WorldWideScience

Sample records for adaptive hifu noise

  1. Adaptive HIFU noise cancellation for simultaneous therapy and imaging using an integrated HIFU/imaging transducer

    International Nuclear Information System (INIS)

    It was previously demonstrated that it is feasible to simultaneously perform ultrasound therapy and imaging of a coagulated lesion during treatment with an integrated transducer that is capable of high intensity focused ultrasound (HIFU) and B-mode ultrasound imaging. It was found that coded excitation and fixed notch filtering upon reception could significantly reduce interference caused by the therapeutic transducer. During HIFU sonication, the imaging signal generated with coded excitation and fixed notch filtering had a range side-lobe level of less than -40 dB, while traditional short-pulse excitation and fixed notch filtering produced a range side-lobe level of -20 dB. The shortcoming is, however, that relatively complicated electronics may be needed to utilize coded excitation in an array imaging system. It is for this reason that in this paper an adaptive noise canceling technique is proposed to improve image quality by minimizing not only the therapeutic interference, but also the remnant side-lobe 'ripples' when using the traditional short-pulse excitation. The performance of this technique was verified through simulation and experiments using a prototype integrated HIFU/imaging transducer. Although it is known that the remnant ripples are related to the notch attenuation value of the fixed notch filter, in reality, it is difficult to find the optimal notch attenuation value due to the change in targets or the media resulted from motion or different acoustic properties even during one sonication pulse. In contrast, the proposed adaptive noise canceling technique is capable of optimally minimizing both the therapeutic interference and residual ripples without such constraints. The prototype integrated HIFU/imaging transducer is composed of three rectangular elements. The 6 MHz center element is used for imaging and the outer two identical 4 MHz elements work together to transmit the HIFU beam. Two HIFU elements of 14.4 mm x 20.0 mm dimensions could

  2. Adaptive noise

    OpenAIRE

    Viney, Mark; Reece, Sarah E.

    2013-01-01

    In biology, noise implies error and disorder and is therefore something which organisms may seek to minimize and mitigate against. We argue that such noise can be adaptive. Recent studies have shown that gene expression can be noisy, noise can be genetically controlled, genes and gene networks vary in how noisy they are and noise generates phenotypic differences among genetically identical cells. Such phenotypic differences can have fitness benefits, suggesting that evolution can shape noise ...

  3. Adaptive noise cancellation

    CERN Document Server

    Akram, N

    1999-01-01

    In this report we describe the concept of adaptive noise canceling, an alternative method of estimating signals corrupted by additive noise of interference. The method uses 'primary' input containing the corrupted signal and a 'reference' input containing noise correlated in some unknown way with the primary noise, the reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Adaptive filtering before subtraction allows the treatment of inputs that are deterministic or stochastic, stationary or time variable. When the reference input is free of signal and certain other conditions are met then noise in the primary input can be essentially eliminated without signal distortion. It is further shown that the adaptive filter also acts as notch filter. Simulated results illustrate the usefulness of the adaptive noise canceling technique.

  4. An adaptive algorithm for noise rejection.

    Science.gov (United States)

    Lovelace, D E; Knoebel, S B

    1978-01-01

    An adaptive algorithm for the rejection of noise artifact in 24-hour ambulatory electrocardiographic recordings is described. The algorithm is based on increased amplitude distortion or increased frequency of fluctuations associated with an episode of noise artifact. The results of application of the noise rejection algorithm on a high noise population of test tapes are discussed.

  5. Research of Modified LMS Adaptive Noise Cancellation

    Institute of Scientific and Technical Information of China (English)

    YANG Ming-sheng; LI Yan-peng

    2003-01-01

    Noise cancellation is very important in the field of signal processing. In this paper, the designation of a modified LMS Adaptive Noise Cancellation is demonstrated in detail; the model is simulated. We have compared the performance of the new model with the old model. The result of the experiments shows that this designation improves the noise cancellation′s performance greatly.

  6. Adaptive Noise Suppression Using Digital Signal Processing

    Science.gov (United States)

    Kozel, David; Nelson, Richard

    1996-01-01

    A signal to noise ratio dependent adaptive spectral subtraction algorithm is developed to eliminate noise from noise corrupted speech signals. The algorithm determines the signal to noise ratio and adjusts the spectral subtraction proportion appropriately. After spectra subtraction low amplitude signals are squelched. A single microphone is used to obtain both eh noise corrupted speech and the average noise estimate. This is done by determining if the frame of data being sampled is a voiced or unvoiced frame. During unvoice frames an estimate of the noise is obtained. A running average of the noise is used to approximate the expected value of the noise. Applications include the emergency egress vehicle and the crawler transporter.

  7. Adaptive Intelligent Ventilation Noise Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA needs for quiet crew volumes in a space habitat, Physical Optics Corporation (POC) proposes to develop a new Adaptive Intelligent Ventilation Noise...

  8. Adaptive Intelligent Ventilation Noise Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA need for quiet on-orbit crew quarters (CQ), Physical Optics Corporation (POC) proposes to develop a new Adaptive Intelligent Ventilation Noise...

  9. Adaptive avoidance of reef noise.

    Directory of Open Access Journals (Sweden)

    Stephen D Simpson

    Full Text Available Auditory information is widely used throughout the animal kingdom in both terrestrial and aquatic environments. Some marine species are dependent on reefs for adult survival and reproduction, and are known to use reef noise to guide orientation towards suitable habitat. Many others that forage in food-rich inshore waters would, however, benefit from avoiding the high density of predators resident on reefs, but nothing is known about whether acoustic cues are used in this context. By analysing a sample of nearly 700,000 crustaceans, caught during experimental playbacks in light traps in the Great Barrier Reef lagoon, we demonstrate an auditory capability in a broad suite of previously neglected taxa, and provide the first evidence in any marine organisms that reef noise can act as a deterrent. In contrast to the larvae of species that require reef habitat for future success, which showed an attraction to broadcasted reef noise, taxa with a pelagic or nocturnally emergent lifestyle actively avoided it. Our results suggest that a far greater range of invertebrate taxa than previously thought can respond to acoustic cues, emphasising yet further the potential negative impact of globally increasing levels of underwater anthropogenic noise.

  10. Producing Uniform Lesion Pattern in HIFU Ablation

    Science.gov (United States)

    Zhou, Yufeng; Kargl, Steven G.; Hwang, Joo Ha

    2009-04-01

    High intensity focused ultrasound (HIFU) is emerging as a modality for treatment of solid tumors. The temperature at the focus can reach over 65° C denaturing cellular proteins resulting in coagulative necrosis. Typically, HIFU parameters are the same for each treated spot in most HIFU control systems. Because of thermal diffusion from nearby spots, the size of lesions will gradually become larger as the HIFU therapy progresses, which may cause insufficient treatment of initial spots, and over-treatment of later ones. It is found that the produced lesion pattern also depends on the scanning pathway. From the viewpoint of the physician creating uniform lesions and minimizing energy exposure are preferred in tumor ablation. An algorithm has been developed to adaptively determine the treatment parameters for every spot in a theoretical model in order to maintain similar lesion size throughout the HIFU therapy. In addition, the exposure energy needed using the traditional raster scanning is compared with those of two other scanning pathways, spiral scanning from the center to the outside and from the outside to the center. The theoretical prediction and proposed algorithm were further evaluated using transparent gel phantoms as a target. Digital images of the lesions were obtained, quantified, and then compared with each other. Altogether, dynamically changing treatment parameters can improve the efficacy and safety of HIFU ablation.

  11. Fast Noise Compensation and Adaptive Enhancement for Speech Separation

    Directory of Open Access Journals (Sweden)

    Hu Rong

    2008-01-01

    Full Text Available We propose a novel approach to improve adaptive decorrelation filtering- (ADF- based speech source separation in diffuse noise. The effects of noise on system adaptation and separation outputs are handled separately. First, fast noise compensation (NC is developed for adaptation of separation filters, forcing ADF to focus on source separation; next, output noises are suppressed by speech enhancement. By tracking noise components in output cross-correlation functions, the bias effect of noise on the system adaptation objective function is compensated, and by adaptively estimating output noise autocorrelations, the speech separation output is enhanced. For fast noise compensation, a blockwise fast ADF (FADF is implemented. Experiments were conducted on real and simulated diffuse noises. Speech mixtures were generated by convolving TIMIT speech sources with acoustic path impulse responses measured in a real room with reverberation time  second. The proposed techniques significantly improved separation performance and phone recognition accuracy of ADF outputs.

  12. Adaptive Noise Reduction Scheme for Salt and Pepper

    CERN Document Server

    Gebreyohannes, Tina

    2012-01-01

    In this paper, a new adaptive noise reduction scheme for images corrupted by impulse noise is presented. The proposed scheme efficiently identifies and reduces salt and pepper noise. MAG (Mean Absolute Gradient) is used to identify pixels which are most likely corrupted by salt and pepper noise that are candidates for further median based noise reduction processing. Directional filtering is then applied after noise reduction to achieve a good tradeoff between detail preservation and noise removal. The proposed scheme can remove salt and pepper noise with noise density as high as 90% and produce better result in terms of qualitative and quantitative measures of images.

  13. Adaptive noise Wiener filter for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Teh, V; Nia, M E

    2016-03-01

    Noise on scanning electron microscope (SEM) images is studied. Gaussian noise is the most common type of noise in SEM image. We developed a new noise reduction filter based on the Wiener filter. We compared the performance of this new filter namely adaptive noise Wiener (ANW) filter, with four common existing filters as well as average filter, median filter, Gaussian smoothing filter and the Wiener filter. Based on the experiments results the proposed new filter has better performance on different noise variance comparing to the other existing noise removal filters in the experiments. SCANNING 38:148-163, 2016. © 2015 Wiley Periodicals, Inc. PMID:26235517

  14. A new adaptive filtering algorithm for systems with multiplicative noise

    Institute of Scientific and Technical Information of China (English)

    WANG Hui-li; CHEN Xi-xin; LU Qian-hao

    2005-01-01

    Presented here is a new adaptive state filtering algorithm for systems with multiplicative noise. This algorithm estimates the vector state of the system and the statistics of noise when all the statistics of noise are unknown. This filtering algorithm is a simple recursive structure. A simulation example is presented which demonstrates the effectiveness of this filtering algorithm.

  15. Application of Adaptive Filters to Active Noise Control

    Institute of Scientific and Technical Information of China (English)

    PEI Bingnan; LI Chuanguang

    2001-01-01

    A modified LMS algorithm for noise-control is suggested after a mathematical model ofsound-cancellation is established, on the basis of thesound wave interference principle and the physicalmodel of progressive waves in a duct. Its applicationin controlling noise with the frequency range from 100to 800 Hz can be implemented by using the adaptivedigital signal processing technique. The experimentson a pink noise, a broadband noise and a noise takenfrom a tank were made, which show that there existsan attenuation of 11 dB at the frequency of 500 Hzor so, and that the proposed adaptive noise controltechnique is very effective and valid.

  16. Fast Noise Compensation and Adaptive Enhancement for Speech Separation

    Directory of Open Access Journals (Sweden)

    Yunxin Zhao

    2008-07-01

    Full Text Available We propose a novel approach to improve adaptive decorrelation filtering- (ADF- based speech source separation in diffuse noise. The effects of noise on system adaptation and separation outputs are handled separately. First, fast noise compensation (NC is developed for adaptation of separation filters, forcing ADF to focus on source separation; next, output noises are suppressed by speech enhancement. By tracking noise components in output cross-correlation functions, the bias effect of noise on the system adaptation objective function is compensated, and by adaptively estimating output noise autocorrelations, the speech separation output is enhanced. For fast noise compensation, a blockwise fast ADF (FADF is implemented. Experiments were conducted on real and simulated diffuse noises. Speech mixtures were generated by convolving TIMIT speech sources with acoustic path impulse responses measured in a real room with reverberation time T60=0.3 second. The proposed techniques significantly improved separation performance and phone recognition accuracy of ADF outputs.

  17. Locally Adaptive DCT Filtering for Signal-Dependent Noise Removal

    Directory of Open Access Journals (Sweden)

    Oleg V. Tsymbal

    2007-01-01

    Full Text Available This work addresses the problem of signal-dependent noise removal in images. An adaptive nonlinear filtering approach in the orthogonal transform domain is proposed and analyzed for several typical noise environments in the DCT domain. Being applied locally, that is, within a window of small support, DCT is expected to approximate the Karhunen-Loeve decorrelating transform, which enables effective suppression of noise components. The detail preservation ability of the filter allowing not to destroy any useful content in images is especially emphasized and considered. A local adaptive DCT filtering for the two cases, when signal-dependent noise can be and cannot be mapped into additive uncorrelated noise with homomorphic transform, is formulated. Although the main issue is signal-dependent and pure multiplicative noise, the proposed filtering approach is also found to be competing with the state-of-the-art methods on pure additive noise corrupted images.

  18. Adaptive Threshold Median Filter for Multiple-Impulse Noise

    Institute of Scientific and Technical Information of China (English)

    JIANG Bo; HUANG Wei

    2007-01-01

    Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter(ATMF) has been developed by combining the adaptive median filter (AMF) and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed Filter.

  19. Adaptive Liners for Broadband Noise Reduction Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will combine the advantages of adaptive materials with the simplistic passive design of state-of-the-art acoustic liners to provide the ability to tune...

  20. Application of Feedforward Adaptive Active-Noise Control for Reducing Blade Passing Noise in Centrifugal Fans

    Science.gov (United States)

    WU, J.-D.; BAI, M. R.

    2001-02-01

    This paper describes two configurations of feedforward adaptive active-noise control (ANC) technique for reducing blade passing noise in centrifugal fans. In one configuration, the control speaker is installed at the cut-off region of the fan, while in the other configuration at the exit duct. The proposed ANC system is based on the filtered-x least-mean-squares (FXLMS) algorithm with multi-sine synthesized reference signal and frequency counting and is implemented by using a digital signal processor (DSP). Experiments are carried out to evaluate the proposed system for reducing the noise at the blade passing frequency (BPF) and its harmonics at various flow speeds. The results of the experiment indicated that the ANC technique is effective in reducing the blade passing noise for two configurations by using the feedforward adaptive control.

  1. Performance Analysis of LMS Adaptive FIR Filter and RLS Adaptive FIR Filter for Noise Cancellation

    Directory of Open Access Journals (Sweden)

    Jyotsna Yadav

    2013-07-01

    Full Text Available Interest in adaptive filters continues to grow as they begin to find practical real-time applications in areassuch as channel equalization, echo cancellation, noise cancellation and many other adaptive signalprocessing applications. The key to successful adaptive signal processing understands the fundamentalproperties of adaptive algorithms such as LMS, RLS etc. Adaptive filter is used for the cancellation of thenoise component which is overlap with undesired signal in the same frequency range. This paper presentsdesign, implementation and performance comparison of adaptive FIR filter using LMS and RMSalgorithms. MATLAB Simulink environment are used for simulations.

  2. Applications of active adaptive noise control to jet engines

    Science.gov (United States)

    Shoureshi, Rahmat; Brackney, Larry

    1993-01-01

    During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

  3. Reduced rank adaptive filtering in impulsive noise environments

    KAUST Repository

    Soury, Hamza

    2014-11-01

    An impulsive noise environment is considered in this paper. A new aspect of signal truncation is deployed to reduce the harmful effect of the impulsive noise to the signal. A full rank direct solution is derived followed by an iterative solution. The reduced rank adaptive filter is presented in this environment by using two methods for rank reduction, while the minimized objective function is defined using the Lp norm. The results are presented and the efficiency of each method is discussed. © 2014 IEEE.

  4. Background Noise Reduction in Wind Tunnels using Adaptive Noise Cancellation and Cepstral Echo Removal Techniques for Microphone Array Applications

    OpenAIRE

    Spalt, Taylor B

    2010-01-01

    Two experiments were conducted to investigate Adaptive Noise Cancelling and Cepstrum echo removal post-processing techniques on acoustic data from a linear microphone array in an anechoic chamber. A point source speaker driven with white noise was used as the primary signal. The first experiment included a background speaker to provide interference noise at three different Signal-to-Noise Ratios to simulate noise propagating down a wind tunnel circuit. The second experiment contained only the...

  5. Nonlinear mode decomposition: a noise-robust, adaptive decomposition method.

    Science.gov (United States)

    Iatsenko, Dmytro; McClintock, Peter V E; Stefanovska, Aneta

    2015-09-01

    The signals emanating from complex systems are usually composed of a mixture of different oscillations which, for a reliable analysis, should be separated from each other and from the inevitable background of noise. Here we introduce an adaptive decomposition tool-nonlinear mode decomposition (NMD)-which decomposes a given signal into a set of physically meaningful oscillations for any wave form, simultaneously removing the noise. NMD is based on the powerful combination of time-frequency analysis techniques-which, together with the adaptive choice of their parameters, make it extremely noise robust-and surrogate data tests used to identify interdependent oscillations and to distinguish deterministic from random activity. We illustrate the application of NMD to both simulated and real signals and demonstrate its qualitative and quantitative superiority over other approaches, such as (ensemble) empirical mode decomposition, Karhunen-Loève expansion, and independent component analysis. We point out that NMD is likely to be applicable and useful in many different areas of research, such as geophysics, finance, and the life sciences. The necessary matlab codes for running NMD are freely available for download.

  6. Nonlinear mode decomposition: A noise-robust, adaptive decomposition method

    Science.gov (United States)

    Iatsenko, Dmytro; McClintock, Peter V. E.; Stefanovska, Aneta

    2015-09-01

    The signals emanating from complex systems are usually composed of a mixture of different oscillations which, for a reliable analysis, should be separated from each other and from the inevitable background of noise. Here we introduce an adaptive decomposition tool—nonlinear mode decomposition (NMD)—which decomposes a given signal into a set of physically meaningful oscillations for any wave form, simultaneously removing the noise. NMD is based on the powerful combination of time-frequency analysis techniques—which, together with the adaptive choice of their parameters, make it extremely noise robust—and surrogate data tests used to identify interdependent oscillations and to distinguish deterministic from random activity. We illustrate the application of NMD to both simulated and real signals and demonstrate its qualitative and quantitative superiority over other approaches, such as (ensemble) empirical mode decomposition, Karhunen-Loève expansion, and independent component analysis. We point out that NMD is likely to be applicable and useful in many different areas of research, such as geophysics, finance, and the life sciences. The necessary matlab codes for running NMD are freely available for download.

  7. Adaptive bilateral filter for sharpness enhancement and noise removal.

    Science.gov (United States)

    Zhang, Buyue; Allebach, Jan P

    2008-05-01

    In this paper, we present the adaptive bilateral filter (ABF) for sharpness enhancement and noise removal. The ABF sharpens an image by increasing the slope of the edges without producing overshoot or undershoot. It is an approach to sharpness enhancement that is fundamentally different from the unsharp mask (USM). This new approach to slope restoration also differs significantly from previous slope restoration algorithms in that the ABF does not involve detection of edges or their orientation, or extraction of edge profiles. In the ABF, the edge slope is enhanced by transforming the histogram via a range filter with adaptive offset and width. The ABF is able to smooth the noise, while enhancing edges and textures in the image. The parameters of the ABF are optimized with a training procedure. ABF restored images are significantly sharper than those restored by the bilateral filter. Compared with an USM based sharpening method-the optimal unsharp mask (OUM), ABF restored edges are as sharp as those rendered by the OUM, but without the halo artifacts that appear in the OUM restored image. In terms of noise removal, ABF also outperforms the bilateral filter and the OUM. We demonstrate that ABF works well for both natural images and text images. PMID:18390373

  8. An adaptive noise attenuation method for edge and amplitude preservation

    Institute of Scientific and Technical Information of China (English)

    Cai Han-Peng; He Zhen-Hua; Li Ya-Lin; He Guang-Ming; Zou Wen; Zhang Dong-Jun; Liu Pu

    2014-01-01

    Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and the subsequent seismic data interpretation, reservoir description, hydrocarbon detection, etc. Hence, we propose an adaptive noise attenuation method for edge and amplitude preservation, wherein the wavelet packet transform is used to decompose the full-band seismic signal into multiband data and then process these data using nonlinear anisotropic dip-oriented edge-preservingfi ltering. In the fi ltering, the calculated diffusion tensor from the structure tensor can be exploited to establish the direction of smoothing. In addition, the fault confidence measure and discontinuity operator can be used to preserve the structural and stratigraphic discontinuities and edges, and the decorrelation criteria can be used to establish the number of iterations. These parameters can minimize the intervention and subjectivity of the interpreter, and simplify the application of the proposed method. We applied the proposed method to synthetic and real 3D marine seismic data. We found that the proposed method could be used to attenuate noise in seismic data while preserving the effective discontinuity information and amplitude characteristics in seismic refl ection waves, providing high-quality data for interpretation and analysis such as high-resolution processing, attribute analysis, and inversion.

  9. Simulation and Performance Analysis of Adaptive Filtering Algorithms in Noise Cancellation

    CERN Document Server

    Ferdouse, Lilatul; Nipa, Tamanna Haque; Jaigirdar, Fariha Tasmin

    2011-01-01

    Noise problems in signals have gained huge attention due to the need of noise-free output signal in numerous communication systems. The principal of adaptive noise cancellation is to acquire an estimation of the unwanted interfering signal and subtract it from the corrupted signal. Noise cancellation operation is controlled adaptively with the target of achieving improved signal to noise ratio. This paper concentrates upon the analysis of adaptive noise canceller using Recursive Least Square (RLS), Fast Transversal Recursive Least Square (FTRLS) and Gradient Adaptive Lattice (GAL) algorithms. The performance analysis of the algorithms is done based on convergence behavior, convergence time, correlation coefficients and signal to noise ratio. After comparing all the simulated results we observed that GAL performs the best in noise cancellation in terms of Correlation Coefficient, SNR and Convergence Time. RLS, FTRLS and GAL were never evaluated and compared before on their performance in noise cancellation in ...

  10. HIFU for palliative treatment of pancreatic cancer

    OpenAIRE

    Khokhlova, Tatiana D.; Hwang, Joo Ha

    2011-01-01

    High intensity focused ultrasound (HIFU) is a novel non-invasive modality for ablation of various solid tumors including uterine fibroids, prostate cancer, hepatic, renal, breast and pancreatic tumors. HIFU therapy utilizes mechanical energy in the form of a powerful ultrasound wave that is focused inside the body to induce thermal and/or mechanical effects in tissue. Multiple preclinical and non-randomized clinical trials have been performed to evaluate the safety and efficacy of HIFU for pa...

  11. Combined MIMO adaptive and decentralized controllers for broadband active noise and vibration control

    NARCIS (Netherlands)

    Berkhoff, A.P.; Wesselink, J.M.

    2009-01-01

    Recent implementations of multiple-input multiple-output adaptive controllers for reduction of broadband noise and vibrations provide considerably improved performance over traditional adaptive algorithms. The most significant performance improvements are in terms of speed of convergence, the amount

  12. Adaptive de-noising method based on wavelet and adaptive learning algorithm in on-line PD monitoring

    Institute of Scientific and Technical Information of China (English)

    王立欣; 诸定秋; 蔡惟铮

    2002-01-01

    It is an important step in the online monitoring of partial discharge (PD) to extract PD pulses from various background noises. An adaptive de-noising method is introduced for adaptive noise reduction during detection of PD pulses. This method is based on Wavelet Transform (WT) , and in the wavelet domain the noises decomposed at the levels are reduced by independent thresholds. Instead of the standard hard thresholding function, a new type of hard thresholding function with continuous derivative is employed by this method. For the selection of thresholds, an unsupervised learning algorithm based on gradient in a mean square error (MSE) is present to search for the optimal threshold for noise reduction, and the optimal threshold is selected when the minimum MSE is obtained. With the simulating signals and on-site experimental data processed by this method,it is shown that the background noises such as narrowband noises can be reduced efficiently. Furthermore, it is proved that in comparison with the conventional wavelet de-noising method the adaptive de-noising method has a better performance in keeping the pulses and is more adaptive when suppressing the background noises of PD signals.

  13. A Three-Microphone Adaptive Noise Canceller for Minimizing Reverberation and Signal Distortion

    OpenAIRE

    Zayed M. Ramadan

    2008-01-01

    This paper introduces an adaptive noise canceller (ANC) to improve the system performance in the presence of signal leakage components. The proposed ANC consists of two adaptive filters and three microphones. The first adaptive filter cancels the signal leakage and the second filter cancels the noise. For best results, a least mean squares adaptive algorithm was also introduced and used in the proposed ANC. In this algorithm the step size was based on both error vector and data normalization....

  14. Micro-bubble enhanced HIFU

    Science.gov (United States)

    Kajiyama, K.; Yoshinaka, K.; Takagi, S.; Matsumoto, Y.

