channel recording. The book also investigates the question of how a wide and diffuse sound image can arise in concert halls and shows that the quality of concert halls decisively depends on diffuse sound images arising in the onset of reverberation. For this purpose a strong onset of reverberation is modified in an anechoic chamber by electroacoustic means. Acoustics and Hearing proposes ideas concerning signal processing in the auditory system that explain the measured results and the resultant sound effects plea...

  15. Acoustic transducer

    Science.gov (United States)

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  16. Acoustic cryocooler

    International Nuclear Information System (INIS)

    Swift, G.W.; Martin, R.A.; Radebaugh, R.

    1990-01-01

    This patent describes an acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effect to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15--60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintain a cooling load of 5 W at 80 K

  17. Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

    International Nuclear Information System (INIS)

    Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

    2017-01-01

    Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers. - Highlights: • Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. • Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. • However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. • Optical tweezers can trap, move and positioned micron size particles with subnanometer accuracy in three dimensions. • One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. • Acoustical tweezers overcome this limitation since the force scales as the field intensity divided by its propagation speed. • However, the feasibility of single beam acoustical tweezers was demonstrated only recently. • We propose a review of the strong similarities but also the specificities of acoustical

  18. Phase Transition Mapping by Means of Neutron Imaging in SOFC Anode Supports During Reduction Under Applied Stress

    DEFF Research Database (Denmark)

    Makowska, Malgorzata; Strobl, M.; Lauridsen, E. M.

    2015-01-01

    Mechanical and electrochemical performance of layers composed of Ni-YSZ cermet in solid oxide fuel and electrolysis cells (SOC) depends on their microstructure and initial internal stresses. After sintering, the manufacturing conditions, i.e. temperature, atmosphere and loads, can influence...... the microstructure and in particular the internal stresses in the Ni-YSZ layer and thereby the cell performance. Spatially resolved observation of the phase transition during reduction can provide information on how parameters like temperature and external load influence the reaction progress. This information...... is crucial for optimization of the SOC performance. In this work the measurements with energy resolved neutron imaging of the phase transition during the NiOYSZ reduction performed at different temperatures with and without applied load, are presented. The results indicate a link between reduction rate...

  19. Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) with Raman Imaging Applied to Lunar Meteorites.

    Science.gov (United States)

    Smith, Joseph P; Smith, Frank C; Booksh, Karl S

    2018-03-01

    Lunar meteorites provide a more random sampling of the surface of the Moon than do the returned lunar samples, and they provide valuable information to help estimate the chemical composition of the lunar crust, the lunar mantle, and the bulk Moon. As of July 2014, ∼96 lunar meteorites had been documented and ten of these are unbrecciated mare basalts. Using Raman imaging with multivariate curve resolution-alternating least squares (MCR-ALS), we investigated portions of polished thin sections of paired, unbrecciated, mare-basalt lunar meteorites that had been collected from the LaPaz Icefield (LAP) of Antarctica-LAP 02205 and LAP 04841. Polarized light microscopy displays that both meteorites are heterogeneous and consist of polydispersed sized and shaped particles of varying chemical composition. For two distinct probed areas within each meteorite, the individual chemical species and associated chemical maps were elucidated using MCR-ALS applied to Raman hyperspectral images. For LAP 02205, spatially and spectrally resolved clinopyroxene, ilmenite, substrate-adhesive epoxy, and diamond polish were observed within the probed areas. Similarly, for LAP 04841, spatially resolved chemical images with corresponding resolved Raman spectra of clinopyroxene, troilite, a high-temperature polymorph of anorthite, substrate-adhesive epoxy, and diamond polish were generated. In both LAP 02205 and LAP 04841, substrate-adhesive epoxy and diamond polish were more readily observed within fractures/veinlet features. Spectrally diverse clinopyroxenes were resolved in LAP 04841. Factors that allow these resolved clinopyroxenes to be differentiated include crystal orientation, spatially distinct chemical zoning of pyroxene crystals, and/or chemical and molecular composition. The minerals identified using this analytical methodology-clinopyroxene, anorthite, ilmenite, and troilite-are consistent with the results of previous studies of the two meteorites using electron microprobe

  20. A new definition for acoustic dose

    International Nuclear Information System (INIS)

    Duck, F A

    2011-01-01

    This paper discusses a recent proposal for definitions of acoustic dose and acoustic dose-rate. Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Its time-derivative, acoustic dose-rate, Q m , in W kg -1 is central to the prediction of both rate of temperature rise and radiation force. These quantities have spatial and temporal dependency, depending on the local field parameters (acoustic pressure, particle velocity, intensity) and local material properties (absorption coefficient, α a , and mass density, ρ 0 ). Spatial and/or temporal averaging can be applied where appropriate. For plane-wave monochromatic conditions in a homogeneous medium, Q m =2α a I/ρ 0 , (I is the time-averaged intensity), a simple expression which may also incorporate frequency dependencies of energy deposition. Acoustic dose and acoustic does-rate are exact analogues for Specific Absorption and Specific Absorption Rate (SAR), quantities central to radiofrequency (RF) and microwave dosimetry. Acoustic dosimetry in the presence of tissue/gas interfaces remains a considerable challenge.