    2010-01-01

    High intensity focused ultrasound (HIFU) treatment that employs microbubbles to provide enhanced heating has been investigated in order to develop a less invasive and more rapid tumor ablation therapy. It has been demonstrated that microbubbles have significant effects on heating enhancement in vitro and in vivo experiments, however ultrasound propagation could be disturbed when there are too many microbubbles between the transducer and the focus. In this study, we develop a method to make a clear pass way for obtaining enhanced heating by using microbubbles just at the focus, thus avoiding heating on the pass way from the transducer to the target region. In this method, microbubbles are destroyed in front of the HIFU focus (on the transducer side) by irradiating a intense burst wave of microsecond order, before irradiating the ultrasound waves for heating the target region. The experiment is conducted in a medium of a polyacrylamide gel containing microbubbles, and a temperature-sensing liquid crystal sheet is set in the focus to observe the temperature distribution. The ultrasound frequency was 2.2 MHz and the intensity was 5000 W/cm2, and 20 burst waves were irradiated at pulse repetition frequency of 1 kHz. The number of wave pulses was varied. The continuous-wave frequency, intensity and irradiation time are 2.2 MHz, 1000 W/cm2 and 60 sec, respectively. As the number of pulses increased, the heating region moves from the transducer side to the focus. This is because microbubbles in front of the focus are destroyed and the ultrasound propagates around the target position effectively. These results suggest that the microbubble distribution and the heating position in the developed HIFU system can be controlled.

  15. AN AMELIORATED DETECTION STATISTICS FOR ADAPTIVE MASK MEDIAN FILTRATION OF HEAVILY NOISED DIGITAL IMAGES

    Directory of Open Access Journals (Sweden)

    Geeta Hanji

    2016-11-01

    Full Text Available Noise reduction is an important area of research in image processing applications. The performance of the digital image noise filtering method primarily depends upon the accuracy of noise detection scheme. This paper presents an effective detector based, adaptive mask, median filtration of heavily noised digital images affected with fixed value (or salt and pepper impulse noise. The proposed filter presents a novel approach; an ameliorated Rank Ordered Absolute Deviation (ROAD statistics to judge whether the input pixel is noised or noise free. If a pixel is detected as corrupted, it is subjected to adaptive mask median filtration; otherwise, it is kept unchanged. Extensive experimental results and comparative performance evaluations demonstrate that the proposed filter outperforms the existing decision type, median based filters with powerful noise detectors in terms of objective performance measures and visual retrieviation accuracy.

  16. Adaptive Feed-Forward Control of Low Frequency Interior Noise

    CERN Document Server

    Kletschkowski, Thomas

    2012-01-01

    This book presents a mechatronic approach to Active Noise Control (ANC). It describes the required elements of system theory, engineering acoustics, electroacoustics and adaptive signal processing in a comprehensive, consistent and systematic manner using a unified notation. Furthermore, it includes a design methodology for ANC-systems, explains its application and describes tools to be used for ANC-system design. From the research point of view, the book presents new approaches to sound source localization in weakly damped interiors. One is based on the inverse finite element method, the other is based on a sound intensity probe with an active free field. Furthermore, a prototype of an ANC-system able to reach the physical limits of local (feed-forward) ANC is described. This is one example for applied research in ANC-system design. Other examples are given for (i) local ANC in a semi-enclosed subspace of an aircraft cargo hold and (ii) for the combination of audio entertainment with ANC.

  17. Emerging HIFU applications in cancer therapy.

    Science.gov (United States)

    Maloney, Ezekiel; Hwang, Joo Ha

    2015-05-01

    High intensity focused ultrasound (HIFU), is a promising, non-invasive modality for treatment of tumours in conjunction with magnetic resonance imaging or diagnostic ultrasound guidance. HIFU is being used increasingly for treatment of prostate cancer and uterine fibroids. Over the last 10 years a growing number of clinical trials have examined HIFU treatment of both benign and malignant tumours of the liver, breast, pancreas, bone, connective tissue, thyroid, parathyroid, kidney and brain. For some of these emerging indications, HIFU is poised to become a serious alternative or adjunct to current standard treatments--including surgery, radiation, gene therapy, immunotherapy, and chemotherapy. Current commercially available HIFU devices are marketed for their thermal ablation applications. In the future, lower energy treatments may play a significant role in mediating targeted drug and gene delivery for cancer treatment. In this article we introduce currently available HIFU systems, provide an overview of clinical trials in emerging oncological targets, and briefly discuss selected pre-clinical research that is relevant to future oncological HIFU applications. PMID:25367011

  18. Industrial wideband noise reduction for hearing aids using a headset with adaptive-feedback active noise cancellation.

    Science.gov (United States)

    Lin, J H; Li, P C; Tang, S T; Liu, P T; Young, S T

    2005-11-01

    High-intensity noises are a health hazard for industrial workers, and hearing protection is necessary to prevent hearing loss. Passive methods, such as ear muffs, are ineffective against low-frequency noise. Moreover, many hearing-impaired workers must wear hearing aids to enable communication at their workplace, and such aids can amplify ambient noise. To overcome this problem, the present study developed a headset equipped with a digital signal processing system to implement adaptive-feedback active noise cancellation (AFANC) to reduce low-frequency noise. The proposed AFANC headset was effective against wideband industrial noise, with a maximum noise spectrum power reduction of 30 dB. Furthermore, when used with a hearing aid, it improved the speech signal-to-noise ratio by up to 14 dB. These results suggest that a headset with AFANC would be useful for hearing protection in workplaces with high levels of low-frequency industrial noise, especially for hearing-impaired workers. PMID:16594300

  19. Noise Estimation from Remote Sensing Images by Fractal Theory and Adaptive Image Block Division

    Directory of Open Access Journals (Sweden)

    FU Peng

    2015-11-01

    Full Text Available A novel approach for additive noise estimation from highly textured optical remote sensing images has been proposed, which is based on fractal theory and adaptive image block division. Different from the conventional regular block division based noise estimation methods, the divided adaptive image blocks with the proposed method are adhering to the local image information, which are most likely to be homogeneous blocks. Combining with the week textured image region detection using fractal theory and noise standard deviation calculation using statistical analysis, the proposed method can automatically estimate additive noise intensity from optical remote sensing images. Quantified analysis of experiments with ZY-3 satellite images demonstrates that the proposed method is applicable to optical remote sensing images with various complexities and different noise levels. Meanwhile, the notion of week textured image region detection and adaptive image block division can also be applied to multiplicative noise estimation from radar images after modification.

  20. Adaptive Noise Cancellation Method Used for Wheel Speed Signal of Integrate ABS/ASR System

    Institute of Scientific and Technical Information of China (English)

    MA Yue-feng; LIU Zhao-du; QI Zhi-quan; CUI Hai-feng

    2006-01-01

    A novel adaptive noise cancellation method for wheel speed signal of the anti-lock braking system/anti-slip regulation(ABS/ASR) control system is proposed. Based on the spectrum distribution of vehicle's wheel speed signal got from fast Fourier transform under various conditions, the high-pass filter is used to deal with original wheel speed signals sampled to get reference noise signal and the original wheel speed signals are used as adaptive filter's desired outputs. The difference between original signals and reference noise signals is used as the error signal for the adaptive FIR filter and also used as the whole adaptive noise cancellation system's final output. This method can obtain the noise signal on-line and is easy to use for real control system,which is useful to improve the performance of integrate system ABS/ASR.

  1. Object detection in ultrasound elastography for use in HIFU treatment of cancer

    Science.gov (United States)

    Huang, Alex; Mankani, Soumya; Choo, Chang

    2014-03-01

    High intensity focused ultrasound (HIFU), has applications in treating various cancers, such as prostate, liver and breast cancer. In order for HIFU to be effective and efficient it needs to be guided by an imaging modality. While there are several options for guiding HIFU treatment, one of the most promising is ultrasound elastography. Current commercial devices use Brightness-Mode (B-mode) imaging or MRI, and are manual processes. Ultrasound elastography, allows complete automation of HIFU treatment due to the enhanced image, that elastography provides. The elastic image provides more information and less noise. To show that segmentation was possible on elastic images, nine algorithms were implemented in matlab and used on three distinct images for object detection. The three images used, have varying properties regarding object intensity and placement, as well as different noise patterns. Using PSNR, to gauge the effectiveness of each algorithm, it was shown that segmentation was possible on all images using different algorithms. The bilateral-shock-bilateral algorithm proved to be an overall effective algorithm in every situation with a PSNR of 83.87db on the phantom image. The segmentation results clearly highlight any object in the images. Future work includes fine tuning the algorithm with different phantom images and in-vivo images to distinguish between noise and desired object.

  2. Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

    Science.gov (United States)

    Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

    2014-01-01

    Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method.

  3. Adaptive neuro-fuzzy methodology for noise assessment of wind turbine.

    Science.gov (United States)

    Shamshirband, Shahaboddin; Petković, Dalibor; Hashim, Roslan; Motamedi, Shervin

    2014-01-01

    Wind turbine noise is one of the major obstacles for the widespread use of wind energy. Noise tone can greatly increase the annoyance factor and the negative impact on human health. Noise annoyance caused by wind turbines has become an emerging problem in recent years, due to the rapid increase in number of wind turbines, triggered by sustainable energy goals set forward at the national and international level. Up to now, not all aspects of the generation, propagation and perception of wind turbine noise are well understood. For a modern large wind turbine, aerodynamic noise from the blades is generally considered to be the dominant noise source, provided that mechanical noise is adequately eliminated. The sources of aerodynamic noise can be divided into tonal noise, inflow turbulence noise, and airfoil self-noise. Many analytical and experimental acoustical studies performed the wind turbines. Since the wind turbine noise level analyzing by numerical methods or computational fluid dynamics (CFD) could be very challenging and time consuming, soft computing techniques are preferred. To estimate noise level of wind turbine, this paper constructed a process which simulates the wind turbine noise levels in regard to wind speed and sound frequency with adaptive neuro-fuzzy inference system (ANFIS). This intelligent estimator is implemented using Matlab/Simulink and the performances are investigated. The simulation results presented in this paper show the effectiveness of the developed method. PMID:25075621

  4. Active noise control using noise source having adaptive resonant frequency tuning through stiffness variation

    Science.gov (United States)

    Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)

    1995-01-01

    A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by a plurality of force transmitting mechanisms which contact the noise radiating element. Each one of the force transmitting mechanisms includes an expandable element and a spring in contact with the noise radiating element so that excitation of the element varies the spring force applied to the noise radiating element. The elements are actuated by a controller which receives input of a signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the spring force applied to the noise radiating element to be varied. The force transmitting mechanisms can be arranged to either produce bending or linear stiffness variations in the noise radiating element.

  5. Safety Issues for HIFU Transducer Design

    Science.gov (United States)

    Fleury, Gérard; Berriet, Rémi; Chapelon, Jean Yves; ter Haar, Gail; Lafon, Cyril; Le Baron, Olivier; Chupin, Laurent; Pichonnat, Fabrice; Lenormand, Jérôme

    2005-03-01

    In contrast with most ultrasound modalities for medical applications, (especially ultrasound imaging), High Intensity Focused Ultrasound (HIFU) involves technologies and procedures which may present risk to the patient. These risks, resulting from the high power levels required for effective therapy, should be taken into account at the earliest stages in the design of a system dedicated to HIFU treatment. An understanding of these risks must thus be shared amongst the many players in the field of therapy using high power ultrasound. Moreover, since the number of applications of HIFU has increased appreciably over recent years and the technology is ready to move from the research to the industrial level, it is worth now considering solutions that should be put in place to guarantee the safety of the patient during HIFU treatment. This paper reports thoughts on this, identifies some risks to the patient that must be taken into consideration in the design of HIFU transducers, and proposes some solutions that could prevent the deleterious consequences of transducer misuse or failure. For the main risks identified, such as exceeding the desired acoustic power or poor control of tissue targeting, a description of transducer performance that could potentially result in problems is systematically sought. This allows proposals for precautions to be taken during operation to be made. Parameters which should be monitored to ensure safe use are also suggested. This type of approach, which should be undertaken for the different components of a therapeutic system, highlights the challenges that must be faced in the immediate future for the development and safe exploitation of HIFU systems. The necessity for standard definitions of the parameters to be checked or monitored during HIFU treatments is crucial in this approach, as is the availability of reliable dedicated measurement devices. Co-ordinated action on these topics in the HIFU community would contribute to the

  6. Adaptive cyclic physiologic noise modeling and correction in functional MRI.

    Science.gov (United States)

    Beall, Erik B

    2010-03-30

    Physiologic noise in BOLD-weighted MRI data is known to be a significant source of the variance, reducing the statistical power and specificity in fMRI and functional connectivity analyses. We show a dramatic improvement on current noise correction methods in both fMRI and fcMRI data that avoids overfitting. The traditional noise model is a Fourier series expansion superimposed on the periodicity of parallel measured breathing and cardiac cycles. Correction using this model results in removal of variance matching the periodicity of the physiologic cycles. Using this framework allows easy modeling of noise. However, using a large number of regressors comes at the cost of removing variance unrelated to physiologic noise, such as variance due to the signal of functional interest (overfitting the data). It is our hypothesis that there are a small variety of fits that describe all of the significantly coupled physiologic noise. If this is true, we can replace a large number of regressors used in the model with a smaller number of the fitted regressors and thereby account for the noise sources with a smaller reduction in variance of interest. We describe these extensions and demonstrate that we can preserve variance in the data unrelated to physiologic noise while removing physiologic noise equivalently, resulting in data with a higher effective SNR than with current corrections techniques. Our results demonstrate a significant improvement in the sensitivity of fMRI (up to a 17% increase in activation volume for fMRI compared with higher order traditional noise correction) and functional connectivity analyses.

  7. Active noise control using noise source having adaptive resonant frequency tuning through stress variation

    Science.gov (United States)

    Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)

    1995-01-01

    A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.

  8. Shape anomaly detection under strong measurement noise: An analytical approach to adaptive thresholding

    Science.gov (United States)

    Krasichkov, Alexander S.; Grigoriev, Eugene B.; Bogachev, Mikhail I.; Nifontov, Eugene M.

    2015-10-01

    We suggest an analytical approach to the adaptive thresholding in a shape anomaly detection problem. We find an analytical expression for the distribution of the cosine similarity score between a reference shape and an observational shape hindered by strong measurement noise that depends solely on the noise level and is independent of the particular shape analyzed. The analytical treatment is also confirmed by computer simulations and shows nearly perfect agreement. Using this analytical solution, we suggest an improved shape anomaly detection approach based on adaptive thresholding. We validate the noise robustness of our approach using typical shapes of normal and pathological electrocardiogram cycles hindered by additive white noise. We show explicitly that under high noise levels our approach considerably outperforms the conventional tactic that does not take into account variations in the noise level.

  9. Sequentially Adapted Parallel Feedforward Active Noise Control of Noisy Sinusoidal Signals

    Directory of Open Access Journals (Sweden)

    Govind Kannan

    2009-01-01

    Full Text Available A large class of acoustic noise sources has an underlying periodic process that generates a periodic noise component, and thus their acoustic noise can in general be modeled as the sum of a periodic signal and a randomly fluctuating signal (usually a broadband background noise. Active control of periodic noise (i.e., for a mixture of sinusoids is more effective than that of random noise. For mixtures of sinusoids in a background broadband random noise, conventional FXLMS-based single filter method does not reach the maximum achievable Noise Attenuation Level (NALmax⁡. In this paper, an alternative approach is taken and the idea of a parallel active noise control (ANC architecture for cancelling mixtures of periodic and random signals is presented. The proposed ANC system separates the noise into periodic and random components and generates corresponding antinoises via separate noise cancelling filters, and tends to reach NALmax⁡ consistently. The derivation of NALmax⁡ is presented. Both the separation and noise cancellation are based on adaptive filtering. Experimental results verify the analytical development by showing superior performance of the proposed method, over the single-filter approach, for several cases of sinusoids in white noise.

  10. Time-shared channel identification for adaptive noise cancellation in breath sound extraction

    Institute of Scientific and Technical Information of China (English)

    Zheng HAN; Hong WANG; Leyi WANG; Gang George YIN

    2004-01-01

    Noise artifacts are one of the key obstacles in applying continuous monitoring and computer-assisted analysis of lung sounds.Traditional adaptive noise cancellation (ANC) methodologies work reasonably well when signal and noise are stationary and independent.Clinical lung sound auscultation encounters an acoustic environment in which breath sounds are not stationary and often correlate with noise.Consequently,capability of ANC becomes significantly compromised.This paper introduces a new methodology for extracting authentic lung sounds from noise-corrupted measurements.Unlike traditional noise cancellation methods that rely on either frequency band separation or signal/noise independence to achieve noise reduction,this methodology combines the traditional noise canceling methods with the unique feature of time-split stages in breathing sounds.By employing a multi-sensor system,the method first employs a high-pass filter to eliminate the off-band noise,and then performs time-shared blind identification and noise cancellation with recursion from breathing cycle to cycle.Since no frequency separation or signal/noise independence is required,this method potentially has a robust and reliable capability of noise reduction,complementing the traditional methods.

  11. A Three-Microphone Adaptive Noise Canceller for Minimizing Reverberation and Signal Distortion

    Directory of Open Access Journals (Sweden)

    Zayed M. Ramadan

    2008-01-01

    Full Text Available This paper introduces an adaptive noise canceller (ANC to improve the system performance in the presence of signal leakage components. The proposed ANC consists of two adaptive filters and three microphones. The first adaptive filter cancels the signal leakage and the second filter cancels the noise. For best results, a least mean squares adaptive algorithm was also introduced and used in the proposed ANC. In this algorithm the step size was based on both error vector and data normalization. Simulation results, carried out using a real speech, demonstrate significant improvements of the proposed ANC over the conventional one in minimizing signal distortion and reverberation.

  12. Active noise control using noise source having adaptive resonant frequency tuning through variable ring loading

    Science.gov (United States)

    Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)

    1995-01-01

    A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

  13. Stabilization of the distribution of the product output in adaptive receivers noise signal

    Directory of Open Access Journals (Sweden)

    Yu. L. Mazor

    1986-04-01

    Full Text Available The algorithm of adaptive receiving noise signals on the background noise interference with monotonically varying spectra, allowing through the introduction of a reference path to stabilize the distribution of the output product. With the help of computer modeling an estimate of the effectiveness of the proposed algorithm.

  14. Adaptive filters of stationary-noise compensation which correspond to a Toeplitz correlation-matrix structure

    Science.gov (United States)

    Abramovich, Iu. I.; Arov, D. Z.; Kachur, V. G.

    1987-12-01

    The paper considers the problem of finding the vector of an adaptive filter of stationary-noise compensation which corresponds to a Toeplitz correlation-matrix structure. The existence of a Toeplitz solution is demonstrated. Lower-bound estimates are obtained for the gain in noise-compensation efficiency using a priori information about the Toeplitz matrix structure. Constructive methods for obtaining adaptive solutions corresponding to these estimates are indicated.

  15. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG) demonstrated feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners. This was...

  16. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to demonstrate feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners....

  17. Adaptive noise estimation and suppression for improving microseismic event detection

    Science.gov (United States)

    Mousavi, S. Mostafa; Langston, Charles A.

    2016-09-01

    Microseismic data recorded by surface arrays are often strongly contaminated by unwanted noise. This background noise makes the detection of small magnitude events difficult. A noise level estimation and noise reduction algorithm is presented for microseismic data analysis based upon minimally controlled recursive averaging and neighborhood shrinkage estimators. The method might not be compared with more sophisticated and computationally expensive denoising algorithm in terms of preserving detailed features of seismic signal. However, it is fast and data-driven and can be applied in real-time processing of continuous data for event detection purposes. Results from application of this algorithm to synthetic and real seismic data show that it holds a great promise for improving microseismic event detection.

  18. Adaptive filter based two-probe noise suppression system for transient evoked otoacoustic emission detection.

    Science.gov (United States)

    Subotić, Miško; Šarić, Zoran; Jovičić, Slobodan T

    2012-03-01

    Transient otoacoustic emission (TEOAE) is a method widely used in clinical practice for assessment of hearing quality. The main problem in TEOAE detection is its much lower level than the level of environmental and biological noise. While the environmental noise level can be controlled, the biological noise can be only reduced by appropriate signal processing. This paper presents a new two-probe preprocessing TEOAE system for suppression of the biological noise by adaptive filtering. The system records biological noises in both ears and applies a specific adaptive filtering approach for suppression of biological noise in the ear canal with TEOAE. The adaptive filtering approach includes robust sign error LMS algorithm, stimuli response summation according to the derived non-linear response (DNLR) technique, subtraction of the estimated TEOAE signal and residual noise suppression. The proposed TEOAE detection system is tested by three quality measures: signal-to-noise ratio (S/N), reproducibility of TEOAE, and measurement time. The maximal TEOAE detection improvement is dependent on the coherence function between biological noise in left and right ears. The experimental results show maximal improvement of 7 dB in S/N, improvement in reproducibility near 40% and reduction in duration of TEOAE measurement of over 30%.

  19. Multi-channel differencing adaptive noise cancellation with multi-kernel method

    Institute of Scientific and Technical Information of China (English)

    Wei Gao; Jianguo Huang; Jing Han

    2015-01-01

    Although a various of existing techniques are able to improve the performance of detection of the weak interesting sig-nal, how to adaptively and efficiently attenuate the intricate noises especial y in the case of no available reference noise signal is stil the bottleneck to be overcome. According to the characteristics of sonar arrays, a multi-channel differencing method is presented to provide the prerequisite reference noise. However, the ingre-dient of obtained reference noise is too complicated to be used to effectively reduce the interference noise only using the clas-sical linear cancel ation methods. Hence, a novel adaptive noise cancel ation method based on the multi-kernel normalized least-mean-square algorithm consisting of weighted linear and Gaussian kernel functions is proposed, which al ows to simultaneously con-sider the cancel ation of linear and nonlinear components in the reference noise. The simulation results demonstrate that the out-put signal-to-noise ratio (SNR) of the novel multi-kernel adaptive filtering method outperforms the conventional linear normalized least-mean-square method and the mono-kernel normalized least-mean-square method using the realistic noise data measured in the lake experiment.

  20. Adaptive anisotropic diffusion for noise reduction of phase images in Fourier domain Doppler optical coherence tomography.

    Science.gov (United States)

    Xia, Shaoyan; Huang, Yong; Peng, Shizhao; Wu, Yanfeng; Tan, Xiaodi

    2016-08-01

    Phase image in Fourier domain Doppler optical coherence tomography offers additional flow information of investigated samples, which provides valuable evidence towards accurate medical diagnosis. High quality phase images are thus desirable. We propose a noise reduction method for phase images by combining a synthetic noise estimation criteria based on local noise estimator (LNE) and distance median value (DMV) with anisotropic diffusion model. By identifying noise and signal pixels accurately and diffusing them with different coefficients respectively and adaptive iteration steps, we demonstrated the effectiveness of our proposed method in both phantom and mouse artery images. Comparison with other methods such as filtering method (mean, median filtering), wavelet method, probabilistic method and partial differential equation based methods in terms of peak signal-to-noise ratio (PSNR), equivalent number of looks (ENL) and contrast-to-noise ratio (CNR) showed the advantages of our method in reserving image energy and removing noise. PMID:27570687

  1. PSO Algorithm based Adaptive Median Filter for Noise Removal in Image Processing Application

    Directory of Open Access Journals (Sweden)

    Ruby Verma

    2016-07-01

    Full Text Available A adaptive Switching median filter for salt and pepper noise removal based on genetic algorithm is presented. Proposed filter consist of two stages, a noise detector stage and a noise filtering stage. Particle swarm optimization seems to be effective for single objective problem. Noise Dictation stage works on it. In contrast to the standard median filter, the proposed algorithm generates the noise map of corrupted Image. Noise map gives information about the corrupted and non-corrupted pixels of Image. In filtering, filter calculates the median of uncorrupted neighbouring pixels and replaces the corrupted pixels. Extensive simulations are performed to validate the proposed filter. Simulated results show refinement both in Peak signal to noise ratio (PSNR and Image Quality Index value (IQI. Experimental results shown that proposed method is more effective than existing methods.

  2. Wavelet Adaptive Algorithm and Its Application to MRE Noise Control System

    Directory of Open Access Journals (Sweden)

    Zhang Yulin

    2015-01-01

    Full Text Available To address the limitation of conventional adaptive algorithm used for active noise control (ANC system, this paper proposed and studied two adaptive algorithms based on Wavelet. The twos are applied to a noise control system including magnetorheological elastomers (MRE, which is a smart viscoelastic material characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Simulation results reveal that the Decomposition LMS algorithm (D-LMS and Decomposition and Reconstruction LMS algorithm (DR-LMS based on Wavelet can significantly improve the noise reduction performance of MRE control system compared with traditional LMS algorithm.

  3. Direction-Based Adaptive Switching Filter for Removing High-Density Impulse Noise

    Institute of Scientific and Technical Information of China (English)

    刘会刚; 孙菁; 张福海; 任立儒

    2014-01-01

    A direction-based adaptive switching (DBAS) filter is presented for the removal of high-density impulse noise in images. The extrema detection and 28-directional detection are employed to discriminate the pixels as noisy or noise-free. If a pixel is classified as noisy, it will be replaced by a median or a mean value within an adaptive filter window with respect to different noise densities. Simulation results show that the miss-detection ratio and false-alarm ratio are both very low even at noise level as high as 90%. At the same time, better results are obtained in terms of the qualitative and quantitative measures. The peak signal-to-noise ratios increase by nearly 1 dB compared with other existing algorithms. In addition, the computation time is around 10 s for test images with resolutions of 512´512 since the proposed approach has low complexity.

  4. A NEW DE-NOISING METHOD BASED ON 3-BAND WAVELET AND NONPARAMETRIC ADAPTIVE ESTIMATION

    Institute of Scientific and Technical Information of China (English)

    Li Li; Peng Yuhua; Yang Mingqiang; Xue Peijun

    2007-01-01

    Wavelet de-noising has been well known as an important method of signal de-noising.Recently,most of the research efforts about wavelet de-noising focus on how to select the threshold,where Donoho method is applied widely.Compared with traditional 2-band wavelet,3-band wavelet has advantages in many aspects.According to this theory,an adaptive signal de-noising method in 3-band wavelet domain based on nonparametric adaptive estimation is proposed.The experimental results show that in 3-band wavelet domain,the proposed method represents better characteristics than Donoho method in protecting detail and improving the signal-to-noise ratio of reconstruction signal.

  5. Periodic Noise Suppression from ECG Signal using Novel Adaptive Filtering Techniques

    Directory of Open Access Journals (Sweden)

    Yogesh Sharma

    2012-03-01

    Full Text Available Electrocardiogram signal most commonly known recognized and used biomedical signal for medical examination of heart. The ECG signal is very sensitive in nature, and even if small noise mixed with original signal, the various characteristics of the signal changes, Data corrupted with noise must either filtered or discarded, filtering is important issue for design consideration of real time heart monitoring systems. Various filters used for removing the noise from ECG signals, most commonly used filters are Notch Filters, FIR filters, IIR filters, Wiener filter, Adaptive filters etc. Performance analysis shows that the best result is obtained by using Adaptive filter to remove various noises from ECG signal and get significant SNR andMSE results. In this paper a novel adaptive approach by using LMS algorithm and delay has shown whichcan be used for pre-processing of ECG signal and give appreciable result.

  6. An adaptive clutter and interference suppression with a minimum residue noise power

    Science.gov (United States)

    Kwag, Young Kil

    The author presents an adaptive technique for the suppression of clutter and interference in environments where no a priori knowledge about the target or the clutter and interference statistics is available. The adaptive processor generates the average weight vector, in the sense of minimum-residue-noise power, on the basis of the injected noise-level vector in the weight control algorithm. The set of weight vectors generated in a particular range-azimuth space can be stored and switched to the same sector for the unwanted-noise rejection. The adaptation rate is significantly increased when the residue noise is removed from the combiner output. The system improvement factor in suppressing the clutter and interference is not sensitive to the strength of the input CSR (clutter suppression rate) and is largely dependent on the residue clutter and interference. Simulation results show the effectiveness of the proposed method in improving the clutter and interference rejection capability.

  7. Design and Analysis of a BLPC Vocoder with Probe Noise for Adaptive Feedback Cancellation

    DEFF Research Database (Denmark)

    Kar, Asutosh; Swamy, M.N.S.; Anand, Ankita

    2017-01-01

    a BLPC vocoderbased adaptive feedback canceller with probe noise with an objective of reducing the low-frequency bias in digital hearing-aids. A step-wise mathematical analysis of the proposed feedback canceller is presented employing the recursive least square and normalized least mean square adaptive...

  8. Construction and solution of an adaptive image-restoration model for removing blur and mixed noise

    Science.gov (United States)

    Wang, Youquan; Cui, Lihong; Cen, Yigang; Sun, Jianjun

    2016-03-01

    We establish a practical regularized least-squares model with adaptive regularization for dealing with blur and mixed noise in images. This model has some advantages, such as good adaptability for edge restoration and noise suppression due to the application of a priori spatial information obtained from a polluted image. We further focus on finding an important feature of image restoration using an adaptive restoration model with different regularization parameters in polluted images. A more important observation is that the gradient of an image varies regularly from one regularization parameter to another under certain conditions. Then, a modified graduated nonconvexity approach combined with a median filter version of a spatial information indicator is proposed to seek the solution of our adaptive image-restoration model by applying variable splitting and weighted penalty techniques. Numerical experiments show that the method is robust and effective for dealing with various blur and mixed noise levels in images.

  9. Cavitation damage in blood clots under HIFU

    Science.gov (United States)

    Weiss, Hope; Ahadi, Golnaz; Hoelscher, Thilo; Szeri, Andrew

    2010-11-01

    High Intensity Focused Ultrasound (HIFU) has been shown to accelerate thrombolysis, the dissolution of blood clots, in vitro and in vivo, for treatment of ischemic stroke. Cavitation in sonothrombolysis is thought to play an important role, although the mechanisms are not fully understood. The damage to a blood clot associated with bubble collapses in a HIFU field is studied. The region of damage caused by a bubble collapse on the fibrin network of the blood clot exposed to HIFU is estimated, and compared with experimental assessment of the damage. The mechanical damage to the network caused by a bubble is probed using two independent approaches, a strain based method and an energy based method. Immunoflourescent fibrin staining is used to assess the region of damage experimentally.

  10. A New Adaptive Square-Root Unscented Kalman Filter for Nonlinear Systems with Additive Noise

    Directory of Open Access Journals (Sweden)

    Yong Zhou

    2015-01-01

    Full Text Available The Kalman filter (KF, extended KF, and unscented KF all lack a self-adaptive capacity to deal with system noise. This paper describes a new adaptive filtering approach for nonlinear systems with additive noise. Based on the square-root unscented KF (SRUKF, traditional Maybeck’s estimator is modified and extended to nonlinear systems. The square root of the process noise covariance matrix Q or that of the measurement noise covariance matrix R is estimated straightforwardly. Because positive semidefiniteness of Q or R is guaranteed, several shortcomings of traditional Maybeck’s algorithm are overcome. Thus, the stability and accuracy of the filter are greatly improved. In addition, based on three different nonlinear systems, a new adaptive filtering technique is described in detail. Specifically, simulation results are presented, where the new filter was applied to a highly nonlinear model (i.e., the univariate nonstationary growth model (UNGM. The UNGM is compared with the standard SRUKF to demonstrate its superior filtering performance. The adaptive SRUKF (ASRUKF algorithm can complete direct recursion and calculate the square roots of the variance matrixes of the system state and noise, which ensures the symmetry and nonnegative definiteness of the matrixes and greatly improves the accuracy, stability, and self-adaptability of the filter.

  11. Speech Waveform Compression Using Robust Adaptive Voice Activity Detection for Nonstationary Noise

    Directory of Open Access Journals (Sweden)

    Hsiao-Chun Wu

    2008-03-01

    Full Text Available The voice activity detection (VAD is crucial in all kinds of speech applications. However, almost all existing VAD algorithms suffer from the nonstationarity of both speech and noise. To combat this difficulty, we propose a new voice activity detector, which is based on the Mel-energy features and an adaptive threshold related to the signal-to-noise ratio (SNR estimates. In this paper, we first justify the robustness of the Bayes classifier using the Mel-energy features over that using the Fourier spectral features in various noise environments. Then, we design an algorithm using the dynamic Mel-energy estimator and the adaptive threshold, which depends on the SNR estimates. In addition, a realignment scheme is incorporated to correct the sparse-and-spurious noise estimates. Numerous simulations are carried out to evaluate the performance of our proposed VAD method and the comparisons are made with a couple of existing representative schemes, namely, the VAD using the likelihood ratio test with Fourier spectral energy features and that based on the enhanced time-frequency parameters. Three types of noises, namely, white noise (stationary, babble noise (nonstationary, and vehicular noise (nonstationary were artificially added by the computer for our experiments. As a result, our proposed VAD algorithm significantly outperforms other existing methods as illustrated by the corresponding receiver operating characteristics (ROC curves. Finally, we demonstrate one of the major applications, namely, speech waveform compression associated with our new robust VAD scheme and quantify the effectiveness in terms of compression efficiency.

  12. Implementasi dan Perbandingan Metode Alpha-Trimmed Mean Filter dan Adaptive Media Filter untuk Reduksi Noise pada Citra Digital

    OpenAIRE

    Nababan, Sunfirst Lady Jeanfera

    2015-01-01

    Basically, every image acquisition can cause to the presence of noise in the resulting image. Uniform Noise, Salt & Pepper Noise, and Speckle Noise are three of many model noises that are present in the image. Digital image that contained noise can cause problems in the form of an image that cannot be interpreted properly by human, however noise can be reduce through image restoration called filtering. Filter method that can be used to reduce the noises are Alpha-Trimmed Mean Filter and Adapt...

  13. HIFU as a Neoadjuvant Therapy in Cancer Treatment

    Science.gov (United States)

    Zhong, P.; Xing, F.; Huang, X.; Zhu, H.; Lo, H. W.; Zhong, X.; Pruitt, S.; Robertson, C.

    2011-09-01

    To broaden the application spectrum of HIFU in cancer therapy, we performed a pilot experiment to evaluate the potential of using HIFU as a neoadjuvant therapy prior to surgery. Mice bearing wild-type B16F10 melanoma inoculated subcutaneously were either untreated (control) or treated by HIFU, CPA-7 or HIFU+CPA-7 before surgical resection of the primary tumor two days after HIFU treatment. The animals were then followed for four weeks or up to the humane endpoint to determine local recurrence, distant metastasis, and survival rate. The results demonstrate that animals treated by HIFU+CPA-7 (which is a small molecule that suppresses STAT3 activity) had a significantly lower recurrence rate, and slower growth of the recurrent tumor, with concomitantly higher survival rate, followed by those treated with CPA-7 and HIFU, respectively. Immunological assays revealed that CPA-7 treatment could significantly lower STAT3, and subsequently, Treg activities. In particular, the combination of HIFU and CPA-7 can induce a much stronger anti-tumor immune response than HIFU or surgery alone, as assessed by CTL and IFN-γ secretion. Overall, our results suggest that HIFU in combination with immunotherapy strategies has the potential to be used as a neoadjuvant therapy to prime the host with a strong anti-tumor immune response before surgical resection of the primary tumor. This multimodality, combinational therapy has the potential to greatly broaden the range of HIFU applications in cancer therapy with lower tumor recurrence and improved survival rate.

  14. Design of a Low-Power VLSI Macrocell for Nonlinear Adaptive Video Noise Reduction

    OpenAIRE

    Fanucci Luca; Saponara Sergio; Terreni Pierangelo

    2004-01-01

    A VLSI macrocell for edge-preserving video noise reduction is proposed in the paper. It is based on a nonlinear rational filter enhanced by a noise estimator for blind and dynamic adaptation of the filtering parameters to the input signal statistics. The VLSI filter features a modular architecture allowing the extension of both mask size and filtering directions. Both spatial and spatiotemporal algorithms are supported. Simulation results with monochrome test videos prove its efficiency for ...

  15. Real-time adaptive filtering of dental drill noise using a digital signal processor

    OpenAIRE

    Kaymak, E; Atherton, MA; Rotter, KRG; Millar, B.

    2006-01-01

    The application of noise reduction methods requires the integration of acoustics engineering and digital signal processing, which is well served by a mechatronic approach as described in this paper. The Normalised Least Mean Square (NLMS) algorithm is implemented on the Texas Instruments TMS320C6713 DSK Digital Signal Processor (DSP) as an adaptive digital filter for dental drill noise. Blocks within the Matlab/Simulink Signal Processing Blockset and the Embedded Target for TI C6000 DSP famil...

  16. Time-Scale and Noise Optimality in Self-Organized Critical Adaptive Networks

    CERN Document Server

    Kuehn, Christian

    2011-01-01

    Recent studies have shown that adaptive networks driven by simple local rules can organize into "critical" global steady states, thereby providing another framework for self-organized criticality (SOC). Here we study SOC in an adaptive network considered first by Bornholdt and Rohlf [PRL, 84(26), p.6114-6117, 2000]. We focus on the important convergence to criticality and discover time-scale and noise optimal behaviour as well as a noise-induced phase transition. Due to the complexity of adaptive networks dynamics we suggest to investigate each effect separately by developing simple models. These models reveal three generically possible low-dimensional dynamical behaviors: time-scale resonance (TR), a simplified version of stochastic resonance - which call steady state stochastic resonance (SSR) - as well as noise-induced phase transitions. Thereby, our study not only opens up new directions for optimality in SOC but also applies to a much wider class of dynamical systems.

  17. Removal of noises from electromagnetic radiation of coal or rock with EEMD-adaptive morphological filter

    Institute of Scientific and Technical Information of China (English)

    CHEN Shi-hai; WANG En-yuan

    2012-01-01

    The electromagnetic radiation (EMR) signal collected by monitoring system during coal or rock dynamic disaster may be interferred easily by electromagnetic noises in mines.The noises have a direct influence on the recognition and analysis of the EMR signal features during the disaster.With the aim of removing these noises,an ensemble empirical mode decomposition (EEMD) adaptive morphological filter was proposed.From the result of the simulation and the experiment,it is shown that the method can restrain the random noise and white Gaussian noise mixed with EMR signal effectively.The filter is highly useful for improving the robustness of the coal or rock dynamic disaster monitoring system.

  18. Noise in adaptive interferometric fiber sensor based on population dynamic grating in erbium-doped fiber.

    Science.gov (United States)

    Stepanov, Serguei; Sánchez, Marcos Plata; Hernández, Eliseo Hernández

    2016-09-10

    Experimental investigations of the main noise sources that limit the sensitivity of the adaptive interferometric all-fiber sensors operating in the communication wavelength region are reported. Adaptive properties (i.e., the autostabilization of an optimal operation point of the interferometer) are enabled by the dynamic population grating recorded in a segment of the erbium-doped fiber (EDF) at milliwatt-scale cw power in the 1480-1560 nm spectral range. The utilized symmetric Sagnac configuration with low light internal reflections ensures reduced sensitivity of the sensor to phase noise of the laser, while intensity noise is reduced to an insignificant level by the balanced detection scheme. It is shown that the fluorescence from the erbium ions, excited by the counterpropagating waves recording the grating, increases the noise level from the fundamental shot noise approximately by a factor of 2-3 only. It is also shown that conventional communication distributed feedback (DFB) semiconductor lasers with megahertz linewidth are not suitable for high-sensitivity applications of such sensors. Because of inevitable backreflections from the output terminal devices (photodiodes, insulators, circulator), the above-mentioned fundamental noise level is increased by 2 orders of magnitude due to high phase noise of the DFB laser. PMID:27661369

  19. Adaptive Noise Cancellation System for Low Frequency Transmission of Sound in Open Fan Aircraft

    Directory of Open Access Journals (Sweden)

    Steven Griffin

    2013-01-01

    Full Text Available This paper describes the use of a structural/acoustic model of a section of a large aircraft to help define the sensor/actuator architecture that was used in a hardware demonstration of adaptive noise cancellation. Disturbances considered were representative of propeller-induced disturbances from an open fan aircraft. Controller on and controller off results from a hardware demonstration on a portion of a large aircraft are also included. The use of the model has facilitated the development of a new testing technique, closely related to modal testing, that can be used to find good structural actuator locations for adaptive noise cancellation.

  20. Adaptive cancellation of light relative intensity noise for fiber optic gyroscope

    Directory of Open Access Journals (Sweden)

    Zhong xiao Ji

    2013-07-01

    Full Text Available In order to reduce the relative intensity noise (RIN in the interferometric signal of the fiber optic gyroscope (FOG, an adaptive noise subtraction method is presented, which aims to overcome to the drawbacks that the fixed delay time and gain of the digital noise subtraction method. The drawbacks will make the performance of FOG to be degraded greatly in the changing environment. In the paper the adaptive noise subtraction system based on the recursive least squares algorithm (RLS is formed in FPGA, in which the interferometric signal is regarded as the signal source, and RIN in the free end of the optical fiber coupler of FOG is looked as the noise reference signal. The two critical parameters that minimum delay time and its varying range result from measuring the minimum and maximum delay times of the interferometric signal in a certain temperature range. The off-line and on-line temperature experimental results verify the capability of adapting to the environmental temperature.

  1. Adaptive Cancellation of Light Relative Intensity Noise for Fiber Optic Gyroscope

    Directory of Open Access Journals (Sweden)

    Zhongxiao Ji

    2013-07-01

    Full Text Available In order to reduce the relative intensity noise (RIN in the interferometric signal of the fiber optic gyroscope (FOG, an adaptive noise subtraction method is presented, which aims to overcome to the drawbacks that the fixed delay time and gain of the digital noise subtraction method. The drawbacks will make the performance of FOG to be degraded greatly in the changing environment. In the paper the adaptive noise subtraction system based on the recursive least squares algorithm (RLS is formed in FPGA, in which the interferometric signal is regarded as the signal source, and RIN in the free end of the optical fiber coupler of FOG is looked as the noise reference signal. The two critical parameters that minimum delay time and its varying range result from measuring the minimum and maximum delay times of the interferometric signal in a certain temperature range. The off-line and on-line temperature experimental results verify the capability of adapting to the environmental temperature.      

  2. Combined MIMO adaptive and decentralized controllers for broadband active noise and vibration control

    NARCIS (Netherlands)

    Berkhoff, A.P.; Wesselink, J.M.

    2011-01-01

    Model errors in multiple-input multiple-output adaptive controllers for reduction of broadband noise and vibrations may lead to unstable systems or increased error signals. In this paper, a combination of high-authority control (HAC) and low-authority control (LAC) is considered for improved perform

  3. Adaptive V/UV Speech Detection Based on Characterization of Background Noise

    Directory of Open Access Journals (Sweden)

    F. Beritelli

    2009-01-01

    Full Text Available The paper presents an adaptive system for Voiced/Unvoiced (V/UV speech detection in the presence of background noise. Genetic algorithms were used to select the features that offer the best V/UV detection according to the output of a background Noise Classifier (NC and a Signal-to-Noise Ratio Estimation (SNRE system. The system was implemented, and the tests performed using the TIMIT speech corpus and its phonetic classification. The results were compared with a nonadaptive classification system and the V/UV detectors adopted by two important speech coding standards: the V/UV detection system in the ETSI ES 202 212 v1.1.2 and the speech classification in the Selectable Mode Vocoder (SMV algorithm. In all cases the proposed adaptive V/UV classifier outperforms the traditional solutions giving an improvement of 25% in very noisy environments.

  4. Transform Domain Robust Variable Step Size Griffiths' Adaptive Algorithm for Noise Cancellation in ECG

    Science.gov (United States)

    Hegde, Veena; Deekshit, Ravishankar; Satyanarayana, P. S.

    2011-12-01

    The electrocardiogram (ECG) is widely used for diagnosis of heart diseases. Good quality of ECG is utilized by physicians for interpretation and identification of physiological and pathological phenomena. However, in real situations, ECG recordings are often corrupted by artifacts or noise. Noise severely limits the utility of the recorded ECG and thus needs to be removed, for better clinical evaluation. In the present paper a new noise cancellation technique is proposed for removal of random noise like muscle artifact from ECG signal. A transform domain robust variable step size Griffiths' LMS algorithm (TVGLMS) is proposed for noise cancellation. For the TVGLMS, the robust variable step size has been achieved by using the Griffiths' gradient which uses cross-correlation between the desired signal contaminated with observation or random noise and the input. The algorithm is discrete cosine transform (DCT) based and uses symmetric property of the signal to represent the signal in frequency domain with lesser number of frequency coefficients when compared to that of discrete Fourier transform (DFT). The algorithm is implemented for adaptive line enhancer (ALE) filter which extracts the ECG signal in a noisy environment using LMS filter adaptation. The proposed algorithm is found to have better convergence error/misadjustment when compared to that of ordinary transform domain LMS (TLMS) algorithm, both in the presence of white/colored observation noise. The reduction in convergence error achieved by the new algorithm with desired signal decomposition is found to be lower than that obtained without decomposition. The experimental results indicate that the proposed method is better than traditional adaptive filter using LMS algorithm in the aspects of retaining geometrical characteristics of ECG signal.

  5. Adaptive Threshold Clipper Combining Receiver for Fast Frequency Hopping Systems during Partial-Band Noise Jamming

    Institute of Scientific and Technical Information of China (English)

    肖立民; 许希斌; 姚彦

    2001-01-01

    Diversity combining technologies are analyzed for fastfrequency-hopping spread spectrum systems during partial-band noise jamming to develop a novel combining receiver called an Adaptive Threshold Clipper Combining Receiver (ATCCR). The optimal clipping level for an ATCCR is analyzed, computed, and compared with several other diversity combining technologies. Since the ATCCR can estimate the power of the jamming and the number of jammed frequency cells to adaptively adjust the clipper's threshold, the system performance using the adaptive threshold clipper combining technique can be greatly improved.

  6. Adaptive correction procedure for TVL1 image deblurring under impulse noise

    Science.gov (United States)

    Bai, Minru; Zhang, Xiongjun; Shao, Qianqian

    2016-08-01

    For the problem of image restoration of observed images corrupted by blur and impulse noise, the widely used TVL1 model may deviate from both the data-acquisition model and the prior model, especially for high noise levels. In order to seek a solution of high recovery quality beyond the reach of the TVL1 model, we propose an adaptive correction procedure for TVL1 image deblurring under impulse noise. Then, a proximal alternating direction method of multipliers (ADMM) is presented to solve the corrected TVL1 model and its convergence is also established under very mild conditions. It is verified by numerical experiments that our proposed approach outperforms the TVL1 model in terms of signal-to-noise ratio (SNR) values and visual quality, especially for high noise levels: it can handle salt-and-pepper noise as high as 90% and random-valued noise as high as 70%. In addition, a comparison with a state-of-the-art method, the two-phase method, demonstrates the superiority of the proposed approach.

  7. Noise-induced interspike interval correlations and spike train regularization in spike-triggered adapting neurons

    CERN Document Server

    Urdapilleta, Eugenio

    2016-01-01

    Spike generation in neurons produces a temporal point process, whose statistics is governed by intrinsic phenomena and the external incoming inputs to be coded. In particular, spike-evoked adaptation currents support a slow temporal process that conditions spiking probability at the present time according to past activity. In this work, we study the statistics of interspike interval correlations arising in such non-renewal spike trains, for a neuron model that reproduces different spike modes in a small adaptation scenario. We found that correlations are stronger as the neuron fires at a particular firing rate, which is defined by the adaptation process. When set in a subthreshold regime, the neuron may sustain this particular firing rate, and thus induce correlations, by noise. Given that, in this regime, interspike intervals are negatively correlated at any lag, this effect surprisingly implies a reduction in the variability of the spike count statistics at a finite noise intensity.

  8. Background noise cancellation of manatee vocalizations using an adaptive line enhancer.

    Science.gov (United States)

    Yan, Zheng; Niezrecki, Christopher; Cattafesta, Louis N; Beusse, Diedrich O

    2006-07-01

    The West Indian manatee (Trichechus manatus latirostris) has become an endangered species partly because of an increase in the number of collisions with boats. A device to alert boaters of the presence of manatees is desired. Previous research has shown that background noise limits the manatee vocalization detection range (which is critical for practical implementation). By improving the signal-to-noise ratio of the measured manatee vocalization signal, it is possible to extend the detection range. The finite impulse response (FIR) structure of the adaptive line enhancer (ALE) can detect and track narrow-band signals buried in broadband noise. In this paper, a constrained infinite impulse response (IIR) ALE, called a feedback ALE (FALE), is implemented to reduce the background noise. In addition, a bandpass filter is used as a baseline for comparison. A library consisting of 100 manatee calls spanning ten different signal categories is used to evaluate the performance of the bandpass filter, FIR-ALE, and FALE. The results show that the FALE is capable of reducing background noise by about 6.0 and 21.4 dB better than that of the FIR-ALE and bandpass filter, respectively, when the signal-to-noise ratio (SNR) of the original manatee call is -5 dB. PMID:16875212

  9. REMOVAL OF HIGH DENSITY IMPULSE NOISE USING MORPHOLOGICAL BASED ADAPTIVE UNSYMMETRICAL TRIMMED MID-POINT FILTER

    Directory of Open Access Journals (Sweden)

    S. Saravanakumar

    2014-01-01

    Full Text Available A Morphological based Adaptive Unsymmetrical Trimmed Mid-Point Filter (MAUTMPF for the restoration of gray scale images corrupted by salt and pepper noise for varying noise densities is proposed in this study. Images corrupted by impulsive noise severely hinder subsequent image processing tasks, such as edge detection, image segmentation, object recognition, etc. Therefore, it is absolutely essential to restore the original image from the corrupted image. The proposed algorithm replaces the corrupted pixel by mid point value out of the retained pixels other than 0’s and 255’s in a 3×3 window. The essential condition for the validity of the window is that at least two pixels in the selected window should be uncorrupted; if not the window size is incremented by 2. The iteration stops when the window size reaches 7. In particular case, when the condition for validity doesn’t hold in 7×7 window then the original 3×3 window is chosen and midpoint of minimum and maximum values of already processed pixels is replaced with the centre pixel. experimental evaluation using MATLAB reveals that our MAUTMPF shows better performance compared to the previous de-noising algorithms in terms of Peak Signal-to-Noise Ratio (PSNR and Mean Square Error (MSE for noise densities up to 90%. The validity of the proposed algorithm is verified by testing it for different gray scale images.