  1. Use of acoustic vortices in acoustic levitation

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Santillan, Arturo Orozco; Juhl, Peter Møller

    2009-01-01

    Acoustic fields are known to exert forces on the surfaces of objects. These forces are noticeable if the sound pressure is sufficiently high. Two phenomena where acoustic forces are relevant are: i) acoustic levitation, where strong standing waves can hold small objects at certain positions......, counterbalancing their weight, and ii) acoustic vortices, spinning sound fields that can impinge angular momentum and cause rotation of objects. In this contribution, both force-creating sound fields are studied by means of numerical simulations. The Boundary Element Method is employed to this end. The simulation...... of acoustical vortices uses an efficient numerical implementation based on the superposition of two orthogonal sound fields with a delay of 90° between them. It is shown that acoustic levitation and the use of acoustic vortices can be combined to manipulate objects in an efficient and controlled manner without...

  2. Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator

    KAUST Repository

    Elayouch, A.

    2017-01-05

    We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degrees-bent channel. This kind of acoustic metamaterial can, therefore, give rise to acoustic functions like controlling the wavefront, which may lead to very promising applications in acoustic cloacking or imaging.

  3. Transmission and signal loss in mask designs for a dual neutron and gamma imager applied to mobile standoff detection

    International Nuclear Information System (INIS)

    Ayaz-Maierhafer, Birsen; Hayward, Jason P.; Ziock, Klaus P.; Blackston, Matthew A.; Fabris, Lorenzo

    2013-01-01

    In order to design a next-generation, dual neutron and gamma imager for mobile standoff detection which uses coded aperture imaging as its primary detection modality, the following design parameters have been investigated for gamma and neutron radiation incident upon a hybrid, coded mask: (1) transmission through mask elements for various mask materials and thicknesses; and (2) signal attenuation in the mask versus angle of incidence. Each of these parameters directly affects detection significance, as quantified by the signal-to-noise ratio. The hybrid mask consists of two or three layers: organic material for fast neutron attenuation and scattering, Cd for slow neutron absorption (if applied), and one of three of the following photon or photon and slow neutron attenuating materials—Linotype alloy, CLYC, or CZT. In the MCNP model, a line source of gamma rays (100–2500 keV), fast neutrons (1000–10,000 keV) or thermal neutrons was positioned above the hybrid mask. The radiation penetrating the mask was simply tallied at the surface of an ideal detector, which was located below the surface of the last mask layer. The transmission was calculated as the ratio of the particles transmitted through the fixed aperture to the particles passing through the closed mask. In order to determine the performance of the mask considering relative motion between the source and detector, simulations were used to calculate the signal attenuation for incident radiation angles of 0–50°. The results showed that a hybrid mask can be designed to sufficiently reduce both transmission through the mask and signal loss at large angles of incidence, considering both gamma ray and fast neutron radiations. With properly selected material thicknesses, the signal loss of a hybrid mask, which is necessarily thicker than the mask required for either single mode imaging, is not a setback to the system's detection significance

  4. Interior acoustic cloak

    OpenAIRE

    Wael Akl; A. Baz

    2014-01-01

    Acoustic cloaks have traditionally been intended to externally surround critical objects to render these objects acoustically invisible. However, in this paper, the emphasis is placed on investigating the application of the acoustic cloaks to the interior walls of acoustic cavities in an attempt to minimize the noise levels inside these cavities. In this manner, the acoustic cloaks can serve as a viable and efficient alternative to the conventional passive noise attenuation treatments which a...

  5. Thin-film sparse boundary array design for passive acoustic mapping during ultrasound therapy.

    Science.gov (United States)

    Coviello, Christian M; Kozick, Richard J; Hurrell, Andrew; Smith, Penny Probert; Coussios, Constantin-C

    2012-10-01

    A new 2-D hydrophone array for ultrasound therapy monitoring is presented, along with a novel algorithm for passive acoustic mapping using a sparse weighted aperture. The array is constructed using existing polyvinylidene fluoride (PVDF) ultrasound sensor technology, and is utilized for its broadband characteristics and its high receive sensitivity. For most 2-D arrays, high-resolution imagery is desired, which requires a large aperture at the cost of a large number of elements. The proposed array's geometry is sparse, with elements only on the boundary of the rectangular aperture. The missing information from the interior is filled in using linear imaging techniques. After receiving acoustic emissions during ultrasound therapy, this algorithm applies an apodization to the sparse aperture to limit side lobes and then reconstructs acoustic activity with high spatiotemporal resolution. Experiments show verification of the theoretical point spread function, and cavitation maps in agar phantoms correspond closely to predicted areas, showing the validity of the array and methodology.

  6. High throughput imaging cytometer with acoustic focussing† †Electronic supplementary information (ESI) available: High throughput imaging cytometer with acoustic focussing. See DOI: 10.1039/c5ra19497k Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file.

    Science.gov (United States)

    Zmijan, Robert; Jonnalagadda, Umesh S.; Carugo, Dario; Kochi, Yu; Lemm, Elizabeth; Packham, Graham; Hill, Martyn

    2015-01-01

    We demonstrate an imaging flow cytometer that uses acoustic levitation to assemble cells and other particles into a sheet structure. This technique enables a high resolution, low noise CMOS camera to capture images of thousands of cells with each frame. While ultrasonic focussing has previously been demonstrated for 1D cytometry systems, extending the technology to a planar, much higher throughput format and integrating imaging is non-trivial, and represents a significant jump forward in capability, leading to diagnostic possibilities not achievable with current systems. A galvo mirror is used to track the images of the moving cells permitting exposure times of 10 ms at frame rates of 50 fps with motion blur of only a few pixels. At 80 fps, we demonstrate a throughput of 208 000 beads per second. We investigate the factors affecting motion blur and throughput, and demonstrate the system with fluorescent beads, leukaemia cells and a chondrocyte cell line. Cells require more time to reach the acoustic focus than beads, resulting in lower throughputs; however a longer device would remove this constraint. PMID:29456838

  7. Testing the Feasibility of Using PERM to Apply Scattering-Angle Filtering in the Image-Domain for FWI Applications

    KAUST Repository

    Alzahrani, Hani Ataiq

    2014-09-01

    ABSTRACT Testing the Feasibility of Using PERM to Apply Scattering-Angle Filtering in the Image-Domain for FWI Applications Hani Ataiq Alzahrani Full Waveform Inversion (FWI) is a non-linear optimization problem aimed to estimating subsurface parameters by minimizing the mis t between modeled and recorded seismic data using gradient descent methods, which are the only practical choice because of the size of the problem. Due to the high non-linearity of the problem, gradient methods will converge to a local minimum if the starting model is not close to the true one. The accuracy of the long-wavelength components of the initial model controls the level of non-linearity of the inversion. In order for FWI to converge to the global minimum, we have to obtain the long wavelength components of the model before inverting for the short wavelengths. Ultra-low temporal frequencies are sensitive to the smooth (long wavelength) part of the model, and can be utilized by waveform inversion to resolve that part. Un- fortunately, frequencies in this range are normally missing in eld data due to data- acquisition limitations. The lack of low frequencies can be compensated for by uti- lizing wide-aperture data, as they include arrivals that are especially sensitive to the long wavelength components of the model. The higher the scattering angle of a 5 recorded event, the higher the model wavelength it can resolve. Based on this prop- erty, a scattering-angle ltering algorithm is proposed to start the inversion process with events corresponding to the highest scattering angle available in the data, and then include lower scattering angles progressively. The large scattering angles will resolve the smooth part of the model and reduce the non-linearity of the problem, then the lower ones will enhance the resolution of the model. Recorded data is rst migrated using Pre-stack Exploding Re ector Migration (PERM), then the resulting pre-stack image is transformed into angle gathers to which

  8. Supersonic acoustic intensity with statistically optimized near-field acoustic holography

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2011-01-01

    The concept of supersonic acoustic intensity was introduced some years ago for estimating the fraction of the flow of energy radiated by a source that propagates to the far field. It differs from the usual (active) intensity by excluding the near-field energy resulting from evanescent waves...... to the information provided by the near-field acoustic holography technique. This study proposes a version of the supersonic acoustic intensity applied to statistically optimized near-field acoustic holography (SONAH). The theory, numerical results and an experimental study are presented. The possibility of using...

  9. Detection method of internal leakage from valve using acoustic method

    International Nuclear Information System (INIS)

    Kumagai, Horomichi

    1990-01-01

    The purpose of this study is to estimate the availability of acoustic method for detecting the internal leakage of valves at power plants. Experiments have been carried out on the characteristics of acoustic noise caused by the leak simulated flow. From the experimental results, the mechanism of the acoustic noisegenerated from flow, the relation between acoustic intensity and leak flow velocity, and the characteristics of the acoustic frequency spectrum were clarified. The acoustic method was applied to valves at site, and the background noises were measured in abnormal plant conditions. When the background level is higher than the acoustic signal, the difference between the background noise frequency spectrum and the acoustic signal spectrum provide a very useful leak detection method. (author)

  10. Software-based acoustical measurements

    CERN Document Server

    Miyara, Federico

    2017-01-01

    This textbook provides a detailed introduction to the use of software in combination with simple and economical hardware (a sound level meter with calibrated AC output and a digital recording system) to obtain sophisticated measurements usually requiring expensive equipment. It emphasizes the use of free, open source, and multiplatform software. Many commercial acoustical measurement systems use software algorithms as an integral component; however the methods are not disclosed. This book enables the reader to develop useful algorithms and provides insight into the use of digital audio editing tools to document features in the signal. Topics covered include acoustical measurement principles, in-depth critical study of uncertainty applied to acoustical measurements, digital signal processing from the basics, and metrologically-oriented spectral and statistical analysis of signals. The student will gain a deep understanding of the use of software for measurement purposes; the ability to implement software-based...

  11. Phonemes as images : An experimental inquiry into shape-sound symbolism applied to the distinctive features of French

    OpenAIRE

    Nobile , Luca

    2015-01-01

    International audience; This paper attempts to improve the understanding of shape-sound symbolism by isolating the phonological features of the pseudo-words used in the experiments and the graphic features of the figures matched with them. In a first section, it analyses the classic maluma-takete effect from both an articulatory and acoustical point of view, showing that it is determined by several phonological features operating simultaneously. In a second section, two new experiments are pr...

  12. Acoustic levitation in the presence of gravity

    Science.gov (United States)

    Collas, P.; Barmatz, M.; Shipley, C.

    1989-01-01

    The method of Gor'kov (1961) has been applied to derive general expressions for the total potential and force on a small spherical object in a resonant chamber in the presence of both acoustic and gravitational force fields. The levitation position is also determined in rectangular resonators for the simultaneous excitation of up to three acoustic modes, and the results are applied to the triple-axis acoustic levitator. The analysis is applied to rectangular, spherical, and cylindrical single-mode levitators that are arbitrarily oriented relative to the gravitational force field. Criteria are determined for isotropic force fields in rectangular and cylindrical resonators. It is demonstrated that an object will be situated within a volume of possible levitation positions at a point determined by the relative strength of the acoustic and gravitational fields and the orientation of the chamber relative to gravity.