  10. Noise

    Science.gov (United States)

    Noise is all around you, from televisions and radios to lawn mowers and washing machines. Normally, you ... sensitive structures of the inner ear and cause noise-induced hearing loss. More than 30 million Americans ...

  11. An adaptive segment method for smoothing lidar signal based on noise estimation

    Science.gov (United States)

    Wang, Yuzhao; Luo, Pingping

    2014-10-01

    An adaptive segmentation smoothing method (ASSM) is introduced in the paper to smooth the signal and suppress the noise. In the ASSM, the noise is defined as the 3σ of the background signal. An integer number N is defined for finding the changing positions in the signal curve. If the difference of adjacent two points is greater than 3Nσ, the position is recorded as an end point of the smoothing segment. All the end points detected as above are recorded and the curves between them will be smoothed separately. In the traditional method, the end points of the smoothing windows in the signals are fixed. The ASSM creates changing end points in different signals and the smoothing windows could be set adaptively. The windows are always set as the half of the segmentations and then the average smoothing method will be applied in the segmentations. The Iterative process is required for reducing the end-point aberration effect in the average smoothing method and two or three times are enough. In ASSM, the signals are smoothed in the spacial area nor frequent area, that means the frequent disturbance will be avoided. A lidar echo was simulated in the experimental work. The echo was supposed to be created by a space-born lidar (e.g. CALIOP). And white Gaussian noise was added to the echo to act as the random noise resulted from environment and the detector. The novel method, ASSM, was applied to the noisy echo to filter the noise. In the test, N was set to 3 and the Iteration time is two. The results show that, the signal could be smoothed adaptively by the ASSM, but the N and the Iteration time might be optimized when the ASSM is applied in a different lidar.

  12. Audiovisual cues benefit recognition of accented speech in noise but not perceptual adaptation.

    Science.gov (United States)

    Banks, Briony; Gowen, Emma; Munro, Kevin J; Adank, Patti

    2015-01-01

    Perceptual adaptation allows humans to recognize different varieties of accented speech. We investigated whether perceptual adaptation to accented speech is facilitated if listeners can see a speaker's facial and mouth movements. In Study 1, participants listened to sentences in a novel accent and underwent a period of training with audiovisual or audio-only speech cues, presented in quiet or in background noise. A control group also underwent training with visual-only (speech-reading) cues. We observed no significant difference in perceptual adaptation between any of the groups. To address a number of remaining questions, we carried out a second study using a different accent, speaker and experimental design, in which participants listened to sentences in a non-native (Japanese) accent with audiovisual or audio-only cues, without separate training. Participants' eye gaze was recorded to verify that they looked at the speaker's face during audiovisual trials. Recognition accuracy was significantly better for audiovisual than for audio-only stimuli; however, no statistical difference in perceptual adaptation was observed between the two modalities. Furthermore, Bayesian analysis suggested that the data supported the null hypothesis. Our results suggest that although the availability of visual speech cues may be immediately beneficial for recognition of unfamiliar accented speech in noise, it does not improve perceptual adaptation.

  13. Dynamic Adaptive Median Filter (DAMF for Removal of High Density Impulse Noise

    Directory of Open Access Journals (Sweden)

    Punyaban Patel

    2012-10-01

    Full Text Available This paper proposes a novel adaptive filtering scheme to remove impulse noise from images. The scheme replaces the corrupted test pixel with the median value of non-corrupted neighboring pixels selected from a window dynamically. If the number of non-corrupted pixels in the selected window is not sufficient, a window of next higher size is chosen. Thus window size is automatically adapted based on the density of noise in the image as well as the density of corruption local to a window. As a result window size may vary pixel to pixel while filtering. The scheme is simple to implement and do not require multiple iterations. The efficacy of the proposed scheme is evaluated with respect to subjective as well as objective parameters on standard images on various noise densities. Comparative analysis reveals that the proposed scheme has improved performance over other schemes, preferably in high density impulse noise cases. Further, the computational overhead is also less as compared its competent scheme.

  14. A NOISE ADAPTIVE FUZZY EQUALIZATION METHOD FOR PROCESSING SOLAR EXTREME ULTRAVIOLET IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Druckmueller, M., E-mail: druckmuller@fme.vutbr.cz [Institute of Mathematics, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2, 616 69 Brno (Czech Republic)

    2013-08-15

    A new image enhancement tool ideally suited for the visualization of fine structures in extreme ultraviolet images of the corona is presented in this paper. The Noise Adaptive Fuzzy Equalization method is particularly suited for the exceptionally high dynamic range images from the Atmospheric Imaging Assembly instrument on the Solar Dynamics Observatory. This method produces artifact-free images and gives significantly better results than methods based on convolution or Fourier transform which are often used for that purpose.

  15. AN ADAPTIVE OPTIMAL KALMAN FILTER FOR STOCHASTIC VIBRATION CONTROL SYSTEM WITH UNKNOWN NOISE VARIANCES

    Institute of Scientific and Technical Information of China (English)

    Li Shu; Zhuo Jiashou; Ren Qingwen

    2000-01-01

    In this paper, an optimal criterion is presented for adaptive Kalman filter in a control sys tem with unknown variances of stochastic vibration by constructing a function of noise variances and minimizing the function. We solve the model and measure variances by using DFP optimal method to guarantee the results of Kalman filter to be optimized. Finally, the control of vibration can be implemented by LQG method.

  16. Speech perception at positive signal-to-noise ratios using adaptive adjustment of time compression.

    Science.gov (United States)

    Schlueter, Anne; Brand, Thomas; Lemke, Ulrike; Nitzschner, Stefan; Kollmeier, Birger; Holube, Inga

    2015-11-01

    Positive signal-to-noise ratios (SNRs) characterize listening situations most relevant for hearing-impaired listeners in daily life and should therefore be considered when evaluating hearing aid algorithms. For this, a speech-in-noise test was developed and evaluated, in which the background noise is presented at fixed positive SNRs and the speech rate (i.e., the time compression of the speech material) is adaptively adjusted. In total, 29 younger and 12 older normal-hearing, as well as 24 older hearing-impaired listeners took part in repeated measurements. Younger normal-hearing and older hearing-impaired listeners conducted one of two adaptive methods which differed in adaptive procedure and step size. Analysis of the measurements with regard to list length and estimation strategy for thresholds resulted in a practical method measuring the time compression for 50% recognition. This method uses time-compression adjustment and step sizes according to Versfeld and Dreschler [(2002). J. Acoust. Soc. Am. 111, 401-408], with sentence scoring, lists of 30 sentences, and a maximum likelihood method for threshold estimation. Evaluation of the procedure showed that older participants obtained higher test-retest reliability compared to younger participants. Depending on the group of listeners, one or two lists are required for training prior to data collection. PMID:26627804

  17. Adaptive cancellation of geomagnetic background noise for magnetic anomaly detection using coherence

    International Nuclear Information System (INIS)

    Magnetic anomaly detection (MAD) is an effective method for the detection of ferromagnetic targets against background magnetic fields. Currently, the performance of MAD systems is mainly limited by the background geomagnetic noise. Several techniques have been developed to detect target signatures, such as the synchronous reference subtraction (SRS) method. In this paper, we propose an adaptive coherent noise suppression (ACNS) method. The proposed method is capable of evaluating and detecting weak anomaly signals buried in background geomagnetic noise. Tests with real-world recorded magnetic signals show that the ACNS method can excellently remove the background geomagnetic noise by about 21 dB or more in high background geomagnetic field environments. Additionally, as a general form of the SRS method, the ACNS method offers appreciable advantages over the existing algorithms. Compared to the SRS method, the ACNS algorithm can eliminate the false target signals and represents a noise suppressing capability improvement of 6.4 dB. The positive outcomes in terms of intelligibility make this method a potential candidate for application in MAD systems. (paper)

  18. Processing ultrasound backscatter to monitor high-intensity focused ultrasound (HIFU) therapy

    Science.gov (United States)

    Kaczkowski, Peter J.; Anand, Ajay; Bailey, Michael R.

    2005-09-01

    The development of new noninvasive surgical methods such as HIFU for the treatment of cancer and internal bleeding requires simultaneous development of new sensing approaches to guide, monitor, and assess the therapy. Ultrasound imaging using echo amplitude has long been used to map tissue morphology for diagnostic interpretation by the clinician. New quantitative ultrasonic methods that rely on amplitude and phase processing for tissue characterization are being developed for monitoring of ablative therapy. We have been developing the use of full wave ultrasound backscattering for real-time temperature estimation, and to image changes in tissue backscatter spectrum as therapy progresses. Both approaches rely on differential processing of the backscatter signal in time, and precise measurement of phase differences. Noise and artifacts from motion and nonstationary speckle statistics are addressed by constraining inversions for tissue parameters with physical models. We present results of HIFU experiments with static point and scanned HIFU exposures in which temperature rise can be accurately mapped using a new heat transfer equation (HTE) model-constrained inverse approach. We also present results of a recently developed spectral imaging method that elucidates microbubble-mediated nonlinearity not visible as a change in backscatter amplitude. [Work supported by Army MRMC.

  19. Development of HIFU Treatment for Lower Extremity Varicose Veins

    Science.gov (United States)

    Senoo, Naohiko; Ushijima, Hiroyuki; Suzuki, Jun; Yoshinaka, Kiyoshi; Deguchi, Juno; Takagi, Shu; Miyata, Tetsuro; Matsumoto, Yoichiro

    2011-09-01

    High-intensity focused ultrasound (HIFU) has recently been developed as a noninvasive therapeutic method. In our study, a novel noninvasive therapy with HIFU was proposed for occlusion of lower extremity varicose veins. The temperature increase caused by HIFU is used to occlude varicose veins. Occluded veins became fibrotic, resulting in complete recovery. Our final goal is the medical application of HIFU treatment for varicose veins. In this study, we attempted to occlude the veins of rabbits. Prior to venous occlusion experiments, the area heated by HIFU was investigated using bovine serum albumin (BSA) gel, which denatures at >70 °C. The results indicate that the size of the heated area mainly depends on intensity at the focal point and the exposure time. A tendency was also seen for the heated area to extend toward the transducer with increasing exposure time. In animal experiments, skin burns during HIFU exposure represented a critical problem. We therefore examined the safe range of HIFU intensities in abdominal exposure experiments before conducting venous occlusion experiments. The ultrasound frequency was 1.7 MHz. Intensity at the focal point was 900 W/cm2, and the exposure time was 20 s. Rabbits underwent chemical depilation and echo gel was applied to the exposed skin to fill the boundary gap. Target veins were compressed during HIFU exposure to avoid thermal dissipation, and hyaluronan water solution was injected between the veins and skin to maintain the distance between the skin and veins at ≥5 mm. Veins were then exposed to HIFU and occluded. The capability of HIFU treatment to occlude lower extremity varicose veins was verified by the present study.

  20. Adaptive control of stochastic Hammerstein-Wiener nonlinear systems with measurement noise

    Science.gov (United States)

    Zhang, Bi; Mao, Zhizhong

    2016-01-01

    This paper deals with the adaptive control of a class of stochastic Hammerstein-Wiener nonlinear systems with measurement noise. Despite the fundamental progress achieved so far, a general theory framework about adaptive control of Hammerstein-Wiener models is still absent. Such situation is mainly due to the lack of an appropriate parameterisation model. To this end, this paper presents a novel parameterisation model that is to replace unmeasurable internal variables with their estimations. Then, the adaptive control algorithm to be applied is derived on the basis of self-tuning control. In addition, due to the use of the internal variable estimations, the stability and convergence properties are different from the self-tuning control. Our aim, in theoretical analysis, is to discover what limitations are in using the estimations instead of the true values in a control algorithm. Representative numerical examples are given and the simulation results verify the theoretical analysis.

  1. Three-dimensional anisotropic adaptive filtering of projection data for noise reduction in cone beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Andreas; Wigstroem, Lars; Hofmann, Hannes G.; Hornegger, Joachim; Zhu Lei; Strobel, Norbert; Fahrig, Rebecca [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Department of Radiology, Stanford University, Stanford, California 94305 (United States) and Center for Medical Image Science and Visualization, Linkoeping University, Linkoeping (Sweden); Pattern Recognition Laboratory, Department of Computer Science, Friedrich-Alexander University of Erlangen-Nuremberg, 91054, Erlangen (Germany); Nuclear and Radiological Engineering and Medical Physics Programs, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Siemens AG Healthcare, Forchheim 91301 (Germany); Department of Radiology, Stanford University, Stanford, California 94305 (United States)

    2011-11-15

    Purpose: The combination of quickly rotating C-arm gantry with digital flat panel has enabled the acquisition of three-dimensional data (3D) in the interventional suite. However, image quality is still somewhat limited since the hardware has not been optimized for CT imaging. Adaptive anisotropic filtering has the ability to improve image quality by reducing the noise level and therewith the radiation dose without introducing noticeable blurring. By applying the filtering prior to 3D reconstruction, noise-induced streak artifacts are reduced as compared to processing in the image domain. Methods: 3D anisotropic adaptive filtering was used to process an ensemble of 2D x-ray views acquired along a circular trajectory around an object. After arranging the input data into a 3D space (2D projections + angle), the orientation of structures was estimated using a set of differently oriented filters. The resulting tensor representation of local orientation was utilized to control the anisotropic filtering. Low-pass filtering is applied only along structures to maintain high spatial frequency components perpendicular to these. The evaluation of the proposed algorithm includes numerical simulations, phantom experiments, and in-vivo data which were acquired using an AXIOM Artis dTA C-arm system (Siemens AG, Healthcare Sector, Forchheim, Germany). Spatial resolution and noise levels were compared with and without adaptive filtering. A human observer study was carried out to evaluate low-contrast detectability. Results: The adaptive anisotropic filtering algorithm was found to significantly improve low-contrast detectability by reducing the noise level by half (reduction of the standard deviation in certain areas from 74 to 30 HU). Virtually no degradation of high contrast spatial resolution was observed in the modulation transfer function (MTF) analysis. Although the algorithm is computationally intensive, hardware acceleration using Nvidia's CUDA Interface provided an 8

  2. High-Intensity Focused Ultrasound (HIFU) in Localized Prostate Cancer Treatment

    OpenAIRE

    Alkhorayef, Mohammed; Mahmoud, Mustafa Z.; Alzimami, Khalid S.; Sulieman, Abdelmoneim; Fagiri, Maram A.

    2015-01-01

    Summary Background High-intensity focused ultrasound (HIFU) applies high-intensity focused ultrasound energy to locally heat and destroy diseased or damaged tissue through ablation. This study intended to review HIFU to explain the fundamentals of HIFU, evaluate the evidence concerning the role of HIFU in the treatment of prostate cancer (PC), review the technologies used to perform HIFU and the published clinical literature regarding the procedure as a primary treatment for PC. Material/Meth...

  3. Optimal and Adaptive Virtual Unidirectional Sound Source in Active Noise Control

    Directory of Open Access Journals (Sweden)

    Dariusz Bismor

    2008-01-01

    Full Text Available One of the problems concerned with active noise control is the existence of acoustical feedback between the control value (“active” loudspeaker output and the reference signal. Various experiments show that such feedback can seriously decrease effects of attenuation or even make the whole ANC system unstable. This paper presents a detailed analysis of one of possible approaches allowing to deal with acoustical feedback, namely, virtual unidirectional sound source. With this method, two loudspeakers are used together with control algorithm assuring that the combined behaviour of the pair makes virtual propagation of sound only in one direction. Two different designs are presented for the application of active noise control in an acoustic duct: analytical (leading to fixed controller and adaptive. The algorithm effectiveness in simulations and real experiments for both solutions is showed, discussed, and compared.

  4. A Split-and-Merge-Based Uterine Fibroid Ultrasound Image Segmentation Method in HIFU Therapy.

    Directory of Open Access Journals (Sweden)

    Menglong Xu

    Full Text Available High-intensity focused ultrasound (HIFU therapy has been used to treat uterine fibroids widely and successfully. Uterine fibroid segmentation plays an important role in positioning the target region for HIFU therapy. Presently, it is completed by physicians manually, reducing the efficiency of therapy. Thus, computer-aided segmentation of uterine fibroids benefits the improvement of therapy efficiency. Recently, most computer-aided ultrasound segmentation methods have been based on the framework of contour evolution, such as snakes and level sets. These methods can achieve good performance, although they need an initial contour that influences segmentation results. It is difficult to obtain the initial contour automatically; thus, the initial contour is always obtained manually in many segmentation methods. A split-and-merge-based uterine fibroid segmentation method, which needs no initial contour to ensure less manual intervention, is proposed in this paper. The method first splits the image into many small homogeneous regions called superpixels. A new feature representation method based on texture histogram is employed to characterize each superpixel. Next, the superpixels are merged according to their similarities, which are measured by integrating their Quadratic-Chi texture histogram distances with their space adjacency. Multi-way Ncut is used as the merging criterion, and an adaptive scheme is incorporated to decrease manual intervention further. The method is implemented using Matlab on a personal computer (PC platform with Intel Pentium Dual-Core CPU E5700. The method is validated on forty-two ultrasound images acquired from HIFU therapy. The average running time is 9.54 s. Statistical results showed that SI reaches a value as high as 87.58%, and normHD is 5.18% on average. It has been demonstrated that the proposed method is appropriate for segmentation of uterine fibroids in HIFU pre-treatment imaging and planning.

  5. Noise robust automatic speech recognition with adaptive quantile based noise estimation and speech band emphasizing filter bank

    DEFF Research Database (Denmark)

    Bonde, Casper Stork; Graversen, Carina; Gregersen, Andreas Gregers;

    2005-01-01

    to the appearance of the speech signal which require noise robust voice activity detection and assumptions of stationary noise. However, both of these requirements are often not met and it is therefore of particular interest to investigate methods like the Quantile Based Noise Estimation (QBNE) mehtod which...

  6. Adaptive Helmholtz resonators and passive vibration absorbers for cylinder interior noise control

    Science.gov (United States)

    Estève, Simon J.; Johnson, Marty E.

    2005-12-01

    This paper presents an adaptive-passive solution to control the broadband sound transmission into rocket payload fairings. The treatment is composed of passive distributed vibration absorbers (DVAs) and adaptive Helmholtz resonators (HR). Both the frequency domain and time-domain model of a simply supported cylinder excited by an external plane wave are developed. To tune vibration absorbers to tonal excitation, a tuning strategy, based on the phase information between the velocity of the absorber mass and the velocity of the host structure is used here in a new fashion to tune resonators to peaks in the broadband acoustic spectrum of a cavity. This tuning law, called the dot-product method, only uses two microphone signals local to each HR, which allows the adaptive Helmholtz resonator (AHR) to be manufactured as an autonomous device with power supply, sensor, actuator and controller integrated. Numerical simulations corresponding to a 2.8 m long 2.5 m diameter composite cylinder prototype demonstrate that, as long as the structure modes, which strongly couple to the acoustic cavity, are damped with a DVA treatment, the dot-product method tune multiple HRs to a near-optimal solution over a broad frequency range (40-160 Hz). An adaptive HR prototype with variable opening is built and characterized. Experiments conducted on the cylinder prototype with eight AHRs demonstrate the ability of resonators adapted with the dot-product method to converge to near-optimal noise attenuation in a frequency band including multiple resonances.

  7. PASSIVE CAVITATION DETECTION DURING PULSED HIFU EXPOSURES OF EX VIVO TISSUES AND IN VIVO MOUSE PANCREATIC TUMORS

    Science.gov (United States)

    Li, Tong; Chen, Hong; Khokhlova, Tatiana; Wang, Yak-Nam; Kreider, Wayne; He, Xuemei; Hwang, Joo Ha

    2014-01-01

    Pulsed high-intensity focused ultrasound (pHIFU) has been demonstrated to enhance vascular permeability, disrupt tumor barriers and enhance drug penetration into tumor tissue through acoustic cavitation. Monitoring of cavitation activity during pHIFU treatments and knowing the ultrasound pressure levels sufficient to reliably induce cavitation in a given tissue are therefore very important. Here, three metrics of cavitation activity induced by pHIFU and evaluated by confocal passive cavitation detection were introduced: cavitation probability, cavitation persistence and the level of the broadband acoustic emissions. These metrics were used to characterize cavitation activity in several ex vivo tissue types (bovine tongue and liver and porcine adipose tissue and kidney) and gel phantoms (polyacrylamide and agarose) at varying peak-rarefactional focal pressures (1–12 MPa) during the following pHIFU protocol: frequency 1.1 MHz, pulse duration 1 ms, pulse repetition frequency 1 Hz. To evaluate the relevance of the measurements in ex vivo tissue, cavitation metrics were also investigated and compared in the ex vivo and in vivo murine pancreatic tumors that develop spontaneously in transgenic KPC mice and closely recapitulate human disease in their morphology. The cavitation threshold, defined at 50 % cavitation probability, was found to vary broadly among the investigated tissues (within 2.5–10 MPa), depending mostly on the water-lipid ratio that characterizes the tissue composition. Cavitation persistence and the intensity of broadband emissions depended both on tissue structure and lipid concentration. Both the cavitation threshold and broadband noise emission level were similar between ex vivo and in vivo pancreatic tumor tissue. The largest difference between in vivo and ex vivo settings was found in the pattern of cavitation occurrence throughout pHIFU exposure: it was sporadic in vivo, but ex vivo it decreased rapidly and stopped over the first few pulses

  8. Measurements of HIFU-induced Lesions in BSA Gel Phantoms for HIFU Treatment of Varicose Veins of Lower Extremity

    Science.gov (United States)

    Ushijima, Hiroyuki; Senoo, Naohiko; Suzuki, Jun; Ichiyanagi, Mitsuhisa; Yoshinaka, Kiyoshi; Deguchi, Juno; Takagi, Shu; Miyata, Tetsuro; Matsumoto, Yoichiro

    2011-09-01

    HIFU treatment has been developed for various diseases because of its minimal invasiveness, and we are now developing a HIFU treatment for varicose veins of the lower extremity. Previous studies have succeeded in occluding rabbit's veins with HIFU, but the success rate was low (about 10%). Failures were mainly caused by skin burns. When the heating lesion comes close to skin, the absorbed ultrasound energy may cause skin burns. Therefore, it is necessary to study the relationships between HIFU lesions and skin burns to improve the success rate. To visualize heating lesions from HIFU, we used tissue-mimicking BSA gel phantoms. We tried various concentrations of BSA in gels, and determined 14% BSA as the most suitable for phantoms for experiments. The attenuation coefficient of the gel was 0.73 dB/cm, and the denaturation temperature was 70 °C. We put the BSA gel phantom in a water tank in which the temperature was kept at 39 °C, and used HIFU exposures at various intensities and irradiation times. After irradiation, we measured the sizes and positions of HIFU-induced lesions, and the results indicate that the sizes of lesion become larger when the intensitiy rises or irradiation time becomes longer. Furthermore, when the intensity rises and irradiation time becomes longer, the heating lesions move closer to upper surface of the gel, which means skin easily gets burned. Thus we have investigated relationships between HIFU parameters and heated lesions that can be used for further research into HIFU treatment of varicose veins of the lower extremity.

  9. Speech Enhancement, Gain, and Noise Spectrum Adaptation Using Approximate Bayesian Estimation.

    Science.gov (United States)

    Hao, Jiucang; Attias, Hagai; Nagarajan, Srikantan; Lee, Te-Won; Sejnowski, Terrence J

    2009-01-01

    This paper presents a new approximate Bayesian estimator for enhancing a noisy speech signal. The speech model is assumed to be a Gaussian mixture model (GMM) in the log-spectral domain. This is in contrast to most current models in frequency domain. Exact signal estimation is a computationally intractable problem. We derive three approximations to enhance the efficiency of signal estimation. The Gaussian approximation transforms the log-spectral domain GMM into the frequency domain using minimal Kullback-Leiber (KL)-divergency criterion. The frequency domain Laplace method computes the maximum a posteriori (MAP) estimator for the spectral amplitude. Correspondingly, the log-spectral domain Laplace method computes the MAP estimator for the log-spectral amplitude. Further, the gain and noise spectrum adaptation are implemented using the expectation-maximization (EM) algorithm within the GMM under Gaussian approximation. The proposed algorithms are evaluated by applying them to enhance the speeches corrupted by the speech-shaped noise (SSN). The experimental results demonstrate that the proposed algorithms offer improved signal-to-noise ratio, lower word recognition error rate, and less spectral distortion. PMID:20428253

  10. Neural Mechanisms Behind Identification of Leptokurtic Noise and Adaptive Behavioral Response.

    Science.gov (United States)

    d'Acremont, Mathieu; Bossaerts, Peter

    2016-04-01

    Large-scale human interaction through, for example, financial markets causes ceaseless random changes in outcome variability, producing frequent and salient outliers that render the outcome distribution more peaked than the Gaussian distribution, and with longer tails. Here, we study how humans cope with this evolutionary novel leptokurtic noise, focusing on the neurobiological mechanisms that allow the brain, 1) to recognize the outliers as noise and 2) to regulate the control necessary for adaptive response. We used functional magnetic resonance imaging, while participants tracked a target whose movements were affected by leptokurtic noise. After initial overreaction and insufficient subsequent correction, participants improved performance significantly. Yet, persistently long reaction times pointed to continued need for vigilance and control. We ran a contrasting treatment where outliers reflected permanent moves of the target, as in traditional mean-shift paradigms. Importantly, outliers were equally frequent and salient. There, control was superior and reaction time was faster. We present a novel reinforcement learning model that fits observed choices better than the Bayes-optimal model. Only anterior insula discriminated between the 2 types of outliers. In both treatments, outliers initially activated an extensive bottom-up attention and belief network, followed by sustained engagement of the fronto-parietal control network.