  13. Springer Handbook of Acoustics

    CERN Document Server

    Rossing, Thomas D

    2007-01-01

    Acoustics, the science of sound, has developed into a broad interdisciplinary field encompassing the academic disciplines of physics, engineering, psychology, speech, audiology, music, architecture, physiology, neuroscience, and others. The Springer Handbook of Acoustics is an unparalleled modern handbook reflecting this richly interdisciplinary nature edited by one of the acknowledged masters in the field, Thomas Rossing. Researchers and students benefit from the comprehensive contents spanning: animal acoustics including infrasound and ultrasound, environmental noise control, music and human speech and singing, physiological and psychological acoustics, architectural acoustics, physical and engineering acoustics, signal processing, medical acoustics, and ocean acoustics. This handbook reviews the most important areas of acoustics, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest rese...

  14. Responsive acoustic surfaces

    DEFF Research Database (Denmark)

    Peters, Brady; Tamke, Martin; Nielsen, Stig Anton

    2011-01-01

    Acoustic performance is defined by the parameter of reverberation time; however, this does not capture the acoustic experience in some types of open plan spaces. As many working and learning activities now take place in open plan spaces, it is important to be able to understand and design...... for the acoustic conditions of these spaces. This paper describes an experimental research project that studied the design processes necessary to design for sound. A responsive acoustic surface was designed, fabricated and tested. This acoustic surface was designed to create specific sonic effects. The design...... was simulated using custom integrated acoustic software and also using Odeon acoustic analysis software. The research demonstrates a method for designing space- and sound-defining surfaces, defines the concept of acoustic subspace, and suggests some new parameters for defining acoustic subspaces....

  15. International Conference on Acoustics and Vibration

    CERN Document Server

    Chaari, Fakher; Walha, Lasaad; Abdennadher, Moez; Abbes, Mohamed; Haddar, Mohamed

    2017-01-01

    The book provides readers with a snapshot of recent research and industrial trends in field of industrial acoustics and vibration. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at International Conference on Acoustics and Vibration (ICAV2016), which was organized by the Tunisian Association of Industrial Acoustics and Vibration (ATAVI) and held March 21-23, in Hammamet, Tunisia. The contributions, mainly written by north African authors, covers advances in both theory and practice in a variety of subfields, such as: smart materials and structures; fluid-structure interaction; structural acoustics as well as computational vibro-acoustics and numerical methods. Further topics include: engines control, noise identification, robust design, flow-induced vibration and many others.This book provides a valuable resource for both academics and professionals dealing with diverse issues in applied mechanics. By combining advanced theori...

  16. Method and apparatus for generating acoustic waves

    International Nuclear Information System (INIS)

    Rao, G.V.; Gopal, R.

    1982-01-01

    A portable source of acoustic waves comprises a sample of iron-nickel alloy including an austenite phase cooled to become martensite, and a wave guide to transmit the acoustic waves. The source is applied to the pressure boundary region of a pressurized water reactor to simulate an actual metal flaw and test the calibration of the monitoring and surveillance system. With at most 29.7% nickel in the sample, the source provides acoustic emission due to ductile deformation, and with at least 30% nickel the acoustic emission is characteristic of a brittle deformation. Thus, the monitoring and surveillance system can be tested in either or both situations. In the prior art, synthetic waveform signals were used for such calibration but found not suitable for on-line simulation of the surveillance system. This invention provides an improved system in that it generates true acoustic signals. (author)

  17. Surface acoustic waves voltage controlled directional coupler

    Science.gov (United States)

    Golan, G.; Griffel, G.; Yanilov, E.; Ruschin, S.; Seidman, A.; Croitoru, N.

    1988-10-01

    An important condition for the development of surface wave integrated-acoustic devices is the ability to guide and control the propagation of the acoustic energy. This can be implemented by deposition of metallic "loading" channels on an anisotropic piezoelectric substrate. Deposition of such two parallel channels causes an effective coupling of acoustic energy from one channel to the other. A basic requirement for this coupling effect is the existence of the two basic modes: a symmetrical and a nonsymmetrical one. A mode map that shows the number of sustained modes as a function of the device parameters (i.e., channel width; distance between channels; material velocity; and acoustical exciting frequency) is presented. This kind of map can help significantly in the design process of such a device. In this paper we devise an advanced acoustical "Y" coupler with the ability to control its effective coupling by an externally applied voltage, thereby causing modulation of the output intensities of the signals.

  18. On architectural acoustic design using computer simulation

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due; Kirkegaard, Poul Henning

    2004-01-01

    properties prior to the actual construction of a building. With the right tools applied, acoustic design can become an integral part of the architectural design process. The aim of this paper is to investigate the field of application that an acoustic simulation programme can have during an architectural...... acoustic design process. The emphasis is put on the first three out of five phases in the working process of the architect and a case study is carried out in which each phase is represented by typical results ? as exemplified with reference to the design of Bagsværd Church by Jørn Utzon. The paper...... discusses the advantages and disadvantages of the programme in each phase compared to the works of architects not using acoustic simulation programmes. The conclusion of the paper is that the application of acoustic simulation programs is most beneficial in the last of three phases but an application...

  19. Quantitative evaluation of automated skull-stripping methods applied to contemporary and legacy images: effects of diagnosis, bias correction, and slice location

    DEFF Research Database (Denmark)

    Fennema-Notestine, Christine; Ozyurt, I Burak; Clark, Camellia P

    2006-01-01

    Extractor (BSE, Sandor and Leahy [1997] IEEE Trans Med Imag 16:41-54; Shattuck et al. [2001] Neuroimage 13:856-876) to manually stripped images. The methods were applied to uncorrected and bias-corrected datasets; Legacy and Contemporary T1-weighted image sets; and four diagnostic groups (depressed...... distances, and an Expectation-Maximization algorithm. Methods tended to perform better on contemporary datasets; bias correction did not significantly improve method performance. Mesial sections were most difficult for all methods. Although AD image sets were most difficult to strip, HWA and BSE were more...