  11. PREVENTION OF DYSURIA AFTER HIFU THERAPY FOR PROSTATE CANCER

    OpenAIRE

    A. Yu. Shestaev; V. V. Protoshchak; L. M. Sinelnikov; V. A. Kardinalova; R. A. Yeloev

    2014-01-01

    Objective: to identify factors for the development of dysuria and its prevention in patients with prostate cancer (PC) after high-intensity focused ultrasound (HIFU) therapy.Subjects and methods. In September 2008 to June 2013, the Clinic of Urology, S.M. Kirov Military Medical Academy, treated 98 patients, by performing HIFU sessions on an Ablatherm apparatus (EDAP, France). All the patients underwent transurethral resection of the prostate (TURP) to reduce the volume of the ablated tissue. ...

  12. PREVENTION OF DYSURIA AFTER HIFU THERAPY FOR PROSTATE CANCER

    Directory of Open Access Journals (Sweden)

    A. Yu. Shestaev

    2014-07-01

    Full Text Available Objective: to identify factors for the development of dysuria and its prevention in patients with prostate cancer (PC after high-intensity focused ultrasound (HIFU therapy.Subjects and methods. In September 2008 to June 2013, the Clinic of Urology, S.M. Kirov Military Medical Academy, treated 98 patients, by performing HIFU sessions on an Ablatherm apparatus (EDAP, France. All the patients underwent transurethral resection of the prostate (TURP to reduce the volume of the ablated tissue. The patients were divided into 2 groups: 1 29 patients underwent TURP 3 days before HIFU therapy; 2 69 did this 1 month before major surgery. Each group was divided into 2 subgroups: 1 after ultrasound ablation, a urethral catheter was inserted for 10 days; 2 epicystostoma was applied, followed by its overlapping on day 3 postablation and spontaneous urination. The postoperative incidence of dysuria was estimated from subjective (complaints, voiding diary, and Inter-national Prostate Symptom Score and objective (uroflowmetry, small pelvic ultrasonography with determination of residual urine volume criteria.Results. In the patients who had undergone TURP one month before HIFU therapy, grades I–II urinary incontinence and urethral pros-tatic stricture occurred much less infrequently than in those who had undergone this maneuver 3 days prior to major surgery. Urinary in-continence and urethral prostatic stricture occurred 2-fold more frequently after TURP being carried out 3 days before HIFU therapy than after the urethral catheter being inserted. TURP performed one month before HIFU therapy showed no great difference in the incidence complications regardless of the type of bladder drainage.Conclusion. The short interval between TURP and HIFU therapy for PC increases the risk of postoperative dysuric events. The optimal time to perform TURP prior to HIFU therapy is 1 month.

  13. PREVENTION OF DYSURIA AFTER HIFU THERAPY FOR PROSTATE CANCER

    Directory of Open Access Journals (Sweden)

    A. Yu. Shestaev

    2014-01-01

    Full Text Available Objective: to identify factors for the development of dysuria and its prevention in patients with prostate cancer (PC after high-intensity focused ultrasound (HIFU therapy.Subjects and methods. In September 2008 to June 2013, the Clinic of Urology, S.M. Kirov Military Medical Academy, treated 98 patients, by performing HIFU sessions on an Ablatherm apparatus (EDAP, France. All the patients underwent transurethral resection of the prostate (TURP to reduce the volume of the ablated tissue. The patients were divided into 2 groups: 1 29 patients underwent TURP 3 days before HIFU therapy; 2 69 did this 1 month before major surgery. Each group was divided into 2 subgroups: 1 after ultrasound ablation, a urethral catheter was inserted for 10 days; 2 epicystostoma was applied, followed by its overlapping on day 3 postablation and spontaneous urination. The postoperative incidence of dysuria was estimated from subjective (complaints, voiding diary, and Inter-national Prostate Symptom Score and objective (uroflowmetry, small pelvic ultrasonography with determination of residual urine volume criteria.Results. In the patients who had undergone TURP one month before HIFU therapy, grades I–II urinary incontinence and urethral pros-tatic stricture occurred much less infrequently than in those who had undergone this maneuver 3 days prior to major surgery. Urinary in-continence and urethral prostatic stricture occurred 2-fold more frequently after TURP being carried out 3 days before HIFU therapy than after the urethral catheter being inserted. TURP performed one month before HIFU therapy showed no great difference in the incidence complications regardless of the type of bladder drainage.Conclusion. The short interval between TURP and HIFU therapy for PC increases the risk of postoperative dysuric events. The optimal time to perform TURP prior to HIFU therapy is 1 month.

  14. Rapid HIFU autofocusing using the entire MR-ARFI image

    Energy Technology Data Exchange (ETDEWEB)

    Grissom, William A.; Kaye, Elena; Pauly, Kim Butts; Zur, Yuval; Yeo, Desmond; Medan, Yoav; Davis, Cynthia [Biomedical Engineering, Vanderbilt University, Nashville, Tennessee (United States); Electrical Engineering, Stanford University, Stanford, California (United States); Radiology, Stanford University, Stanford, California (United States); GE Healthcare, Haifa (Israel); GE Global Research, Niskayuna, New York (United States); Biomedical Engineering, Technion IIT, Haifa (Israel); GE Global Research, Niskayuna, New York (United States)

    2012-11-28

    Phase aberrations and attenuations caused by bone can defocus HIFU in the brain and organs behind the ribcage. To refocus the beam, MR-ARFI can be used to measure tissue displacements created by each element in the transducer, and optimize driving signal delays and amplitudes. We introduce a new MR-ARFI-based autofocusing method that requires many fewer image acquisitions than current methods. The method is validated in simulations of bone and brain HIFU transducers, and compared to a conventional method.

  15. Robust Adaptive Kalman Filtering based on Qusi-Accurate Detection Method and Plant Noise Variance-Covariance Matrix Tuning

    Science.gov (United States)

    Luo, xiaowen; wang, Haitao

    2015-04-01

    In this paper, an algorithm was proposed that tunes both the kinematic and measurement noise variance-covariance (VCV) matrices to produce a more robust and adaptive Kalman filter. The proposed algorithm simultaneously considers both observation outliers and abrupt changes. This algorithm may be divided into two basic parts: 1) robust estimation, from which the position components of the filtering estimates and the equivalent weight factor matrix can be obtained; 2) adaptive estimation, from which the adaptive kinematic noise VCV tuning matrix is calculated. And then, all of the predicted states are adaptively updated. An example was used to demonstrate the efficiency of the new algorithm by processing a set of kinematic GPS data received from a rover mounted on an airplane. The processing results are found to be very satisfactory. The observation outliers and abrupt changes are detected and dealt with accordingly. The detailed calculation procedure for the adaptive VCV tuning matrix is also described.

  16. Development of adaptive IIR filtered-e LMS algorithm for active noise control

    Institute of Scientific and Technical Information of China (English)

    SUN Xu; MENG Guang; TENG Pengxiao; CHEN Duanshi

    2003-01-01

    Compared to finite impulse response (FIR) filters, infinite impulse response (IIR)filters can match the system better with much fewer coefficients, and hence the computationload is saved and the performance improves. Therefore, it is attractive to use IIR filters insteadof FIR filters in active noise control (ANC). However, filtered-U LMS (FULMS) algorithm, theIIR filter-based algorithm commonly used so far cannot ensure global convergence. A new IIRfilter based adaptive algorithm, which can ensure global convergence with computation loadonly slightly increasing, is proposed in this paper. The new algorithm is called as filtered-eLMS algorithm since the error signal of which need to be filtered. Simulation results show thatthe FELMS algorithm presents better performance than the FULMS algorithm.

  17. Adaptive RSOV filter using the FELMS algorithm for nonlinear active noise control systems

    Science.gov (United States)

    Zhao, Haiquan; Zeng, Xiangping; He, Zhengyou; Li, Tianrui

    2013-01-01

    This paper presents a recursive second-order Volterra (RSOV) filter to solve the problems of signal saturation and other nonlinear distortions that occur in nonlinear active noise control systems (NANC) used for actual applications. Since this nonlinear filter based on an infinite impulse response (IIR) filter structure can model higher than second-order and third-order nonlinearities for systems where the nonlinearities are harmonically related, the RSOV filter is more effective in NANC systems with either a linear secondary path (LSP) or a nonlinear secondary path (NSP). Simulation results clearly show that the RSOV adaptive filter using the multichannel structure filtered-error least mean square (FELMS) algorithm can further greatly reduce the computational burdens and is more suitable to eliminate nonlinear distortions in NANC systems than a SOV filter, a bilinear filter and a third-order Volterra (TOV) filter.

  18. Noise correlation-based adaptive polarimetric image representation for contrast enhancement of a polarized beacon in fog

    Science.gov (United States)

    Panigrahi, Swapnesh; Fade, Julien; Alouini, Mehdi

    2015-10-01

    We show the use of a simplified snapshot polarimetric camera along with an adaptive image processing for optimal detection of a polarized light beacon through fog. The adaptive representation is derived using theoretical noise analysis of the data at hand and is shown to be optimal in the Maximum likelihood sense. We report that the contrast enhancing optimal representation that depends on the background noise correlation differs in general from standard representations like polarimetric difference image or polarization filtered image. Lastly, we discuss a detection strategy to reduce the false positive counts.

  19. Improvement in DMSA imaging using adaptive noise reduction: an ROC analysis.

    Science.gov (United States)

    Lorimer, Lisa; Gemmell, Howard G; Sharp, Peter F; McKiddie, Fergus I; Staff, Roger T

    2012-11-01

    Dimercaptosuccinic acid imaging is the 'gold standard' for the detection of cortical defects and diagnosis of scarring of the kidneys. The Siemens planar processing package, which implements adaptive noise reduction using the Pixon algorithm, is designed to allow a reduction in image noise, enabling improved image quality and reduced acquisition time/injected activity. This study aimed to establish the level of improvement in image quality achievable using this algorithm. Images were acquired of a phantom simulating a single kidney with a range of defects of varying sizes, positions and contrasts. These images were processed using the Pixon processing software and shown to 12 observers (six experienced and six novices) who were asked to rate the images on a six-point scale depending on their confidence that a defect was present. The data were analysed using a receiver operating characteristic approach. Results showed that processed images significantly improved the performance of the experienced observers in terms of their sensitivity and specificity. Although novice observers showed significant increase in sensitivity when using the software, a significant decrease in specificity was also seen. This study concludes that the Pixon software can be used to improve the assessment of cortical defects in dimercaptosuccinic acid imaging by suitably trained observers.

  20. Histopathological changes associated with high intensity focused ultrasound (HIFU) treatment for localised adenocarcinoma of the prostate

    OpenAIRE

    van Leenders, G J L H; Beerlage, H; Ruijter, E.; de la Rosette, J J M C H; van de Kaa, C A

    2000-01-01

    Aims—Investigation of the histopathological changes in prostatectomy specimens of patients with prostate cancer after high intensity focused ultrasound (HIFU) and identification of immunohistochemical markers for tissue damage after HIFU treatment.

  1. Usefulness of noise adaptive non-linear Gaussian filter in FDG-PET study

    International Nuclear Information System (INIS)

    In positron emission tomography (PET) studies, shortening transmission (TR) scan time can improve patient comfort and increase scanner throughput. However, PET images from short TR scans may be degraded due to the statistical noise included in the TR image. The purpose of this study was to apply non-linear Gaussian (NLG) and noise adaptive NLG (ANLG) filters to TR images, and to evaluate the extent of noise reduction by the ANLG filter in comparison with that by the NLG filter using phantom and clinical studies. In phantom studies, pool phantoms of various diameters and injected doses of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) were used and the coefficients of variation (CVs) of the counts in the TR images processed with the NLG and ANLG filters were compared. In clinical studies, two normal volunteers and 13 patients with tumors were studied. In volunteer studies, the CV values in the liver were compared. In patient studies, the standardized uptake values (SUVs) of tumors in the emission images were obtained after processing the TR images using the NLG and ANLG filters. In phantom studies, the CV values in the TR images processed with the ANLG filter were smaller than those in the images processed with the NLG filter. When using the ANLG filter, their dependency on the phantom size, injected dose of FDG and TR scan time was smaller than when using the NLG filter. In volunteer studies, the CV values in the images processed with the ANLG filter were smaller than those in the images processed with the NLG filter, and were almost constant regardless of the TR scan time. In patient studies, there was an excellent correlation between the SUVs obtained from the images with a TR scan time of 7 min processed with the NLG filter (x) and those obtained from the images with a TR scan time of 4 min processed with the ANLG filter (y) (r=0.995, y=1.034x-0.075). Our results suggest that the ANLG filter is effective and useful for noise reduction in TR images and shortening TR scan

  2. Combination of the transurethral resection and prostate HIFU ablation at treatment of the localized cancer

    OpenAIRE

    Popkov V.M.; Fomkin R.N.; Blyumberg B.l.; Shatylko T.V.; Sedova L.N.; Abramova E.P.

    2014-01-01

    Research objective: to estimate results of treatment of patients with the localized form of a cancer of a prostate at a combination of a transurethral resection (TURP) and HIFU of an ablation. Objects and research methods: From February, 2009 to February, 2014 of 100 patients with the localized form of a cancer of a prostate were selected for research: 26 patients were included into HIFU and 74 group in group of the combined treatment (TURP+HIFU). Selection criteria for HIFU ablation were ...

  3. High-Intensity Focused Ultrasound (HIFU) in Localized Prostate Cancer Treatment

    International Nuclear Information System (INIS)

    High-intensity focused ultrasound (HIFU) applies high-intensity focused ultrasound energy to locally heat and destroy diseased or damaged tissue through ablation. This study intended to review HIFU to explain the fundamentals of HIFU, evaluate the evidence concerning the role of HIFU in the treatment of prostate cancer (PC), review the technologies used to perform HIFU and the published clinical literature regarding the procedure as a primary treatment for PC. Studies addressing HIFU in localized PC were identified in a search of internet scientific databases. The analysis of outcomes was limited to journal articles written in English and published between 2000 and 2013. HIFU is a non-invasive approach that uses a precisely delivered ultrasound energy to achieve tumor cell necrosis without radiation or surgical excision. In current urological oncology, HIFU is used clinically in the treatment of PC. Clinical research on HIFU therapy for localized PC began in the 1990s, and the majority of PC patients were treated with the Ablatherm device. HIFU treatment for localized PC can be considered as an alternative minimally invasive therapeutic modality for patients who are not candidates for radical prostatectomy. Patients with lower pre-HIFU PSA level and favourable pathologic Gleason score seem to present better oncologic outcomes. Future advances in technology and safety will undoubtedly expand the HIFU role in this indication as more of patient series are published, with a longer follow-up period

  4. Feasibility of monitoring HIFU prostate cancer therapy using elastography

    Science.gov (United States)

    Souchon, Remi; Chapelon, Jean Y.; Bertrand, Michel J.; Kallel, Faouzi; Ophir, Jonathan

    2001-05-01

    The objective of this study is to investigate the feasibility of elastographic monitoring of High Intensity Focused Ultrasound (HIFU) therapy of prostate cancer. Elastography is an imaging technique based on strain estimation in soft tissues under quasi-static compression. Since pathological tissues and HIFU-induced lesions exhibit different elastic properties than normal tissues, elastography is potentially able to achieve these goals. An ultrasound scanner was connected to a PC to acquire RF images. This setup is compatible with a HIFU device used for prostate cancer therapy by transrectal route. The therapy transducer and the biplane-imaging probe are covered with a balloon filled with a coupling liquid. Compression of the prostate is applied by inflating the balloon, while imaging sector scans of the prostate. In-vivo elastograms of the prostate were acquired before HIFU treatment. Problems inherent to in-vivo acquisitions are reported, such as undesired tangential displacements during the radial compression. This study shows the potential for in-vivo elastogram acquisition of HIFU-induced lesions in the human prostate.

  5. Prostate cancer treated with HIFU: A 10-year experience

    Science.gov (United States)

    Chapelon, Jean-Yves; Curiel, Laura; Gelet, Albert

    2001-05-01

    Objectives: To evaluate our overall experience in HIFU in the prostate cancer application, for its two main indications: as a primary care and as a salvage therapy after radiation. Material and method: Group 1: patients treated with HIFU as primary care for localized prostate cancer, with a baseline PSA level lower than 30 ng/ml, and with at least 1 year of follow-up were included in this analysis. Group 2: patients with a local recurrence after radiation. They were all treated using the Ablatherm HIFU device (EDAP S.A., France). Results: Group 1: n=242 patients. The mean nadir PSA was 0.63 sd 1.30 ng/ml, and further follow-up evidenced a 81% negative biopsy rate. These results are influenced by the usual prognostic factors (clinical stage, baseline PSA, Gleason score), and, as for the other treatment option, the nadir allows prediction of the patient outcome. Group 2: n=71 patients. After HIFU treatment, 80% of the patients presented negative biopsies, and 61% had a nadir PSA level lower than 0.5 ng/ml, obtained within 3 months. No rectal injury occurred since the use of specific parameters. Conclusion: Transrectal HIFU is a valuable option for prostate cancer, for primary care as well as for salvage therapy.

  6. An environment-adaptive management algorithm for hearing-support devices incorporating listening situation and noise type classifiers.

    Science.gov (United States)

    Yook, Sunhyun; Nam, Kyoung Won; Kim, Heepyung; Hong, Sung Hwa; Jang, Dong Pyo; Kim, In Young

    2015-04-01

    In order to provide more consistent sound intelligibility for the hearing-impaired person, regardless of environment, it is necessary to adjust the setting of the hearing-support (HS) device to accommodate various environmental circumstances. In this study, a fully automatic HS device management algorithm that can adapt to various environmental situations is proposed; it is composed of a listening-situation classifier, a noise-type classifier, an adaptive noise-reduction algorithm, and a management algorithm that can selectively turn on/off one or more of the three basic algorithms-beamforming, noise-reduction, and feedback cancellation-and can also adjust internal gains and parameters of the wide-dynamic-range compression (WDRC) and noise-reduction (NR) algorithms in accordance with variations in environmental situations. Experimental results demonstrated that the implemented algorithms can classify both listening situation and ambient noise type situations with high accuracies (92.8-96.4% and 90.9-99.4%, respectively), and the gains and parameters of the WDRC and NR algorithms were successfully adjusted according to variations in environmental situation. The average values of signal-to-noise ratio (SNR), frequency-weighted segmental SNR, Perceptual Evaluation of Speech Quality, and mean opinion test scores of 10 normal-hearing volunteers of the adaptive multiband spectral subtraction (MBSS) algorithm were improved by 1.74 dB, 2.11 dB, 0.49, and 0.68, respectively, compared to the conventional fixed-parameter MBSS algorithm. These results indicate that the proposed environment-adaptive management algorithm can be applied to HS devices to improve sound intelligibility for hearing-impaired individuals in various acoustic environments. PMID:25284135

  7. SPEECH ENHANCEMENT BASED ON SELF ADAPTIVE LAGRANGE MULTIPLIER WITH WEIGHTED PERCEPTUAL WIENER DE-NOISING TECHNIQUE

    OpenAIRE

    S. Arjuna Rao*, K. Murali Krishna

    2016-01-01

    The most voice based communication systems facing many problems such as lack of perceptual clarity, musical noise or residual noise, speech distortion and noise distortion. The main objective of speech enhancement is to improve the speech quality and intelligibility. By using wiener filter with Lagrange multiplier makes tradeoff between the speech distortion and residual noise, when the value of Lagrange multiplier is greater than or equal to zero otherwise causes speech distortion and residu...

  8. A de-noising algorithm based on wavelet threshold-exponential adaptive window width-fitting for ground electrical source airborne transient electromagnetic signal

    Science.gov (United States)

    Ji, Yanju; Li, Dongsheng; Yu, Mingmei; Wang, Yuan; Wu, Qiong; Lin, Jun

    2016-05-01

    The ground electrical source airborne transient electromagnetic system (GREATEM) on an unmanned aircraft enjoys considerable prospecting depth, lateral resolution and detection efficiency, etc. In recent years it has become an important technical means of rapid resources exploration. However, GREATEM data are extremely vulnerable to stationary white noise and non-stationary electromagnetic noise (sferics noise, aircraft engine noise and other human electromagnetic noises). These noises will cause degradation of the imaging quality for data interpretation. Based on the characteristics of the GREATEM data and major noises, we propose a de-noising algorithm utilizing wavelet threshold method and exponential adaptive window width-fitting. Firstly, the white noise is filtered in the measured data using the wavelet threshold method. Then, the data are segmented using data window whose step length is even logarithmic intervals. The data polluted by electromagnetic noise are identified within each window based on the discriminating principle of energy detection, and the attenuation characteristics of the data slope are extracted. Eventually, an exponential fitting algorithm is adopted to fit the attenuation curve of each window, and the data polluted by non-stationary electromagnetic noise are replaced with their fitting results. Thus the non-stationary electromagnetic noise can be effectively removed. The proposed algorithm is verified by the synthetic and real GREATEM signals. The results show that in GREATEM signal, stationary white noise and non-stationary electromagnetic noise can be effectively filtered using the wavelet threshold-exponential adaptive window width-fitting algorithm, which enhances the imaging quality.

  9. Experimental ablation of the pancreas with high intensity focused ultrasound (HIFU in a porcine model

    Directory of Open Access Journals (Sweden)

    Biao Xie, Yu-Yuan Li, Lin Jia, Yu-Qiang Nie, Hong Du, Shu-Man Jiang

    2011-01-01

    Full Text Available The aim of this study was to determine the feasibility and safety of high intensity focused ultrasound's (HIFU in pancreatic diseases. Twelve pigs were divided into three groups. The pancreases of pigs in Group A were ablated directly with HIFU, but those in Group B and C ablated by extracorporeal HIFU. The pigs in Group C were sacrificed at day 7 after HIFU. Serological parameters were determined pre-operation and post-operation. The entire pancreas was removed for histological examination. Each animal tolerate the HIFU ablation well. The complete necrosis was observed in targeted regions. The margins of the necrotic regions were clearly delineated from the surrounding normal tissues. Infiltration of inflammatory cells and phorocytosis on the boundary were found in group C. Blood and urine amylase levels were relatively steady after HIFU. No acute pancreatitis or severe complications occurred. In conclusion, HIFU ablation on the pancreas was safe and effective in experimental pigs.

  10. HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

    Science.gov (United States)

    Casper, Andrew Jacob

    The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

  11. Adapting active noise control headsets for the mining industry: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vipac Engineers and Scientists Ltd., North Ryde, NSW (Australia)

    1996-02-01

    Noise induced hearing loss and its consequences with regard to occupational health and safety remain a major problem in the coal industry, especially underground. Australian Standards for exposure to noise in the occupational environment are being lowered from 8-hour equivalent continuous A-weighted sound pressure level of 90 dBA to 85 dBA. The most desirable solution is to treat the noise problem at source. Where noise control strategies are not feasible, the use of hearing protection devices remains the most widely used strategy for limiting the exposure to noise in the work place. This project aimed to demonstrate design specifications for ANC (Active Noise Control) Headsets for use in the coal mining industry, especially underground. Tests showed some devices benefit from a significantly improved noise attenuation performance at low frequencies due the ANC system. Using measured noise from continuous miner and the measured noise attenuation performance of one of the ANC headsets under evaluation as an example, it was demonstrated that with Active Noise Control, the overall Leq noise level was reduced from 90 dBA (with passive hearing protection only) to 77 dBA. The final part of the project was to establish a set of specifications for the manufacturers to use in developing ANC headsets for use underground. (author). 8 tabs., 7 figs., 20 refs.

  12. Experimentelle Untersuchungen zur nichtinvasiven Gewebeablation durch hochenergetischen fokussierten Ultraschall (HIFU)

    OpenAIRE

    Peters, Kristina

    2007-01-01

    Es wurden am neu bewerteten porcinen Nierenmodell mittels hochintensivem fokussierten Ultraschall mit verschiedenen HIFU Behandlungsgeräten Gewebeareale abladiert und die Effekte mittels histologischen Verfahren, Magnetresonanztherapie, Angiographie und einem Ultraschallphantom evaluiert. Es konnte gezeigt werden, dass es bei geeigneter Einstellung möglich ist klinisch relevante Gewebsvolumina zuverlässig, irreversibel zu zerstören.