  20. Influence of different frequencies and insertion depths on the diagnostic accuracy of liver elastography by acoustic radiation force impulse imaging (ARFI)

    Energy Technology Data Exchange (ETDEWEB)

    Potthoff, Andrej, E-mail: potthoff.andrej@mh-hannover.de [Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover (Germany); Attia, Dina; Pischke, Sven; Kirschner, Janina; Mederacke, Ingmar; Wedemeyer, Heiner; Manns, Michael P.; Gebel, Michael J.; Rifai, Kinan [Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover (Germany)

    2013-08-15

    Background: Acoustic Radiation Force Impulse Imaging (ARFI) is an innovative elastography for staging of liver fibrosis. We evaluated the diagnostic accuracy of different probes to perform ARFI at different insertion depths. Methods: In a prospective study, 89 chronic HCV infected patients underwent ARFI elastography using both available probes (c-ARFI: C4-1-MHz; l-ARFI: L9-4 MHz) in comparison to Fibroscan{sup ®}. Variability of ARFI elastography at different insertion depths was systematically evaluated in 39 patients (44%). According to Fibroscan{sup ®} elastography, 32 patients (36%) presented with liver cirrhosis, 23 patients (26%) had significant fibrosis and 34 patients (38%) had no significant fibrosis. Results: Mean propagation velocity with c-ARFI was 1.70 ± 0.67 m/s and 1.91 ± 0.87 m/s with l-ARFI. Results of both probes were correlated to each other (p < 0.001; r = 0.70) and to Fibroscan{sup ®} (p < 0.001, r = 0.82 and 0.84, respectively). In patients with significant fibrosis or with cirrhosis, mean values by l-ARFI were significantly higher than by c-ARFI (p < 0.001). For detection of liver cirrhosis, AUROC was 0.97 for c-ARFI (cut-off level 1.72 m/s) and 0.90 for l-ARFI (cut-off 2.04 m/s). Correlation coefficients of c-ARFI with Fibroscan{sup ®} were highest at an insertion depth of 5–6 cm (r = 0.882 and 0.864, respectively, p < 0.001) and at 3–4 cm for l-ARFI (r = 0.850 and 0.838, respectively, p < 0.001). Conclusions: ARFI elastography with the linear and with the convex probes showed comparable validity and accuracy in the estimation of liver stiffness. The linear probe gave higher ARFI values. The most accurate insertion depth was 5–6 cm for c-ARFI and 3–4 cm for l-ARFI indicating that measurements should not be performed close to the liver capsule.

  1. Airy acoustical-sheet spinner tweezers

    Science.gov (United States)

    Mitri, F. G.

    2016-09-01

    The Airy acoustical beam exhibits parabolic propagation and spatial acceleration, meaning that the propagation bending angle continuously increases before the beam trajectory reaches a critical angle where it decays after a propagation distance, without applying any external bending force. As such, it is of particular importance to investigate its properties from the standpoint of acoustical radiation force, spin torque, and particle dynamics theories, in the development of novel particle sorting techniques and acoustically mediated clearing systems. This work investigates these effects on a two-dimensional (2D) circular absorptive structure placed in the field of a nonparaxial Airy "acoustical-sheet" (i.e., finite beam in 2D), for potential applications in surface acoustic waves and acousto-fluidics. Based on the characteristics of the acoustic field, the beam is capable of manipulating the circular cylindrical fluid cross-section and guides it along a transverse or parabolic trajectory. This feature of Airy acoustical beams could lead to a unique characteristic in single-beam acoustical tweezers related to acoustical sieving, filtering, and removal of particles and cells from a section of a small channel. The analysis developed here is based on the description of the nonparaxial Airy beam using the angular spectrum decomposition of plane waves in close association with the partial-wave series expansion method in cylindrical coordinates. The numerical results demonstrate the ability of the nonparaxial Airy acoustical-sheet beam to pull, propel, or accelerate a particle along a parabolic trajectory, in addition to particle confinement in the transverse direction of wave propagation. Negative or positive radiation force and spin torque causing rotation in the clockwise or the anticlockwise direction can occur depending on the nondimensional parameter ka (where k is the wavenumber and a is the radius) and the location of the cylinder in the beam. Applications in

  2. Ex vivo and in vitro synchrotron-based micro-imaging of biocompatible materials applied in dental surgery

    Science.gov (United States)

    Rack, A.; Stiller, M.; Nelson, K.; Knabe, C.; Rack, T.; Zabler, S.; Dalügge, O.; Riesemeier, H.; Cecilia, A.; Goebbels, J.

    2010-09-01

    Biocompatible materials such as porous bioactive calcium phosphate ceramics or titanium are regularly applied in dental surgery: ceramics are used to support the local bone regeneration in a given defect, afterwards titanium implants replace lost teeth. The current gold standard for bone reconstruction in implant dentistry is the use of autogenous bone grafts. But the concept of guided bone regeneration (GBR) has become a predictable and well documented surgical approach using biomaterials (bioactive calcium phosphate ceramics) which qualify as bone substitutes for this kind of application as well. We applied high resolution synchrotron microtomography and subsequent 3d image analysis in order to investigate bone formation and degradation of the bone substitute material in a three-dimensional manner, extending the knowledge beyond the limits of classical histology. Following the bone regeneration, titanium-based implants to replace lost teeth call for high mechanical precision, especially when two-piece concepts are used in order to guaranty leak tightness. Here, synchrotron-based radiography in comparison with classical laboratory radiography yields high spatial resolution in combination with high contrast even when exploiting micro-sized features in these kind of highly attenuating objects. Therefore, we could study micro-gap formation at interfaces in two-piece dental implants with the specimen under different mechanical load. We could prove the existence of micro-gaps for implants with conical connections as well as to study the micromechanical behavior of the mating zone of conical implants during loading. The micro-gap is a potential issue of failure, i. e. bacterial leakage which can induce an inflammatory process.