  13. Spatiotemporal filtering of MR-temperature artifacts arising from bowel motion during transurethral MR-HIFU

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Alain, E-mail: aschmitt@sri.utoronto.ca [Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada); Mougenot, Charles [Philips Healthcare, 281 Hillmount Road, Markham, Ontario L6C 2S3 (Canada); Chopra, Rajiv [Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canadaand Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9061 (United States)

    2014-11-01

    Purpose: Transurethral MR-HIFU is a minimally invasive image-guided treatment for localized prostate cancer that enables precise targeting of tissue within the gland. The treatment is performed within a clinical MRI to obtain real-time MR thermometry used as an active feedback to control the spatial heating pattern in the prostate and to monitor for potential damage to surrounding tissues. This requires that the MR thermometry measurements are an accurate representation of the true tissue temperature. The proton resonance frequency shift thermometry method used is sensitive to tissue motion and changes in the local magnetic susceptibility that can be caused by the motion of air bubbles in the rectum, which can impact the performance of transurethral MR-HIFU in these regions of the gland. Methods: A method is proposed for filtering of temperature artifacts based on the temporal variance of the temperature, using empirical and dynamic positional knowledge of the ultrasonic heating beam, and an estimation of the measurement noise. A two-step correction strategy is introduced which eliminates artifact-detected temperature variations while keeping the noise level low through spatial averaging. Results: The filter has been evaluated by postprocessing data from five human transurethral ultrasound treatments. The two-step correction process led to reduced final temperature standard deviation in the prostate and rectum areas where the artifact was located, without negatively affecting areas distal to the artifact. The performance of the filter was also found to be consistent across all six of the data sets evaluated. The evaluation of the detection criterion parameter M determined that a value of M = 3 achieves a conservative filter with minimal loss of spatial resolution during the process. Conclusions: The filter was able to remove most artifacts due to the presence of moving air bubbles in the rectum during transurethral MR-HIFU. A quantitative estimation of the filter

  14. Rician noise reduction in magnetic resonance images using adaptive non-local mean and guided image filtering

    Science.gov (United States)

    Mahmood, Muhammad Tariq; Chu, Yeon-Ho; Choi, Young-Kyu

    2016-06-01

    This paper proposes a Rician noise reduction method for magnetic resonance (MR) images. The proposed method is based on adaptive non-local mean and guided image filtering techniques. In the first phase, a guidance image is obtained from the noisy image through an adaptive non-local mean filter. Sobel operators are applied to compute the strength of edges which is further used to control the spread of the kernel in non-local mean filtering. In the second phase, the noisy and the guidance images are provided to the guided image filter as input to restore the noise-free image. The improved performance of the proposed method is investigated using the simulated and real data sets of MR images. Its performance is also compared with the previously proposed state-of-the art methods. Comparative analysis demonstrates the superiority of the proposed scheme over the existing approaches.

  15. A multichannel nonlinear adaptive noise canceller based on generalized FLANN for fetal ECG extraction

    Science.gov (United States)

    Ma, Yaping; Xiao, Yegui; Wei, Guo; Sun, Jinwei

    2016-01-01

    In this paper, a multichannel nonlinear adaptive noise canceller (ANC) based on the generalized functional link artificial neural network (FLANN, GFLANN) is proposed for fetal electrocardiogram (FECG) extraction. A FIR filter and a GFLANN are equipped in parallel in each reference channel to respectively approximate the linearity and nonlinearity between the maternal ECG (MECG) and the composite abdominal ECG (AECG). A fast scheme is also introduced to reduce the computational cost of the FLANN and the GFLANN. Two (2) sets of ECG time sequences, one synthetic and one real, are utilized to demonstrate the improved effectiveness of the proposed nonlinear ANC. The real dataset is derived from the Physionet non-invasive FECG database (PNIFECGDB) including 55 multichannel recordings taken from a pregnant woman. It contains two subdatasets that consist of 14 and 8 recordings, respectively, with each recording being 90 s long. Simulation results based on these two datasets reveal, on the whole, that the proposed ANC does enjoy higher capability to deal with nonlinearity between MECG and AECG as compared with previous ANCs in terms of fetal QRS (FQRS)-related statistics and morphology of the extracted FECG waveforms. In particular, for the second real subdataset, the F1-measure results produced by the PCA-based template subtraction (TSpca) technique and six (6) single-reference channel ANCs using LMS- and RLS-based FIR filters, Volterra filter, FLANN, GFLANN, and adaptive echo state neural network (ESN a ) are 92.47%, 93.70%, 94.07%, 94.22%, 94.90%, 94.90%, and 95.46%, respectively. The same F1-measure statistical results from five (5) multi-reference channel ANCs (LMS- and RLS-based FIR filters, Volterra filter, FLANN, and GFLANN) for the second real subdataset turn out to be 94.08%, 94.29%, 94.68%, 94.91%, and 94.96%, respectively. These results indicate that the ESN a and GFLANN perform best, with the ESN a being slightly better than the GFLANN but about four times more

  16. Real-time Monitoring of High Intensity Focused Ultrasound (HIFU) Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound (HMIFU).

    Science.gov (United States)

    Grondin, Julien; Payen, Thomas; Wang, Shutao; Konofagou, Elisa E

    2015-01-01

    Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a technique that can perform and monitor high-intensity focused ultrasound (HIFU) ablation. An oscillatory motion is generated at the focus of a 93-element and 4.5 MHz center frequency HIFU transducer by applying a 25 Hz amplitude-modulated signal using a function generator. A 64-element and 2.5 MHz imaging transducer with 68kPa peak pressure is confocally placed at the center of the HIFU transducer to acquire the radio-frequency (RF) channel data. In this protocol, real-time monitoring of thermal ablation using HIFU with an acoustic power of 7 W on canine livers in vitro is described. HIFU treatment is applied on the tissue during 2 min and the ablated region is imaged in real-time using diverging or plane wave imaging up to 1,000 frames/second. The matrix of RF channel data is multiplied by a sparse matrix for image reconstruction. The reconstructed field of view is of 90° for diverging wave and 20 mm for plane wave imaging and the data are sampled at 80 MHz. The reconstruction is performed on a Graphical Processing Unit (GPU) in order to image in real-time at a 4.5 display frame rate. 1-D normalized cross-correlation of the reconstructed RF data is used to estimate axial displacements in the focal region. The magnitude of the peak-to-peak displacement at the focal depth decreases during the thermal ablation which denotes stiffening of the tissue due to the formation of a lesion. The displacement signal-to-noise ratio (SNRd) at the focal area for plane wave was 1.4 times higher than for diverging wave showing that plane wave imaging appears to produce better displacement maps quality for HMIFU than diverging wave imaging. PMID:26556647

  17. Feasibility of real-time treatment feedback using novel filter for eliminating therapeutic ultrasound noise with high-speed ultrasonic imaging in ultrasound-guided high-intensity focused ultrasound treatment

    Science.gov (United States)

    Takagi, Ryo; Jimbo, Hayato; Iwasaki, Ryosuke; Tomiyasu, Kentaro; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    In the conventional ultrasonic monitoring of high-intensity focused ultrasound (HIFU) treatment, a significant interval between HIFU shots is required when monitoring target tissue to avoid interference between HIFU noise and RF echo signals. In our previous study, a new filtering method to eliminate only HIFU noise while maintaining tissue signals intact was proposed, and it was shown that the thermal coagulation could be detected during simultaneous HIFU irradiation through off-line processing. In this study, the filtering method and a real-time coagulation detection algorithm were implemented in an ultrasound imaging system, whose use for sequential exposure with multiple foci was demonstrated similarly to a commercial HIFU ablation system. The coagulation was automatically detected by the proposed method during real-time simultaneous HIFU irradiation, and the HIFU exposure time was controlled according to the changes in the tissue. The results imply that ultrasonic monitoring with the filtering and detection methods is useful for true real-time detection of changes in the tissue due to thermal coagulation during HIFU exposure.

  18. EEG/ERP adaptive noise canceller design with controlled search space (CSS) approach in cuckoo and other optimization algorithms.

    Science.gov (United States)

    Ahirwal, M K; Kumar, Anil; Singh, G K

    2013-01-01

    This paper explores the migration of adaptive filtering with swarm intelligence/evolutionary techniques employed in the field of electroencephalogram/event-related potential noise cancellation or extraction. A new approach is proposed in the form of controlled search space to stabilize the randomness of swarm intelligence techniques especially for the EEG signal. Swarm-based algorithms such as Particles Swarm Optimization, Artificial Bee Colony, and Cuckoo Optimization Algorithm with their variants are implemented to design optimized adaptive noise canceler. The proposed controlled search space technique is tested on each of the swarm intelligence techniques and is found to be more accurate and powerful. Adaptive noise canceler with traditional algorithms such as least-mean-square, normalized least-mean-square, and recursive least-mean-square algorithms are also implemented to compare the results. ERP signals such as simulated visual evoked potential, real visual evoked potential, and real sensorimotor evoked potential are used, due to their physiological importance in various EEG studies. Average computational time and shape measures of evolutionary techniques are observed 8.21E-01 sec and 1.73E-01, respectively. Though, traditional algorithms take negligible time consumption, but are unable to offer good shape preservation of ERP, noticed as average computational time and shape measure difference, 1.41E-02 sec and 2.60E+00, respectively. PMID:24407307

  19. HIFU and Chemotherapy Synergistic Inhibitory Effect on Dunning AT2 Tumour-Bearing Rats

    Science.gov (United States)

    Curiel, Laura; Paparel, Philipe; Chesnais, Sabrina; Gelet, Albert; Chapelon, Jean-Yves

    2005-03-01

    Since there is no 100% satisfactory treatment for localized prostate cancer in patients presenting symptoms representing a poor prognosis (stage T3, high Gleason score, PSA level greater than 15 ng/ml, etc.), this study aimed to evaluate the therapeutic and synergistic inhibition effects of using High Intensity Focused Ultrasound (HIFU) in combination with chemotherapy (Taxane + Estramustine). Forty-one Dunning AT2 tumour-bearing Copenhagen rats receiving HIFU and/or chemotherapy were divided into four groups: control group; chemotherapy group; HIFU group; and HIFU-chemotherapy combined group. Increase in the tumour volume was observed over 3 weeks and the tumour volume doubling time was evaluated. Growth curves for each group were then plotted and statistically evaluated. HIFU treatment combined with Taxane + Estramusine was found to have a significant synergistic effect; on day 30, the distribution of tumour volume relative to the treatment group was significantly different (p = 0.0007). The control group volumes were significantly greater than those of the chemotherapy-only (p = 0.006) or HIFU-only group (p = 0.006). The greatest difference was observed between the chemotherapy plus HIFU combined group and the control group. Additionally, tumour-doubling times were 7.7 days for the control group, 13.2 days for the HIFU-only group, and 31.2 days for the chemotherapy plus HIFU group. The differences in tumour growth rates between the chemotherapy plus HIFU combined group and a chemotherapy-only + HIFU-only grouping was 3.8% (p = 0.0020). Thus, the combined chemotherapy plus HIFU treatment was clearly more effective in reducing the tumour size than HIFU only or chemotherapy only, which indicates a synergy between the two types of treatment. Our results suggest that this combined therapy could be useful for the treatment of high-risk prostate cancer.

  20. Adaptive Noise Model for Transform Domain Wyner-Ziv Video using Clustering of DCT Blocks

    DEFF Research Database (Denmark)

    Luong, Huynh Van; Huang, Xin; Forchhammer, Søren

    2011-01-01

    The noise model is one of the most important aspects influencing the coding performance of Distributed Video Coding. This paper proposes a novel noise model for Transform Domain Wyner-Ziv (TDWZ) video coding by using clustering of DCT blocks. The clustering algorithm takes advantage of the residual...

  1. Implementation of Adaptive Filter Structures on a Fixed Point Signal Processor for Acoustical Noise Reduction

    OpenAIRE

    Chunduri, Krishna Chaitanya; Gutti, Chalapathi

    2005-01-01

    The problem of controlling the noise level in the environment has been the focus of a tremendous amount of research over the years. Active Noise Cancellation (ANC) is one such approach that has been proposed for reduction of steady state noise. ANC refers to an electromechanical or electro acoustic technique of canceling an acoustic disturbance to yield a quieter environment. The basic principle of ANC is to introduce a canceling “anti-noise” signal that has the same amplitude but the exact o...

  2. Speech Enhancement Algorithm Using Sub band Two Step Decision Directed Approach with Adaptive Weighting factor and Noise Masking Threshold

    Directory of Open Access Journals (Sweden)

    Deepa Dhanaskodi

    2011-01-01

    Full Text Available Problem statement: Speech Enhancement plays an important role in any of the speech processing systems like speech recognition, mobile communication, hearing aid. Approach: In this work, human perceptual auditory masking effect is incorporated into the single channel speech enhancement algorithm. The algorithm is based on a criterion by which the audible noise may be masked rather than being attenuated and thereby reducing the chance of distortion to speech. The basic decision directed approach is for efficient reduction of musical noise, that includes the estimation of the a priori SNR which is a crucial parameter of the spectral gain, follows the a posteriori SNR with a delay of one frame in speech frames. In this work a simple adaptive speech enhancement technique, using an adaptive sigmoid type function to determine the weighting factor of the TSDD algorithm is employed based on a sub band approach. In turn the spectral estimate is used to obtain a perceptual gain factor. Results: Objective and subjective measures like SNR, MSE, IS distance and were obtained, which shows the ability of the proposed method for efficient enhancement of noisy speech Conclusion/Recommendations: Performance assessment shows that our proposal can achieve a more significant noise reduction and a better spectral estimation of weak speech spectral components from a noisy signal as compared to the conventional speech enhancement algorithm.

  3. High-Intensity Focused Ultrasound (HIFU) in Uterine Fibroid Treatment: Review Study

    OpenAIRE

    MAHMOUD, MUSTAFA Z.; Alkhorayef, Mohammed; Alzimami, Khalid S.; Aljuhani, Manal Saud; Sulieman, Abdelmoneim

    2014-01-01

    Summary Background High-intensity focused ultrasound (HIFU) is a highly precise medical procedure used locally to heat and destroy diseased tissue through ablation. This study intended to review HIFU in uterine fibroid therapy, to evaluate the role of HIFU in the therapy of leiomyomas as well as to review the actual clinical activities in this field including efficacy and safety measures beside the published clinical literature. Material/Methods An inclusive literature review was carried out ...

  4. High intensity focused ultrasound (HIFU) as the alternative method of treatment of oncourological diseases

    OpenAIRE

    Blyumberg B.I.; Fomkin R.N.; Popkov V.M.

    2012-01-01

    Increasing interest devoted to technology of high intensity focused ultrasound (high-intensity focused ultrasound, HIFU), basically, is explained by a wide spectrum of potential fields of application at minimum invasiveness of the given method. In oncourology HIFU is applied in prostate and kidney cancer. In case of tumors of renal parenchyma the given technique is being clinically tested, while HIFU is currently used in the practice of European oncourologists in treatment of prostate cancer....

  5. Immune System Modulation with LOFU And HIFU Treatment of Prostate Cancer

    Science.gov (United States)

    Guha, C.; Huagang, Z.; Chen, W.; Carlosn, R.; Sanghvi, N. T.

    2011-09-01

    High intensity focused ultrasound (HIFU) results in instantaneous coagulative tissue necrosis. In contrast, "low" energy focused ultrasound (LOFU) induces membrane perturbation while maintaining cell viability. This report explores the tumor immunomodulatory roles of LOFU and HIFU combination treatment. We hypothesized that administration of repeated cycles of LOFU, followed by HIFU would release tumor-derived peptide-heat shock protein complexes in the blood and induce systemic tumor-specific immune response that would enhance tumor control of both local and systemic disease.

  6. An adaptive integrated algorithm for noninvasive fetal ECG separation and noise reduction based on ICA-EEMD-WS.

    Science.gov (United States)

    Liu, Guangchen; Luan, Yihui

    2015-11-01

    High-resolution fetal electrocardiogram (FECG) plays an important role in assisting physicians to detect fetal changes in the womb and to make clinical decisions. However, in real situations, clear FECG is difficult to extract because it is usually overwhelmed by the dominant maternal ECG and other contaminated noise such as baseline wander, high-frequency noise. In this paper, we proposed a novel integrated adaptive algorithm based on independent component analysis (ICA), ensemble empirical mode decomposition (EEMD), and wavelet shrinkage (WS) denoising, denoted as ICA-EEMD-WS, for FECG separation and noise reduction. First, ICA algorithm was used to separate the mixed abdominal ECG signal and to obtain the noisy FECG. Second, the noise in FECG was reduced by a three-step integrated algorithm comprised of EEMD, useful subcomponents statistical inference and WS processing, and partial reconstruction for baseline wander reduction. Finally, we evaluate the proposed algorithm using simulated data sets. The results indicated that the proposed ICA-EEMD-WS outperformed the conventional algorithms in signal denoising. PMID:26429348

  7. High-Intensity Focused Ultrasound (HIFU) in Uterine Fibroid Treatment: Review Study

    International Nuclear Information System (INIS)

    High-intensity focused ultrasound (HIFU) is a highly precise medical procedure used locally to heat and destroy diseased tissue through ablation. This study intended to review HIFU in uterine fibroid therapy, to evaluate the role of HIFU in the therapy of leiomyomas as well as to review the actual clinical activities in this field including efficacy and safety measures beside the published clinical literature. An inclusive literature review was carried out in order to review the scientific foundation, and how it resulted in the development of extracorporeal distinct devices. Studies addressing HIFU in leiomyomas were identified from a search of the Internet scientific databases. The analysis of literature was limited to journal articles written in English and published between 2000 and 2013. In current gynecologic oncology, HIFU is used clinically in the treatment of leiomyomas. Clinical research on HIFU therapy for leiomyomas began in the 1990s, and the majority of patients with leiomyomas were treated predominantly with HIFUNIT 9000 and prototype single focus ultrasound devices. HIFU is a non-invasive and highly effective standard treatment with a large indication range for all sizes of leiomyomas, associated with high efficacy, low operative morbidity and no systemic side effects. Uterine fibroid treatment using HIFU was effective and safe in treating symptomatic uterine fibroids. Few studies are available in the literature regarding uterine artery embolization (UAE). HIFU provides an excellent option to treat uterine fibroids

  8. The role of numerical simulation for the development of an advanced HIFU system

    Science.gov (United States)

    Okita, Kohei; Narumi, Ryuta; Azuma, Takashi; Takagi, Shu; Matumoto, Yoichiro

    2014-10-01

    High-intensity focused ultrasound (HIFU) has been used clinically and is under clinical trials to treat various diseases. An advanced HIFU system employs ultrasound techniques for guidance during HIFU treatment instead of magnetic resonance imaging in current HIFU systems. A HIFU beam imaging for monitoring the HIFU beam and a localized motion imaging for treatment validation of tissue are introduced briefly as the real-time ultrasound monitoring techniques. Numerical simulations have a great impact on the development of real-time ultrasound monitoring as well as the improvement of the safety and efficacy of treatment in advanced HIFU systems. A HIFU simulator was developed to reproduce ultrasound propagation through the body in consideration of the elasticity of tissue, and was validated by comparison with in vitro experiments in which the ultrasound emitted from the phased-array transducer propagates through the acrylic plate acting as a bone phantom. As the result, the defocus and distortion of the ultrasound propagating through the acrylic plate in the simulation quantitatively agree with that in the experimental results. Therefore, the HIFU simulator accurately reproduces the ultrasound propagation through the medium whose shape and physical properties are well known. In addition, it is experimentally confirmed that simulation-assisted focus control of the phased-array transducer enables efficient assignment of the focus to the target. Simulation-assisted focus control can contribute to design of transducers and treatment planning.

  9. Combination of the transurethral resection and prostate HIFU ablation at treatment of the localized cancer

    Directory of Open Access Journals (Sweden)

    Popkov V.M.

    2014-09-01

    26 patients were included into HIFU and 74 group in group of the combined treatment (TURP+HIFU. Selection criteria for HIFU ablation were the localized cancer of a prostate concerning which earlier it wasn't carried out treatments, and level of a PSA at the time of statement of the diagnosis 15 ng/ml. All patients corresponding to these by criteria, were considered as candidates for treatment and inclusion in the analysis. The nadir and stability of PSA, the histologic conclusion, IPSS, quality of life and complication were estimated at time of postoperative supervision. Results: Statistically significant influence of a combination TURP+HIFU for the term of transurethral drainage of a bladder (a median of 40 days against 7 days, incontience frequency (15.4% against 6.9%, infections of urinary ways (47.9% against 11.4% and IPSS change during the postoperative period (on the average 8.91 against 3.37 is noted. During the short period of supervision it wasn't observed considerable changes in relation to efficiency: in HIFU group the frequency of repeated sessions made 25%, in TUR/HIFU group 4%. Conclusion: HIFU therapy is modern, minimum invasive method of a cancer therapy of a prostate. The combination of a transurethral resection and HIFU ablation significantly reduces the frequency of the complications connected with treatment. Maintaining the patient after combined TURP and HIFU ablation is comparable with maintaining the patient after usual TURP.

  10. HIFU Hemostasis of Liver Injuries Enhanced by Ultrasound Contrast Agents

    Science.gov (United States)

    Zderic, Vesna; Vaezy, Shahram; Brayman, Andrew A.; Matula, Thomas J.; O'Keefe, Grant E.; Crum, Lawrence A.

    2005-03-01

    Our objective was to investigate whether High-Intensity Focused Ultrasound (HIFU) hemostasis can be achieved faster in the presence of ultrasound contrast agents (UCA). Incisions (3 cm long and 0.5 cm deep) were made in surgically exposed rabbit liver. Optison at a concentration of 0.18 ml/kg was injected into the mesenteric vein, immediately before the incision was made. The HIFU applicator (frequency of 5.5 MHz, and intensity of 3,700 W/cm2) was scanned manually over the incision (at an approximate rate of 1 mm/s) until hemostasis was achieved. The times to complete hemostasis were measured and normalized with the initial blood loss. The hemostasis times were 59±23 s in the presence of Optison and 70±23 s without Optison. The presence of Optison produced a 37% reduction in the normalized hemostasis times (phemostasis of internal organ injuries.

  11. Wireless rake-receiver using adaptive filter with a family of partial update algorithms in noise cancellation applications

    Science.gov (United States)

    Fayadh, Rashid A.; Malek, F.; Fadhil, Hilal A.; Aldhaibani, Jaafar A.; Salman, M. K.; Abdullah, Farah Salwani

    2015-05-01

    For high data rate propagation in wireless ultra-wideband (UWB) communication systems, the inter-symbol interference (ISI), multiple-access interference (MAI), and multiple-users interference (MUI) are influencing the performance of the wireless systems. In this paper, the rake-receiver was presented with the spread signal by direct sequence spread spectrum (DS-SS) technique. The adaptive rake-receiver structure was shown with adjusting the receiver tap weights using least mean squares (LMS), normalized least mean squares (NLMS), and affine projection algorithms (APA) to support the weak signals by noise cancellation and mitigate the interferences. To minimize the data convergence speed and to reduce the computational complexity by the previous algorithms, a well-known approach of partial-updates (PU) adaptive filters were employed with algorithms, such as sequential-partial, periodic-partial, M-max-partial, and selective-partial updates (SPU) in the proposed system. The simulation results of bit error rate (BER) versus signal-to-noise ratio (SNR) are illustrated to show the performance of partial-update algorithms that have nearly comparable performance with the full update adaptive filters. Furthermore, the SPU-partial has closed performance to the full-NLMS and full-APA while the M-max-partial has closed performance to the full-LMS updates algorithms.

  12. Design of Adaptive Filter Using Jordan/Elman Neural Network in a Typical EMG Signal Noise Removal

    Directory of Open Access Journals (Sweden)

    V. R. Mankar

    2009-01-01

    Full Text Available The bioelectric potentials associated with muscle activity constitute the electromyogram (EMG. These EMG signals are low-frequency and lower-magnitude signals. In this paper, it is presented that Jordan/Elman neural network can be effectively used for EMG signal noise removal, which is a typical nonlinear multivariable regression problem, as compared with other types of neural networks. Different neural network (NN models with varying parameters were considered for the design of adaptive neural-network-based filter which is a typical SISO system. The performance parameters, that is, MSE, correlation coefficient, N/P, and t, are found to be in the expected range of values.

  13. CT and Ultrasound Guided Stereotactic High Intensity Focused Ultrasound (HIFU)

    International Nuclear Information System (INIS)

    To demonstrate the feasibility of CT and B-mode Ultrasound (US) targeted HIFU, a prototype coaxial focused ultrasound transducer was registered and integrated to a CT scanner. CT and diagnostic ultrasound were used for HIFU targeting and monitoring, with the goals of both thermal ablation and non-thermal enhanced drug delivery. A 1 megahertz coaxial ultrasound transducer was custom fabricated and attached to a passive position-sensing arm and an active six degree-of-freedom robotic arm via a CT stereotactic frame. The outer therapeutic transducer with a 10 cm fixed focal zone was coaxially mounted to an inner diagnostic US transducer (2-4 megahertz, Philips Medical Systems). This coaxial US transducer was connected to a modified commercial focused ultrasound generator (Focus Surgery, Indianapolis, IN) with a maximum total acoustic power of 100 watts. This pre-clinical paradigm was tested for ability to heat tissue in phantoms with monitoring and navigation from CT and live US. The feasibility of navigation via image fusion of CT with other modalities such as PET and MRI was demonstrated. Heated water phantoms were tested for correlation between CT numbers and temperature (for ablation monitoring). The prototype transducer and integrated CT/US imaging system enabled simultaneous multimodality imaging and therapy. Pre-clinical phantom models validated the treatment paradigm and demonstrated integrated multimodality guidance and treatment monitoring. Temperature changes during phantom cooling corresponded to CT number changes. Contrast enhanced or non-enhanced CT numbers may potentially be used to monitor thermal ablation with HIFU. Integrated CT, diagnostic US, and therapeutic focused ultrasound bridges a gap between diagnosis and therapy. Preliminary results show that the multimodality system may represent a relatively inexpensive, accessible, and simple method of both targeting and monitoring HIFU effects. Small animal pre-clinical models may be translated to large

  14. Analytical and experimental results for active noise control within cylindrical cavities bounded by elastic adaptive structures

    Energy Technology Data Exchange (ETDEWEB)

    Baier, H.; Dool, T. van den; Haeusler, S.; Faust, M. [Technische Univ. Muenchen (Germany)]|[TNO, Delf (Netherlands)]|[Dornier, Friedrichshafen (Germany)

    1998-10-01

    The feasibility of differnt concepts for active noise control in elastically bounded cylindrical cavities such as in launcher fairings is investigated. Analytical and experimental studies are carried out for feedforward and feedback controllers and different types of actuators and sensors. The feasibility and potential of the approach is demonstrated, but further progress on controller speed and actuator capability has to be made. (orig.)

  15. OCAM2S: an integral shutter ultrafast and low noise wavefront sensor camera for laser guide stars adaptive optics systems

    Science.gov (United States)

    Gach, Jean-Luc; Feautrier, Philippe; Balard, Philippe; Guillaume, Christian; Stadler, Eric

    2014-07-01

    To date, the OCAM2 system has demonstrated to be the fastest and lowest noise production ready wavefront sensor, achieving 2067 full frames per second with subelectron readout noise. This makes OCAM2 the ideal system for natural as well as continuous wave laser guide star wavefront sensing. In this paper we present the new gated version of OCAM2 named OCAM2-S, using E2V's CCD219 sensor with integral shutter. This new camera offers the same superb characteristics than OCAM2 both in terms of speed and readout noise but also offers a shutter function that makes the sensor only sensitive to light for very short periods, at will. We will report on gating time and extinction ratio performances of this new camera. This device opens new possibilities for Rayleigh pulsed lasers adaptive optics systems. With a shutter time constant well below 1 microsecond, this camera opens new solutions for pulsed sodium lasers with backscatter suppression or even spot elongation minimization for ELT LGS.

  16. Integrated WiFi/PDR/Smartphone Using an Adaptive System Noise Extended Kalman Filter Algorithm for Indoor Localization

    Directory of Open Access Journals (Sweden)

    Xin Li

    2016-02-01

    Full Text Available Wireless signal strength is susceptible to the phenomena of interference, jumping, and instability, which often appear in the positioning results based on Wi-Fi field strength fingerprint database technology for indoor positioning. Therefore, a Wi-Fi and PDR (pedestrian dead reckoning real-time fusion scheme is proposed in this paper to perform fusing calculation by adaptively determining the dynamic noise of a filtering system according to pedestrian movement (straight or turning, which can effectively restrain the jumping or accumulation phenomena of wireless positioning and the PDR error accumulation problem. Wi-Fi fingerprint matching typically requires a quite high computational burden: To reduce the computational complexity of this step, the affinity propagation clustering algorithm is adopted to cluster the fingerprint database and integrate the information of the position domain and signal domain of respective points. An experiment performed in a fourth-floor corridor at the School of Environment and Spatial Informatics, China University of Mining and Technology, shows that the traverse points of the clustered positioning system decrease by 65%–80%, which greatly improves the time efficiency. In terms of positioning accuracy, the average error is 4.09 m through the Wi-Fi positioning method. However, the positioning error can be reduced to 2.32 m after integration of the PDR algorithm with the adaptive noise extended Kalman filter (EKF.

  17. Wavelet domain adaptive filtering algorithm for removing the seamless pipe noise contained in the magnetic flux leakage data

    Institute of Scientific and Technical Information of China (English)

    Han Wenhua; Que Peiwen

    2006-01-01

    With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage (MFL) method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise (SPN). SPN can in some cases completely mask MFL signals from certain type of defects,and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.

  18. Adaptive Filtering for FSCW Signal-to-noise Ratio Enhancement of SAW Interrogation Units

    Directory of Open Access Journals (Sweden)

    Díaz Luis

    2016-01-01

    Full Text Available A digital filter that improves the signal-to-noise ratio of the response of a FSCW (Frequency Stepped Continuous Wave scheme is presented. An improvement in signal-to-noise ratio represents an enhanced readout distance. This work considers this architecture as an interrogation unit for SAW tags with time and phase encoding. The parameters of the proposed digital filter, which is a non-linear edge preserving filter, were studied and tested for this specific application. An improvement of around 20dB in the SNR level was achieved. This filter preserves the phase of the signal at the time position of the reflectors, which is critical for correct identification of the code in phase encoding schemes.

  19. Multi-microphone adaptive noise reduction strategies for coordinated stimulation in bilateral cochlear implant devices

    OpenAIRE

    Kokkinakis, Kostas; Loizou, Philipos C.

    2010-01-01

    Bilateral cochlear implant (BI-CI) recipients achieve high word recognition scores in quiet listening conditions. Still, there is a substantial drop in speech recognition performance when there is reverberation and more than one interferers. BI-CI users utilize information from just two directional microphones placed on opposite sides of the head in a so-called independent stimulation mode. To enhance the ability of BI-CI users to communicate in noise, the use of two computationally inexpensi...

  20. Improved Reproduction of Stops in Noise Reduction Systems with Adaptive Windows and Nonstationarity Detection

    Directory of Open Access Journals (Sweden)

    Dirk Mauler

    2009-01-01

    Full Text Available A new block-based noise reduction system is proposed which focuses on the preservation of transient sounds like stops or speech onsets. The power level of consonants has been shown to be important for speech intelligibility. In single-channel noise reduction systems, however, these sounds are frequently severely attenuated. The main reasons for this are an insufficient temporal resolution of transient sounds and a delayed tracking of important control parameters. The key idea of the proposed system is the detection of non-stationary input data. Depending on that decision, a pair of spectral analysis-synthesis windows is selected which either provides high temporal or high spectral resolution. Furthermore, the decision-directed approach for the estimation of the a priori SNR is modified so that speech onsets are tracked more quickly without sacrificing performance in stationary signal regions. The proposed solution shows significant improvements in the preservation of stops with an overall system delay (input-output, excluding group delay of noise reduction filter of only 10 milliseconds.

  1. Stochastic optimal control and estimation methods adapted to the noise characteristics of the sensorimotor system.

    Science.gov (United States)

    Todorov, Emanuel

    2005-05-01

    Optimality principles of biological movement are conceptually appealing and straightforward to formulate. Testing them empirically, however, requires the solution to stochastic optimal control and estimation problems for reasonably realistic models of the motor task and the sensorimotor periphery. Recent studies have highlighted the importance of incorporating biologically plausible noise into such models. Here we extend the linear-quadratic-gaussian framework--currently the only framework where such problems can be solved efficiently--to include control-dependent, state-dependent, and internal noise. Under this extended noise model, we derive a coordinate-descent algorithm guaranteed to converge to a feedback control law and a nonadaptive linear estimator optimal with respect to each other. Numerical simulations indicate that convergence is exponential, local minima do not exist, and the restriction to nonadaptive linear estimators has negligible effects in the control problems of interest. The application of the algorithm is illustrated in the context of reaching movements. A Matlab implementation is available at www.cogsci.ucsd.edu/~todorov.

  2. High intensity focused ultrasound (HIFU as the alternative method of treatment of oncourological diseases

    Directory of Open Access Journals (Sweden)

    Blyumberg B.I.

    2012-12-01

    Full Text Available Increasing interest devoted to technology of high intensity focused ultrasound (high-intensity focused ultrasound, HIFU, basically, is explained by a wide spectrum of potential fields of application at minimum invasiveness of the given method. In oncourology HIFU is applied in prostate and kidney cancer. In case of tumors of renal parenchyma the given technique is being clinically tested, while HIFU is currently used in the practice of European oncourologists in treatment of prostate cancer. The majority of the references describing the results of HIFU application in prostate cancer is based on data of a number of clinical observations. It has been proved that HIFU is a possible method of treatment of highly — and moderate-differentiated tumors, and local relapses after remote radial therapy.

  3. Adaptive Echo Noise Elimination for Speech Enhancement of Tamil letter ‘Zha’

    Directory of Open Access Journals (Sweden)

    A. Srinivasan

    2009-12-01

    Full Text Available Acoustic echo depends on time delay between initial and reflected sound wave, strength of reflected sound. In the speech processing of letter ‘zha’ [11], echo of the recorded voice gives the spurious results. Such complexity can be avoided by suitable pyramidalmethod like adaptive filtering technique. Adaptive filtering tries to adjust these parameters with the aim of meeting some well-defined target, which depends upon the state of the system and surroundings. In speech recognition, the acoustic echo gives the faulty results.Objective of this paper is to analyze the performance of various adaptive filtering algorithms for acoustic echo cancellation in recorded speech enhancement of the letter ‘Zha’ in Tamil language. These algorithms are simulated in MATLAB and compared with theperformance of those algorithms based on parameters such us computational complexity, convergence rate and amount of echo attenuation.

  4. Dual adaptive statistical approach for quantitative noise reduction in photon-counting medical imaging: application to nuclear medicine images

    International Nuclear Information System (INIS)

    Noise reduction in photon-counting images remains challenging, especially at low count levels. We have developed an original procedure which associates two complementary filters using a Wiener-derived approach. This approach combines two statistically adaptive filters into a dual-weighted (DW) filter. The first one, a statistically weighted adaptive (SWA) filter, replaces the central pixel of a sliding window with a statistically weighted sum of its neighbors. The second one, a statistical and heuristic noise extraction (extended) (SHINE-Ext) filter, performs a discrete cosine transformation (DCT) using sliding blocks. Each block is reconstructed using its significant components which are selected using tests derived from multiple linear regression (MLR). The two filters are weighted according to Wiener theory. This approach has been validated using a numerical phantom and a real planar Jaszczak phantom. It has also been illustrated using planar bone scintigraphy and myocardial single-photon emission computed tomography (SPECT) data. Performances of filters have been tested using mean normalized absolute error (MNAE) between the filtered images and the reference noiseless or high-count images.Results show that the proposed filters quantitatively decrease the MNAE in the images and then increase the signal-to-noise Ratio (SNR). This allows one to work with lower count images. The SHINE-Ext filter is well suited to high-size images and low-variance areas. DW filtering is efficient for low-size images and in high-variance areas. The relative proportion of eliminated noise generally decreases when count level increases. In practice, SHINE filtering alone is recommended when pixel spacing is less than one-quarter of the effective resolution of the system and/or the size of the objects of interest. It can also be used when the practical interest of high frequencies is low. In any case, DW filtering will be preferable.The proposed filters have been applied to nuclear

  5. 多通道自适应噪声抵消系统%An adaptive multi-channel anti-noise system

    Institute of Scientific and Technical Information of China (English)

    于新颖

    2015-01-01

    对多通道自适应噪声抵消系统的噪声抑制能力进行了MATLAB仿真分析,结果表明,多通道系统的抑噪能力高于单通道系统,信噪比增益提高了1.36 dB左右。%We study the noise checking ability of an adaptive multi‐channel anti‐noise system with MATLAB simulation .The results show that the noise checking ability of the adaptive multi‐channel system is better than that of single‐channel ,and the signal‐to‐noise ratio increases by about 1 .36 dB .

  6. Adaptive Signal Detection and Parameter Estimation in Unknown Colored Gaussian Noise

    CERN Document Server

    Tang, Bo; Kay, Steven

    2016-01-01

    This paper considers the general signal detection and parameter estimation problem in the presence of colored Gaussian noise disturbance. By modeling the disturbance with an autoregressive process, we present three signal detectors with different unknown parameters under the general framework of binary hypothesis testing. The closed form of parameter estimates and the asymptotic distributions of these three tests are also given. Given two examples of frequency modulated signal detection problem and time series moving object detection problem, the simulation results demonstrate the effectiveness of three presented detectors.

  7. Combination of bubble liposomes and high-intensity focused ultrasound (HIFU) enhanced antitumor effect by tumor ablation.

    Science.gov (United States)

    Hamano, Nobuhito; Negishi, Yoichi; Takatori, Kyohei; Endo-Takahashi, Yoko; Suzuki, Ryo; Maruyama, Kazuo; Niidome, Takuro; Aramaki, Yukihiko

    2014-01-01

    Ultrasound (US) is used in the clinical setting not only for diagnosis but also for therapy. As a therapeutic US technique, high-intensity focused ultrasound (HIFU) can be applied to treat cancer in a clinical setting. Microbubbles increased temperature and improved the low therapeutic efficiency under HIFU; however, microbubbles have room for improvement in size, stability, and targeting ability. To solve these issues, we reported that "Bubble liposomes" (BLs) containing the US imaging gas (perfluoropropane gas) liposomes were suitable for ultrasound imaging and gene delivery. In this study, we examined whether BLs and HIFU could enhance the ablation area of the tumor and the antitumor effect. First, we histologically analyzed the tumor after BLs and HIFU. The ablation area of the treatment of BLs and HIFU was broader than that of HIFU alone. Next, we monitored the temperature of the tumor, and examined the antitumor effect. The temperature increase with BLs and HIFU treatment was faster and higher than that with HIFU alone. Moreover, treatment with BLs and HIFU enhanced the antitumor effect, which was better than with HIFU alone. Thus, the combination of BLs and HIFU could be efficacious for cancer therapy.

  8. Seismic random noise elimination according to the adaptive fractal conservation law

    Science.gov (United States)

    Meng, Fanlei; Li, Yue; Zeng, Qian

    2016-05-01

    The fractal conservation law (FCL) is based on the Cauchy problem of the partial differential equation (PDE), which is modified by an anti-diffusive term of lower order. The analysis indicates that it can eliminate the high frequencies and preserve or amplify the low/medium frequencies. The performance of FCL depends on the threshold selected for the PDE. This threshold corresponds to the cut-off frequency of FCL in the frequency domain. Generally, the threshold is fixed. Thus, the FCL cannot track the signal beyond the cut-off frequency, and it removes the higher-frequency components of the signal. To solve this problem, an adaptive FCL filtering method is presented. The main purpose of this method is to select the optimal FCL threshold in each sample index such that it can adaptively track the rapid changes in the signal. In the adaptive FCL, we select FCL estimations with different thresholds and construct a convex hull of these estimations of each sample index. Consequently, we introduce a quadratic functional with respect to FCL estimation to ensure that we select the optimal estimation from the convex hull of each sample index. This leads to a box-constrained convex problem, which can be solved by the Viterbi algorithm.

  9. 自适应滤波在有源消声中的应用%Application of adaptive filter in active noise control

    Institute of Scientific and Technical Information of China (English)

    于华民; 朱海潮; 施引; 吴正国

    2001-01-01

    从分析有源消声的难点出发,综述了自适应滤波算法在有源消声中的应用,给出了相应的实例.对自适应滤波在有源消声中应用的未来发展趋势作了展望.%With focus on the difficulties of ANC(active noise control), the application of adaptive filter in active noise control is reviewed, and some practical examples are also displayed. Finally, prospect of adaptive filter in ANC is proposed.

  10. Weak-lensing shear estimates with general adaptive moments, and studies of bias by pixellation, PSF distortions, and noise

    CERN Document Server

    Simon, Patrick

    2016-01-01

    In weak gravitational lensing, weighted quadrupole moments of the brightness profile in galaxy images are a common way to estimate gravitational shear. We employ general adaptive moments (GLAM) to study causes of shear bias on a fundamental level and for a practical definition of an image ellipticity. For GLAM, the ellipticity is identical to that of isophotes of elliptical images, and this ellipticity is always an unbiased estimator of reduced shear. Our theoretical framework reiterates that moment-based techniques are similar to a model-based approach in the sense that they fit an elliptical profile to the image to obtain weighted moments. As a result, moment-based estimates of ellipticities are prone to underfitting bias. The estimation is fundamentally limited mainly by pixellation which destroys information on the original, pre-seeing image. We give an optimized estimator for the pre-seeing GLAM ellipticity and its bias for noise-free images. To deal with images where pixel noise is prominent, we conside...

  11. Segmentation of uterine fibroid ultrasound images using a dynamic statistical shape model in HIFU therapy.

    Science.gov (United States)

    Ni, Bo; He, Fazhi; Yuan, ZhiYong

    2015-12-01

    Segmenting the lesion areas from ultrasound (US) images is an important step in the intra-operative planning of high-intensity focused ultrasound (HIFU). However, accurate segmentation remains a challenge due to intensity inhomogeneity, blurry boundaries in HIFU US images and the deformation of uterine fibroids caused by patient's breathing or external force. This paper presents a novel dynamic statistical shape model (SSM)-based segmentation method to accurately and efficiently segment the target region in HIFU US images of uterine fibroids. For accurately learning the prior shape information of lesion boundary fluctuations in the training set, the dynamic properties of stochastic differential equation and Fokker-Planck equation are incorporated into SSM (referred to as SF-SSM). Then, a new observation model of lesion areas (named to RPFM) in HIFU US images is developed to describe the features of the lesion areas and provide a likelihood probability to the prior shape given by SF-SSM. SF-SSM and RPFM are integrated into active contour model to improve the accuracy and robustness of segmentation in HIFU US images. We compare the proposed method with four well-known US segmentation methods to demonstrate its superiority. The experimental results in clinical HIFU US images validate the high accuracy and robustness of our approach, even when the quality of the images is unsatisfactory, indicating its potential for practical application in HIFU therapy.

  12. Segmentation of uterine fibroid ultrasound images using a dynamic statistical shape model in HIFU therapy.

    Science.gov (United States)

    Ni, Bo; He, Fazhi; Yuan, ZhiYong

    2015-12-01

    Segmenting the lesion areas from ultrasound (US) images is an important step in the intra-operative planning of high-intensity focused ultrasound (HIFU). However, accurate segmentation remains a challenge due to intensity inhomogeneity, blurry boundaries in HIFU US images and the deformation of uterine fibroids caused by patient's breathing or external force. This paper presents a novel dynamic statistical shape model (SSM)-based segmentation method to accurately and efficiently segment the target region in HIFU US images of uterine fibroids. For accurately learning the prior shape information of lesion boundary fluctuations in the training set, the dynamic properties of stochastic differential equation and Fokker-Planck equation are incorporated into SSM (referred to as SF-SSM). Then, a new observation model of lesion areas (named to RPFM) in HIFU US images is developed to describe the features of the lesion areas and provide a likelihood probability to the prior shape given by SF-SSM. SF-SSM and RPFM are integrated into active contour model to improve the accuracy and robustness of segmentation in HIFU US images. We compare the proposed method with four well-known US segmentation methods to demonstrate its superiority. The experimental results in clinical HIFU US images validate the high accuracy and robustness of our approach, even when the quality of the images is unsatisfactory, indicating its potential for practical application in HIFU therapy. PMID:26459767

  13. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Science.gov (United States)

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect.

  14. Approaches to overcome current limitations of HIFU treatment

    Science.gov (United States)

    Umemura, Shin-Ichiro; Kawabata, Ken-Ichi; Sasaki, Kazuaki; Azuma, Takashi; Ishida, Kazunari; Kubota, Jun; Ichihara, Mitsuyoshi; Okai, Takashi

    2001-05-01

    Noninvasive therapy with HIFU has been successfully applied to transrectal treatment of prostate cancer as well as benign prostate hyperplasia. However, there are two major technical reasons why its clinical application to other organs is currently limited: (1) low throughput of treatment and (2) lack of penetration to deep tissues. To multiply the throughput, a split-focus technique, in which the focal spot is enlarged primarily in the lateral direction, was developed. An electronically variable focus array transducer was also developed to enhance the throughput. An approach to treat a large volume of uterus myoma by coagulating its feeding arteries has been studied. The tissue volume to be coagulated can be thereby reduced by orders of magnitude. The penetration and throughput can potentially be improved at the same time by delivering a microbubble agent to the target tissue. It was theoretically predicted that a microbubble agent could multiply the ultrasonic tissue absorption. The effectiveness of this approach was confirmed in animal experiments using Optison. Real-time monitoring of tissue coagulation during HIFU exposure also can enhance the throughput through preventing excess deposition of ultrasonic energy. Monitoring coagulation by imaging local displacement in tissue with ultrasound will be discussed as well.

  15. Development of HIFU Therapy System for Lower Extremity Varicose Veins

    Science.gov (United States)

    Ota, Ryuhei; Suzuki, Jun; Yoshinaka, Kiyoshi; Deguchi, Juno; Takagi, Shu; Miyata, Tetsuro; Matsumoto, Yoichiro

    2009-04-01

    High-intensity focused ultrasound (HIFU) treatment utilizing microbubbles was investigated in the present study. It is known that microbubbles have the potential to enhance the heating effects of an ultrasound field. In this study, the heat accompanying microbubble oscillation was used to occlude varicose veins. Alteration of veins was observed after ultrasound irradiation. Veins were resected by stripping. In this study, two vein conditions were adopted during HIFU irradiation; non-compressed and compressed. Compressing the vein was expected to improve occlusion by rubbing the altered intima under compressed conditions. The frequency of the ultrasound was 1.7 MHz, the intensity at the focus was 2800 W/cm2, and the irradiation time was 20 s. In this study, the contrast agent Levovist® was chosen as a microbubble source, and the void fraction (ratio of total gas volume to liquid) in the vein was fixed at 10-5. Under non-compressed conditions, changes were observed only at the adventitia of the vein anterior wall. In contrast, under compressed conditions, changes were observed from the intima to the adventitia of both the anterior and posterior walls, and they were partly stuck together. In addition, more experiments with hematoxylin-eosin staining suggested that the changes in the vein were more substantial under the latter conditions. From these results, it was confirmed that the vein was occluded more easily with vein compression.

  16. Novel Non-invasive Treatment With High-intensity Focused Ultrasound (HIFU).

    Science.gov (United States)

    Marinova, M; Rauch, M; Schild, H H; Strunk, H M

    2016-02-01

    Ultrasound is not only used for diagnostic purposes but it also can be applied therapeutically so far that nowadays high-intensity focused ultrasound (HIFU) even represents a novel non-invasive treatment modality for various solid tumors. HIFU works by causing selectively deep tissue destruction of target lesions within the body without harming adjacent and overlying structures. In this article, we present an overview on both the mode of action and requirements for a HIFU treatment as well as on the safety and the current status of indications and possible applications with regard to benign and malignant gynecological diseases. Based on numerous studies and original articles, HIFU proved to be an effective and low-risk treatment option particularly for uterine fibroids and adenomyosis, but it also seems to be effective for breast fibroadenomas or even for breast cancer in special cases and other rare entities. PMID:26251996

  17. Research on the positioning problem in HIFU surgery platform application

    Institute of Scientific and Technical Information of China (English)

    XIANG Lin-qing; GAO Xue-guan; XU Jian-bo; MA Pei-sun

    2006-01-01

    For describing the positioning process of High Intensity Focused Ultrasound (HIFU) Surgery Platform in the application in tumor treatment, a simplified representation of the shape and location of the positioning target tumor in the workspace of the platform by the Positioning Volume Ellipsoid is designed; and the Nearest Neighbor Search method is used to find the closest center point of the simplified ellipsoid tumor model in a selected patient body surface point set determined by the motion parameter of the platform. By the query result the goal positioning path configuration and an intermediate positioning path configuration for the positioning motion are determined for the positioning motion planning. Three new criterions using distance change between Positioning Volume Ellipsoid and the Ultrasound Focus Ellipsoid are proposed to evaluate the result of the whole positioning procedure.

  18. Intra-operative Hemostasis of Punctured Femoral Artery Using HIFU: A Survival Study

    Science.gov (United States)

    Zderic, Vesna; Keshavarzi, Amid; Noble, Misty L.; Paun, Marla; Sharar, Sam R.; Crum, Lawrence A.; Martin, Roy W.; Vaezy, Shahram

    2005-03-01

    The objective was to investigate the long-term efficacy of hemostasis and healing of arteries after HIFU application. The femoral arteries of 22 adult rabbits were surgically exposed. Fifteen arteries were punctured with a needle and treated with HIFU, and 7 arteries were sham-treated (no puncture or HIFU was applied). The tip of the HIFU applicator was positioned on the bleeding site, and HIFU energy was applied until hemostasis was achieved. The focal intensity was approximately 3,000 W/cm2, at the resonant frequency of 9.6 MHz. Serial ultrasound images, blood and tissue samples were collected immediately and on days 1, 3, 7, 14, 28, and 60 after the treatment. Eleven of the arteries were patent after the treatment, and four arteries were occluded, as confirmed using Doppler imaging. One of the occluded arteries reopened at day 14. HIFU exposure time to achieve hemostasis was 27 ±17 seconds for patent arteries and 101±38 seconds for the occluded arteries. The blood flow velocities were not statistically different between HIFU-treated patent vessels and sham-treated vessels. The tunica adventitia and media, disrupted and coagulated immediately after the treatment, recovered to normal appearance within 28 days, with localized thinning of the tunica media observed up to day 60. Neo-intimal hyperplasia was observed in the arteries at days 14 and 28. HIFU produced an effective and long-term (up to 60 days) hemostasis of injured femoral arteries while preserving a normal blood flow and vessel wall structure in the majority of vessels.