  3. Acoustic source for generating an acoustic beam

    Science.gov (United States)

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  4. Acoustic grating fringe projector for high-speed and high-precision three-dimensional shape measurements

    International Nuclear Information System (INIS)

    Yin Xuebing; Zhao Huijie; Zeng Junyu; Qu Yufu

    2007-01-01

    A new acoustic grating fringe projector (AGFP) was developed for high-speed and high-precision 3D measurement. A new acoustic grating fringe projection theory is also proposed to describe the optical system. The AGFP instrument can adjust the spatial phase and period of fringes with unprecedented speed and accuracy. Using rf power proportional-integral-derivative (PID) control and CCD synchronous control, we obtain fringes with fine sinusoidal characteristics and realize high-speed acquisition of image data. Using the device, we obtained a precise phase map for a 3D profile. In addition, the AGFP can work in running fringe mode, which could be applied in other measurement fields

  5. Agorá Acoustics - Effects of arcades on the acoustics of public squares

    DEFF Research Database (Denmark)

    Paini, Dario; Gade, Anders Christian; Rindel, Jens Holger

    2005-01-01

    This paper is part of a PhD work, dealing with the acoustics of the public squares (‘Agorá Acoustics’), especially when music (amplified or not) is played. Consequently, our approach will be to evaluate public squares using the same set of acoustics concepts for subjective evaluation and objective...... measurements as applied for concert halls and theatres. In this paper the acoustical effects of arcades will be studied, in terms of reverberation (EDT and T30), clarity (C80), intelligibility (STI) and other acoustical parameters. For this purpose, also the theory of coupled rooms is applied and compared...... with results. An acoustic modelling program, ODEON 7.0, was used for this investigation. Three different sizes of public squares were considered. In order to evaluate the ‘real’ effects of the arcades on the open square, models of all three squares were designed both with and without arcades. The sound source...

  6. Pattern recognition methods for acoustic emission analysis

    International Nuclear Information System (INIS)

    Doctor, P.G.; Harrington, T.P.; Hutton, P.H.

    1979-07-01

    Models have been developed that relate the rate of acoustic emissions to structural integrity. The implementation of these techniques in the field has been hindered by the noisy environment in which the data must be taken. Acoustic emissions from noncritical sources are recorded in addition to those produced by critical sources, such as flaws. A technique is discussed for prescreening acoustic events and filtering out those that are produced by noncritical sources. The methodology that was investigated is pattern recognition. Three different pattern recognition techniques were applied to a data set that consisted of acoustic emissions caused by crack growth and acoustic signals caused by extraneous noise sources. Examination of the acoustic emission data presented has uncovered several features of the data that can provide a reasonable filter. Two of the most valuable features are the frequency of maximum response and the autocorrelation coefficient at Lag 13. When these two features and several others were combined with a least squares decision algorithm, 90% of the acoustic emissions in the data set were correctly classified. It appears possible to design filters that eliminate extraneous noise sources from flaw-growth acoustic emissions using pattern recognition techniques

  7. Acoustic emission linear pulse holography

    International Nuclear Information System (INIS)

    Collins, H.D.; Busse, L.J.; Lemon, D.K.

    1983-01-01

    This paper describes the emission linear pulse holography which produces a chronological linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. A thirty two point sampling array is used to construct phase-only linear holograms of simulated acoustic emission sources on large metal plates. The concept behind the AE linear pulse holography is illustrated, and a block diagram of a data acquisition system to implement the concept is given. Array element spacing, synthetic frequency criteria, and lateral depth resolution are specified. A reference timing transducer positioned between the array and the inspection zone and which inititates the time-of-flight measurements is described. The results graphically illustrate the technique using a one-dimensional FFT computer algorithm (ie. linear backward wave) for an AE image reconstruction

  8. Interior acoustic cloak

    Directory of Open Access Journals (Sweden)

    Wael Akl

    2014-12-01

    Full Text Available Acoustic cloaks have traditionally been intended to externally surround critical objects to render these objects acoustically invisible. However, in this paper, the emphasis is placed on investigating the application of the acoustic cloaks to the interior walls of acoustic cavities in an attempt to minimize the noise levels inside these cavities. In this manner, the acoustic cloaks can serve as a viable and efficient alternative to the conventional passive noise attenuation treatments which are invariably heavy and bulky. The transformation acoustics relationships that govern the operation of this class of interior acoustic cloaks are presented. Physical insights are given to relate these relationships to the reasons behind the effectiveness of the proposed interior acoustic cloaks. Finite element models are presented to demonstrate the characteristics of interior acoustic cloaks used in treating the interior walls of circular and square cavities both in the time and frequency domains. The obtained results emphasize the effectiveness of the proposed interior cloaks in eliminating the reflections of the acoustic waves from the walls of the treated cavities and thereby rendering these cavities acoustically quiet. It is important to note here that the proposed interior acoustic cloaks can find applications in acoustic cavities such as aircraft cabins and auditoriums as well as many other critical applications.

  9. Multiple Δt strategy for particle image velocimetry (PIV) error correction, applied to a hot propulsive jet

    International Nuclear Information System (INIS)

    Nogueira, J; Lecuona, A; Nauri, S; Legrand, M; Rodríguez, P A

    2009-01-01

    PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and performance, namely peak-locking and contemporary CCD camera read-out errors. Although the procedures are of general application to PIV, they are applied to a particular real case, giving an example of the methodology steps and the improvement in results that can be obtained. This real case corresponds to an ensemble of hot high-speed coaxial jets, representative of the civil transport aircraft propulsion system using turbofan engines. Errors of ∼0.1 pixels displacements have been assessed. This means 10% of the measured magnitude at many points. These results allow the uncertainty interval associated with the measurement to be provided and, under some circumstances, the correction of some of the bias components of the errors. The detection of conditions where the peak-locking error has a period of 2 pixels instead of the classical 1 pixel has been made possible using these procedures. In addition to the increased worth of the measurement, the uncertainty assessment is of interest for the validation of CFD codes

  10. An Adjoint Sensitivity Method Applied to Time Reverse Imaging of Tsunami Source for the 2009 Samoa Earthquake

    Science.gov (United States)

    Hossen, M. Jakir; Gusman, Aditya; Satake, Kenji; Cummins, Phil R.

    2018-01-01

    We have previously developed a tsunami source inversion method based on "Time Reverse Imaging" and demonstrated that it is computationally very efficient and has the ability to reproduce the tsunami source model with good accuracy using tsunami data of the 2011 Tohoku earthquake tsunami. In this paper, we implemented this approach in the 2009 Samoa earthquake tsunami triggered by a doublet earthquake consisting of both normal and thrust faulting. Our result showed that the method is quite capable of recovering the source model associated with normal and thrust faulting. We found that the inversion result is highly sensitive to some stations that must be removed from the inversion. We applied an adjoint sensitivity method to find the optimal set of stations in order to estimate a realistic source model. We found that the inversion result is improved significantly once the optimal set of stations is used. In addition, from the reconstructed source model we estimated the slip distribution of the fault from which we successfully determined the dipping orientation of the fault plane for the normal fault earthquake. Our result suggests that the fault plane dip toward the northeast.

  11. Multiple Δt strategy for particle image velocimetry (PIV) error correction, applied to a hot propulsive jet

    Science.gov (United States)

    Nogueira, J.; Lecuona, A.; Nauri, S.; Legrand, M.; Rodríguez, P. A.

    2009-07-01

    PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and performance, namely peak-locking and contemporary CCD camera read-out errors. Although the procedures are of general application to PIV, they are applied to a particular real case, giving an example of the methodology steps and the improvement in results that can be obtained. This real case corresponds to an ensemble of hot high-speed coaxial jets, representative of the civil transport aircraft propulsion system using turbofan engines. Errors of ~0.1 pixels displacements have been assessed. This means 10% of the measured magnitude at many points. These results allow the uncertainty interval associated with the measurement to be provided and, under some circumstances, the correction of some of the bias components of the errors. The detection of conditions where the peak-locking error has a period of 2 pixels instead of the classical 1 pixel has been made possible using these procedures. In addition to the increased worth of the measurement, the uncertainty assessment is of interest for the validation of CFD codes.

  12. Micromachined silicon acoustic delay line with improved structural stability and acoustic directivity for real-time photoacoustic tomography

    Science.gov (United States)

    Cho, Young; Kumar, Akhil; Xu, Song; Zou, Jun

    2017-03-01

    Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. However, as its length increases to provide longer delay time, the delay line becomes more vulnerable to structural instability due to reduced mechanical stiffness. In addition, the small cross-section area of the delay line results in a large acoustic acceptance angle and therefore poor directivity. To address these two issues, this paper reports the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, a new tapered design for the input terminal of the delay line was also investigate to improve its acoustic directivity by reducing the acoustic acceptance angle. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

  13. Multichannel analysis of surface-waves and integration of downhole acoustic televiewer imaging, ultrasonic Vs and Vp, and vertical seismic profiling in an NEHRP-standard classification, South of Concordia, Kansas, USA

    Science.gov (United States)

    Raef, Abdelmoneam; Gad, Sabreen; Tucker-Kulesza, Stacey

    2015-10-01

    Seismic site characteristics, as pertaining to earthquake hazard reduction, are a function of the subsurface elastic moduli and the geologic structures. This study explores how multiscale (surface, downhole, and laboratory) datasets can be utilized to improve "constrained" average Vs30 (shear-wave velocity to a 30-meter depth). We integrate borehole, surface and laboratory measurements for a seismic site classification based on the standards of the National Earthquake Hazard Reduction Program (NEHRP). The seismic shear-wave velocity (Vs30) was derived from a geophysical inversion workflow that utilized multichannel analysis of surface-waves (MASW) and downhole acoustic televiewer imaging (DATI). P-wave and S-wave velocities, based on laboratory measurements of arrival times of ultrasonic-frequency signals, supported the workflow by enabling us to calculate Poisson's ratio, which was incorporated in building an initial model for the geophysical inversion of MASW. Extraction of core samples from two boreholes provided lithology and thickness calibration of the amplitudes of the acoustic televiewer imaging for each layer. The MASW inversion, for calculating Vs sections, was constrained with both ultrasonic laboratory measurements (from first arrivals of Vs and Vp waveforms at simulated in situ overburden stress conditions) and the downhole acoustic televiewer (DATV) amplitude logs. The Vs30 calculations enabled categorizing the studied site as NEHRP-class "C" - very dense soil and soft rock. Unlike shallow fractured carbonates in the studied area, S-wave and P-wave velocities at ultrasonic frequency for the deeper intact shale core-samples from two boreholes were in better agreement with the corresponding velocities from both a zero-offset vertical seismic profiling (VSP) and inversion of Rayleigh-wave velocity dispersion curves.

  14. Tipping point analysis of ocean acoustic noise

    Science.gov (United States)

    Livina, Valerie N.; Brouwer, Albert; Harris, Peter; Wang, Lian; Sotirakopoulos, Kostas; Robinson, Stephen

    2018-02-01

    We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations) of the time series.

  15. Acoustic signal analysis in the creeping discharge

    International Nuclear Information System (INIS)

    Nakamiya, T; Sonoda, Y; Tsuda, R; Ebihara, K; Ikegami, T

    2008-01-01

    We have previously succeeded in measuring the acoustic signal due to the dielectric barrier discharge and discriminating the dominant frequency components of the acoustic signal. The dominant frequency components appear over 20kHz of acoustic signal by the dielectric barrier discharge. Recently surface discharge control technology has been focused from practical applications such as ozonizer, NO X reactors, light source or display. The fundamental experiments are carried to examine the creeping discharge using the acoustic signal. When the high voltage (6kV, f = 10kHz) is applied to the electrode, the discharge current flows and the acoustic sound is generated. The current, voltage waveforms of creeping discharge and the sound signal detected by the condenser microphone are stored in the digital memory scope. In this scheme, Continuous Wavelet Transform (CWT) is applied to discriminate the acoustic sound of the micro discharge and the dominant frequency components are studied. CWT results of sound signal show the frequency spectrum of wideband up to 100kHz. In addition, the energy distributions of acoustic signal are examined by CWT

  16. Tipping point analysis of ocean acoustic noise

    Directory of Open Access Journals (Sweden)

    V. N. Livina

    2018-02-01

    Full Text Available We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations of the time series.

  17. Holographic acoustic elements for manipulation of levitated objects

    Science.gov (United States)

    Marzo, Asier; Seah, Sue Ann; Drinkwater, Bruce W.; Sahoo, Deepak Ranjan; Long, Benjamin; Subramanian, Sriram

    2015-10-01

    Sound can levitate objects of different sizes and materials through air, water and tissue. This allows us to manipulate cells, liquids, compounds or living things without touching or contaminating them. However, acoustic levitation has required the targets to be enclosed with acoustic elements or had limited manoeuvrability. Here we optimize the phases used to drive an ultrasonic phased array and show that acoustic levitation can be employed to translate, rotate and manipulate particles using even a single-sided emitter. Furthermore, we introduce the holographic acoustic elements framework that permits the rapid generation of traps and provides a bridge between optical and acoustical trapping. Acoustic structures shaped as tweezers, twisters or bottles emerge as the optimum mechanisms for tractor beams or containerless transportation. Single-beam levitation could manipulate particles inside our body for applications in targeted drug delivery or acoustically controlled micro-machines that do not interfere with magnetic resonance imaging.

  18. Transverse acoustic forcing of a round hydrodynamically self-excited jet

    Science.gov (United States)

    Kushwaha, Abhijit Kumar; Mazur, Marek; Worth, Nicholas; Dawson, James; Li, Larry K. B.

    2017-11-01

    Hydrodynamically self-excited jets can readily synchronize with longitudinal acoustic forcing, but their response to transverse acoustic forcing is less clear. In this experimental study, we apply transverse acoustic forcing to an axisymmetric low-density jet at frequencies around its natural global frequency. We place the jet in a rectangular box containing two loudspeakers, one at each end, producing nominally one-dimensional standing pressure waves. By traversing the jet across this box, we subject it to a range of acoustic modes, from purely longitudinal (streamwise) modes at the pressure anti-node to purely transverse (cross-stream) modes at the pressure node. Using time-resolved Background-Oriented Schlieren (BOS) imaging and hot-wire anemometry, we characterize the jet response for different forcing frequencies, amplitudes and mode shapes, providing new insight into the way transverse acoustic oscillations interact with axisymmetric hydrodynamic oscillations. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

  19. In Situ Acoustic Monitoring of Thermal Spray Process Using High-Frequency Impulse Measurements

    Science.gov (United States)

    Tillmann, Wolfgang; Walther, Frank; Luo, Weifeng; Haack, Matthias; Nellesen, Jens; Knyazeva, Marina

    2018-01-01

    In order to guarantee their protective function, thermal spray coatings must be free from cracks, which expose the substrate surface to, e.g., corrosive media. Cracks in thermal spray coatings are usually formed because of tensile residual stresses. Most commonly, the crack occurrence is determined after the thermal spraying process by examination of metallographic cross sections of the coating. Recent efforts focus on in situ monitoring of crack formation by means of acoustic emission analysis. However, the acoustic signals related to crack propagation can be absorbed by the noise of the thermal spraying process. In this work, a high-frequency impulse measurement technique was applied to separate different acoustic sources by visualizing the characteristic signal of crack formation via quasi-real-time Fourier analysis. The investigations were carried out on a twin wire arc spraying process, utilizing FeCrBSi as a coating material. The impact of the process parameters on the acoustic emission spectrum was studied. Acoustic emission analysis enables to obtain global and integral information on the formed cracks. The coating morphology and coating defects were inspected using light microscopy on metallographic cross sections. Additionally, the resulting crack patterns were imaged in 3D by means of x-ray microtomography.

  20. Acoustic Neuroma Educational Video

    Medline Plus

    Full Text Available ... Facts What is acoustic neuroma? Diagnosing Symptoms Side Effects Keywords Questions to ask Choosing a healthcare provider ... Surgery What is acoustic neuroma Diagnosing Symptoms Side effects Question To Ask Treatment Options Back Overview Observation ...