  19. Study on Enhancement Effect of Cavitation Caused by HIFU Piezoelectricity Transducer

    Institute of Scientific and Technical Information of China (English)

    Xinnan Fan; Changping Zhu; Shichuan He; Minglei Shan; Jiacai Chen

    2006-01-01

    An orthogonal ultrasonic irradiation system consisting of HIFU with frequency at 1.05 MHz combined with ultrasound with frequency at 28 kHz was applied in this paper. Effect of cavitation was detected by pH-value measurement and conductance measurement. The result shows that the effect of cavitation caused by ultrasound with frequency at 28 kHz is greatly enhanced by HIFU piezoelectricity transducer with frequency at 1.05 MHz.

  20. First Experience Of Application Of High-Intensity Focused Ultrasonic Ablation (Hifu) In Prostate Cancer Treatment

    OpenAIRE

    A.V. Stativko; B.I. Blumberg; A.N. Ponukalin; R.N. Fomkin; P.V. Glybochko

    2009-01-01

    The scientific article points out that 40 sessions of HIFU prostate ablation have been performed for estimation of clinical efficiency. Average frequency of influences presents 628±164 impulses; average volume of tissues subjected to influence during one procedure is 33,8±16,3 smi (132 %) of prostate volume; average operation time constitutes 150 minutes (from 90 to 200 minutes). During the operation no complications have been occurred. In the first days after the session of HIFU there was a ...

  1. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Science.gov (United States)

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect. PMID:26585023

  2. Flat HIFU transducer with a sawtooth-shaped ultrasound radiation face

    Science.gov (United States)

    Son, Keon-Ho; Cho, Young-Ki; Kim, Dae-Seung; Kim, Myung-Deok; Kang, Kook-Jin

    2013-10-01

    High-intensity focused ultrasound (HIFU) transducers are spherically-curved in order to obtain a high intensity gain of the converged ultrasound energy at the geometrical focus. Ultrasound imaging devices monitor the procedure of HIFU treatment in ultrasound-guided HIFU systems where the image probe is positioned at the apex of the HIFU transducer, which has a spherical surface. However, the remote image probe's location yields a poor image quality compared to that obtained using conventional ultrasound imaging where the image probe is in direct contact with the surface. A phased array HIFU transducer with a new structure is suggested to overcome this limitation. The centers of the array elements are distributed over the flat surface of the transducer. However, the elements are tilted to form a geometrical focus, like a transducer with a spherically-curved surface, to obtain a high focal gain. The cross-section of the ultrasound radiation face of the transducer resembles the teeth of a saw. The acoustic field emitted from this transducer was simulated in order to design and produce the transducer. The simulation was compared with the measured sound field to verify that the transducer was correctly manufactured and designed; subsequently, the acoustic power was measured, and ultrasound images were obtained through the installation of an image probe on the transducer, which confirmed the application of this transducer to HIFU treatment.

  3. Segmentation of tumor ultrasound image in HIFU therapy based on texture and boundary encoding

    Science.gov (United States)

    Zhang, Dong; Xu, Menglong; Quan, Long; Yang, Yan; Qin, Qianqing; Zhu, Wenbin

    2015-02-01

    It is crucial in high intensity focused ultrasound (HIFU) therapy to detect the tumor precisely with less manual intervention for enhancing the therapy efficiency. Ultrasound image segmentation becomes a difficult task due to signal attenuation, speckle effect and shadows. This paper presents an unsupervised approach based on texture and boundary encoding customized for ultrasound image segmentation in HIFU therapy. The approach oversegments the ultrasound image into some small regions, which are merged by using the principle of minimum description length (MDL) afterwards. Small regions belonging to the same tumor are clustered as they preserve similar texture features. The mergence is completed by obtaining the shortest coding length from encoding textures and boundaries of these regions in the clustering process. The tumor region is finally selected from merged regions by a proposed algorithm without manual interaction. The performance of the method is tested on 50 uterine fibroid ultrasound images from HIFU guiding transducers. The segmentations are compared with manual delineations to verify its feasibility. The quantitative evaluation with HIFU images shows that the mean true positive of the approach is 93.53%, the mean false positive is 4.06%, the mean similarity is 89.92%, the mean norm Hausdorff distance is 3.62% and the mean norm maximum average distance is 0.57%. The experiments validate that the proposed method can achieve favorable segmentation without manual initialization and effectively handle the poor quality of the ultrasound guidance image in HIFU therapy, which indicates that the approach is applicable in HIFU therapy.

  4. Design and evaluation of a transesophageal HIFU probe for ultrasound-guided cardiac ablation: simulation of a HIFU mini-maze procedure and preliminary ex vivo trials.

    Science.gov (United States)

    Constanciel, Elodie; N'Djin, W Apoutou; Bessière, Francis; Chavrier, Françoise; Grinberg, Daniel; Vignot, Alexandre; Chevalier, Philippe; Chapelon, Jean Yves; Lafon, Cyril

    2013-09-01

    Atrial fibrillation (AF) is the most frequent cardiac arrhythmia. Left atrial catheter ablation is currently performed to treat this disease. Several energy sources are used, such as radio-frequency or cryotherapy. The main target of this procedure is to isolate the pulmonary veins. However, significant complications caused by the invasive procedure are described, such as stroke, tamponade, and atrioesophageal fistula, and a second intervention is often needed to avoid atrial fibrillation recurrence. For these reasons, a minimally-invasive device allowing performance of more complex treatments is still needed. High-intensity focused ultrasound (HIFU) can cause deep tissue lesions without damaging intervening tissues. Left atrial ultrasound-guided transesophageal HIFU ablation could have the potential to become a new ablation technique. The goal of this study was to design and test a minimally-invasive ultrasound-guided transesophageal HIFU probe under realistic treatment conditions. First, numerical simulations were conducted to determine the probe geometry, and to validate the feasibility of performing an AF treatment using a HIFU mini-maze (HIFUMM) procedure. Then, a prototype was manufactured and characterized. The 18-mm-diameter probe head housing contained a 3-MHz spherical truncated HIFU transducer divided into 8 rings, with a 5-MHz commercial transesophageal echocardiography (TEE) transducer integrated in the center. Finally, ex vivo experiments were performed to test the impact of the esophagus layer between the probe and the tissue to treat, and also the influence of the lungs and the vascularization on lesion formation. First results show that this prototype successfully created ex vivo transmural myocardial lesions under ultrasound guidance, while preserving intervening tissues (such as the esophagus). Ultrasound-guided transesophageal HIFU can be a good candidate for treatment of AF in the future. PMID:24658718

  5. Study on the application of digital signal processor (DSP) to adaptive control. 2. Active noise control to noise from a duct; DSP ni yoru tekio seigyo. 2. Duct kaikotan no soon eno active noise control

    Energy Technology Data Exchange (ETDEWEB)

    Kino, N.; Kitagawa, T.; Aoki, K. [Shizuoka Industrial Research Institute of Shizuoka prefecture, Shizuoka (Japan)

    1995-09-01

    Recent developments in signal processing technology, computer and LSI technology, especially DSP technology have made it possible to process sampled and quantized sound signals in real time. So sound field processing technology and sound field control technology have been made rapid progress. Active noise control technology is one of the sound field control technologies. And it can be applied to low frequency noise reduction problems that we couldn`t cope with in usual way. So we developed an experimental device of active noise control. We report how we developed this device and refer to the experimental results about a random frequency noise in this report. 5 refs., 18 figs., 1 tab.

  6. Nanoparticle-enhanced synergistic HIFU ablation and transarterial chemoembolization for efficient cancer therapy

    Science.gov (United States)

    You, Yufeng; Wang, Zhigang; Ran, Haitao; Zheng, Yuanyi; Wang, Dong; Xu, Jinshun; Wang, Zhibiao; Chen, Yu; Li, Pan

    2016-02-01

    High-intensity focused ultrasound (HIFU) is being generally explored as a non-invasive therapeutic modality to treat solid tumors. However, the clinical use of HIFU for large and deep tumor-ablation applications such as hepatocellular carcinoma (HCC) is currently entangled with long treatment duration and high operating energy. This critical issue can be potentially resolved by the introduction of HIFU synergistic agents (SAs). Traditional SAs such as microbubbles and microparticles face the problem of large size, short cycle time, damage to mononuclear phagocytic system and unsatisfactory targeting efficiency. In this work, we have developed a facile and versatile nanoparticle-based HIFU synergistic cancer surgery enhanced by transarterial chemoembolization for high-efficiency HCC treatment based on elaborately designed Fe3O4-PFH/PLGA nanocapsules. Multifunctional Fe3O4-PFH/PLGA nanocapsules were administrated into tumor tissues via transarterial injection combined with Lipiodol to achieve high tumor accumulation because transarterial chemoembolization by Lipiodol could block the blood vessels. The high synergistic HIFU ablation effect was successfully achieved against HCC tumors based on the phase-transformation performance of the perfluorohexane (PFH) inner core in the composite nanocapsules, as systematically demonstrated in VX2 liver tumor xenograft in rabbits. Multifunctional Fe3O4-PFH/PLGA nanocapsules were also demonstrated as efficient contrast agents for ultrasound, magnetic resonance and photoacoustic tri-modality imagings, potentially applicable for imaging-guided HIFU synergistic surgery. Therefore, the elaborate integration of traditional transarterial chemoembolization with recently developed nanoparticle-enhanced HIFU cancer surgery could efficiently enhance the HCC cancer treatment outcome, initiating a new and efficient therapeutic protocol/modality for clinic cancer treatment.

  7. Robotic high-intensity focused ultrasound (rHIFU) for the prostate cancer treatment

    Science.gov (United States)

    Solovov, Vyacheslav; Shaplygin, Leonid; Vozdvizhenskiy, Mikhail

    2012-11-01

    Introduction & Objectives: rHIFU shows a successful treatment for localized prostate cancer (PC). Here we explored the effectiveness of the rHIFU treatment for the prostate cancer, hormone-resistant prostate cancer (HRPC) and failure after external beam radiotherapy (EBRT) and radical prostatectomy (RPE). Materials & Methods: 748 patients were treated in our center between Sep 2007 - February 2012: 137 - hormone-resistance (median time before hormone-resistance 25 months), 286 - received neoadjuvant hormone therapy 6 months, 293 - no treatment before HIFU, 32 - after the EBRT failure. 667 patients underwent TURP+rHIFU, 81 only rHIFU (volume prostate prostate volume - 39 (5,5-108) cc. Results: Median PSA level 12 months after rHIFU treatment were 0,04 (0-2,24) ng/ml - low risk group, for high risk group - 0,5 (0-48,4) ng/ml, with failure after EBRT and RPE- 0,5 (0-3,2) ng/ml; 36 months after rHIFU treatment were 0,5 (0,02-3,6) ng/ml - low risk group, for high risk group - 3,2 (0-21,38) ng/ml, with failure after EBRT and RPE - 1,7 (0-9,8) ng/ml. Patients with low risk had 4,5% of progression, with high risk PC - 25%, with failure after EBRT and RPE - 19,6%. Kaplan-Meir analyses of the total group indicated that the risk of progression after 1 year follow-up was 10%, the risk of progression was 23% after 4 years of follow-up. Complications: incontinence I - 17,5%, incontinence II - 7,7%, stricture - 18,2%, fistula - 0,3 %. Conclusions: Our experience shows that rHIFU ablation is safe, minimally invasive, effective treatment with moderate side effects for the PC, hormone-resistant prostate cancer, rHIFU also may be used as a salvage therapy after EBRF. Further studies are required.

  8. Sonablate-500TM Transrectal High-intensity Focused Ultrasound (HIFU) for Benign Prostatic Hyperplasia Patients

    Institute of Scientific and Technical Information of China (English)

    L(U) Jun; HU Weilie; WANG Wei; ZHANG Yuanfeng; CHEN Zhaoyang; YE Zhangqun

    2007-01-01

    To evaluate the safety and efficacy of transrectal high-intensity focused ultrasound (HIFU) in the treatment of benign prostatic hyperplasia (BPH), serial studies were conducted in 150 BPH pa- tients before and 30 min, 1, 2, 6 and 12 month(s) after Sonablate-500TM HIFU treatment. A sili- con-coated indwelling 16F latex catheter was placed during the determination of the therapy zone. Preoperative and postoperative evaluations were made by using the international prostate symptom score (IPSS), quality of life (QOL), uroflowmetric findings and transrectal ultrasound, and incidence of complications. The cystourethrography was done in 23 patients within 1 year postoperatively. The results showed that after HIFU treatment, IPSS and QOL scores were significantly decreased at 1, 2, 6 and 12 month(s) (P<0.01). Maximum urine flow rate (6.0 to 17.2 mL/s, P<0.01), PVR (75.0 to 30.3,P<0.01) and prostatic volume (65.0 to 38.1 mL, P<0.05) were significantly improved 12 months after the operation. Recurrent urinary retention (n=2) and urethrorectal fistula (n=1) occurred at the 15th postoperative day. The duration of the HIFU prostate ablation was 25-90 rain. The mean time for an indwelling catheter was 3-19 days. These data demonstrate that treatment of BPH with Sonab- late-500TM HIFU is safe and effective.

  9. Interactions H.I.F.U. / polymer films

    Science.gov (United States)

    Hallez, L.; Touyeras, F.; Hihn, J.-Y.; Bailly, Y.

    2010-01-01

    In order to obtain the modification of a defined volume of a polymer layer, preliminary tests of sonication (HIFU 0.75 and 3 MHz) were carried out to obtain an accurate characterization of the acoustic fields as well as convective flow velocities measured close to the surface by Particle Image Velocimetry and luminol mapping. Then, sonication of a delimited zone of an acrylic resin deposited upon a stainless steel thin substrate highlighted a strong dependence of the polymerization or reticulation degree, with different exposure times and different power thresholds for the same final modification. The point was to examine the ability of the thin polymer film to absorb ultrasonic energy or to act as a perfect reflector which induces asymmetric cavitation and therefore violent collapses to take place close to the surface. In the first case, the wave absorption by the film is converted into heat and then acts for the polymer alteration under the high convective flow velocities. For the highest acoustic intensities and for the hardest films, cavitation occurs and the produced microbubbles oscillated and grow close to the surface. Then, the shocks resulting of the bubble collapse eroded mechanically the film.

  10. A new experimental study on noninvasive thermometry in HIFU

    Institute of Scientific and Technical Information of China (English)

    侯珍秀; 徐祯祥; 金长善

    2002-01-01

    The measurement of temperature at the heated point is very important and difficult for the treatmentof tumor using HIFU( High intensity focused ultrasound). According to the theory that the gray scale value va-ries with the ultrasound transmitting through different tissues at different temperatures, a set of experiment e-quipment was designed to describe the temperature field in tissues by using the characteristics of the ultrasonicimage, and an experiment was carried out with fresh liver and muscle tissues of pigs in a temperature arrange of26 ℃ to 64 ℃. The statistical curve of the experiment demonstrates: ( 1 ) The gray scales vary in accordancewith the changes in the temperature of tissue and it is feasible to measure the temperature at the heated point bymaking use of the gray scale variations; (2) Non-linearity is the characteristics of temperature changes and thegray scale of tissues at different temperature phases. Moreover, the gray scale varies from up to down phase atthe same temperature phase; ( 3 ) The gray scale for the same temperature range varies with different tissues. Anexperimented formula is proposed for the measurement of fresh liver and muscle tissues of pigs.

  11. Salvage HIFU for biopsy confirmed local prostate cancer recurrence after radical prostatectomy and radiation therapy: Case report and literature review.

    Science.gov (United States)

    Rittberg, Rebekah; Kroczak, Tadeusz; Fleshner, Neil; Drachenberg, Darrel

    2015-01-01

    High-intensity focused ultrasound (HIFU) is a treatment option for low- and intermediate-risk prostate cancer and more recently has been used as salvage therapy after failed radiation therapy. We present a case of local recurrence with biochemical failure after radical prostatectomy and salvage external beam radiation therapy with salvage HIFU without biochemical recurrence at 20 months. PMID:26425239

  12. Salvage HIFU for biopsy confirmed local prostate cancer recurrence after radical prostatectomy and radiation therapy: Case report and literature review

    OpenAIRE

    Rittberg, Rebekah; Kroczak, Tadeusz; Fleshner, Neil; Drachenberg, Darrel

    2015-01-01

    High-intensity focused ultrasound (HIFU) is a treatment option for low- and intermediate-risk prostate cancer and more recently has been used as salvage therapy after failed radiation therapy. We present a case of local recurrence with biochemical failure after radical prostatectomy and salvage external beam radiation therapy with salvage HIFU without biochemical recurrence at 20 months.

  13. Feasibility of laser-integrated high intensity focused ultrasound (HIFU) treatment for bladder tumors: in vitro study (Conference Presentation)

    Science.gov (United States)

    Nguyen, Van Phuc; Park, Suhyun; Oh, Junghwan; Kang, Hyun Wook

    2016-02-01

    Previous studies have shown that photothemal therapy combined with high intensity focused ultrasound (HIFU) can provide a promising method to achieve rapid thermal coagulation during surgical procedures. The current study investigated the feasibility of the laser-integrated high intensity focused ultrasound (HIFU) application to treat bladder tumors by enhancing thermal effects and therapeutic depth in vitro. To generate thermal coagulation, a single element HIFU transducer with a central frequency of 2.0 MHz was used to transmit acoustic energy to 15 fresh porcine bladders injected with an artificial tumor (100 µl gelatin and hemoglobin solution) in vitro. Simultaneously, an 80-W 532-nm laser system was also implemented to induce thermal necrosis in the targeted tissue. The intensity of 570 W/cm2 at the focus of HIFU and laser energy of 0.9 W were applied to all the samples for 40 s. The temperature rise increased up to about 1.6 or 3 folds (i.e., ΔT=32±3.8 K for laser-integrated HIFU, ΔT=20±6.5 K for HIFU only, and ΔT=11±5.6 K for laser only). The estimated lesion depth also increased by 1.3 and 2 folds during the dual-thermal treatment, in comparison with the treatment by either HIFU or laser. The results indicated that the laser-integrated HIFU treatment can be an efficient hyperthermic method for tumor coagulation.

  14. The Efficacy of High-Intensity Focused Ultrasound (HIFU) in Advanced Pancreatic Cancer

    Institute of Scientific and Technical Information of China (English)

    Bo Xie; Jiajun Ling; Weiming Zhang; Xueqin Huang; Jihua Zhen; Yanzhe Huang

    2008-01-01

    OBJECTIVE To observe the efficacy of high-intensity focused ultrasound (HIFU)in the treatment of late-stage pancreatic cancer.METHODS Sixteen patients with advanced pancreatic cancer received HIFU therapy.Evaluation of efficacy was made on the basis of changes in clinical symptoms and variations in the tumor echo and size.RESULTS Clinical symptoms such as pain were significantly alleviated,echo of the tumor was enhanced with B-US and the quality of life such as eating,sleeping and mental status was markedly improved;no serious complications were observed.CONCLUSION The use of HIFU in the treatment of advanced pancreatic cancer is feasible and safe.It is effective in killing the carcinoma cells and alleviaring pain.This technique may offer non-invasive therapy for the treatment of patients with late-stage pancreatic cancer.

  15. Sonoluminescence characterization of inertial cavitation inside a BSA phantom treated by pulsed HIFU.

    Science.gov (United States)

    Yin, Hui; Chang, Nan; Xu, Shanshan; Wan, Mingxi

    2016-09-01

    The aim of this study was to investigate the inertial cavitation inside a phantom treated by pulsed HIFU (pHIFU). Basic bovine serum albumin (BSA) phantoms without any inherent ultrasound contrast agents (UCAs) or phase-shift nano-emulsions (PSNEs) were used. During the treatment, sonoluminescence (SL) recordings were performed to characterize the spatial distribution of inertial cavitation adjacent to the focal region. High-speed photographs and thermal coagulations, comparing with the SL results, were also recorded and presented. A series of pulse parameters (pulse duration (PD) was between 1 and 23 cycles and pulse repetition frequency (PRF) was between 0.5kHz and 100kHz) were performed to make a systematic investigation under certain acoustic power (APW). Continuous HIFU (cHIFU) investigation was also performed to serve as control group. It was found that, when APW was 19.5W, pHIFU with short PD was much easier to form SL adjacent to the focal region inside the phantom, while it was difficult for cHIFU to generate cavitation bubbles. With appropriate PD and PRF, the residual bubbles of the previous pulses could be stimulated by the incident pulses to oscillate in a higher level and even violently collapse, resulting to enhanced physical thermogenesis. The experimental results showed that the most violent inertial cavitation occurs when PD was set to 6 cycles (5μs) and PRF to 10kHz, while the highest level of thermal coagulation was observed when PD was set to 10 cycles. The cavitational and thermal characteristics were in good correspondence, exhibiting significant potentiality regarding to inject-free cavitation bubble enhanced thermal ablation under lower APW, compared to the conventional thermotherapy. PMID:27150756

  16. Characterization of HIFU ablation using DNA fragmentation labeling as apoptosis stain

    Science.gov (United States)

    Anquez, Jeremie; Corréas, Jean-Michel; Pau, Bernard; Lacoste, François; Yon, Sylvain

    2012-11-01

    The goal of this work was to compare modalities to precisely quantify the extent of thermally induced lesions: gross pathology vs. histopathology vs. devascularization. Liver areas of 14 rabbits were targeted with HIFU and RF ablations in an acute study. Contrast enhanced computorized tomography (CE-CT) scan images were acquired two hours after HIFU and RF treatment to obtain the devascularized volumes of the livers. The animals were then euthanized and deep frozen. The livers were sliced and each slice was photographed and stacked yielding a volume of gross pathology. The volume VGP of the HIFU lesions were derived. The area AGP of the lesions were computed on a particular slice. The lesions were segmented as hypo intense (devascularized) regions on CE-CT images and their volumes VC were computed. The ratios VC/VGP were computed for all the HIFU lesions on all the 14 subjects with a mean value of 1.2. Histology was performed on the livers using Hematoxyline Eosine Staining (HES) and DNA Fragmentation labeling (TUNEL® technology) which characterizes apoptosis. Apoptotic regions of area AT were segmented on the images stained by TUNEL®. No necrosis was identified on the HES data. While TUNEL® did not mark the cores of the RF lesions as apoptotic, the periphery of HIFU and RF lesions was always recognized with TUNEL® as apoptotic. The ratio AGP/AT was computed. The mean value was 0.95 and 0.25 for HIFU and RF lesions respectively. These findings show that the devascularized territory seen on CE-CT scan coincide with the coagulated territories seen with gross pathology. Those actually correspond to cells in apoptosis. It is confirmed that HES stain does not show necrosis 2 hours after thermal ablation. TUNEL® technology for DNA fragmentation labeling appears as a useful marker for thermally induced acute lesions in the liver.

  17. A Pulsatile Flow Phantom for Image-Guided HIFU Hemostasis of Blood Vessels

    Science.gov (United States)

    Greaby, Robyn; Vaezy, Shahram

    2005-03-01

    A pulsatile flow phantom for studying ultrasound image-guided acoustic hemostasis in a controlled environment has been developed. An ex vivo porcine carotid artery was attached to the phantom and embedded in a visually and ultrasonically transparent gel. Heparinized porcine blood was pumped through the phantom. Power-Doppler and B-mode ultrasound were used to remotely target the HIFU focus to the site of a needle puncture. In nine trials, complete hemostasis was achieved after an average HIFU application of 55 +/- 34 seconds. The vessels remained patent after treatment. With this phantom, it will be possible to do controlled studies of ultrasound image-guided acoustic hemostasis.

  18. Multideimensional adaptive filtering for noise reduction in computerized tomography. Comparison and combination of convolution based and spline based approaches; Multidimensionale adaptive Filterung zur Rauschreduktion in der Computertomographie. Vergleich und Kombination faltungs- und splinebasierter Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Henke, Maria

    2009-07-01

    Since a few years there is the possibility of tomographic imaging with a C-Arm-system in addition to the conventional X-ray-computed tomography. By the use of a flatpanel detector the C-Arm-CT offers a high isotropic resolution. Besides the reduction of dose the improvement of image quality is on the top of the user's list of wishes. To improve the image quality at constant dose or allow dose reduction at changeless image quality methods of noise reduction are used in conventional CT-imaging. To reduce overall measurement- and reconstruction-time so-called on-line-compliant systems are developed which start reconstruction before the measurement is competed. The aim of this work is the development of algorithms for noise reduction in projection data which shall be applied especially to flatpanel-CT and fit in into online-compliant systems. Among the so far known noise reduction methods are the convolution based multidimensional adaptive filtering by Kachelries, Watzke and Kalender (MAF{sup KWK}) and the spline and statistic based filtering by La Riviere and Billmire (SSAF{sup RB}). The former can not be applied for on-line-reconstruction, the latter can be applied to one-dimensional data only. Both methods are developed further to overcome these restrictions. In addition a hybrid method from a combination of a convolution based and the spline and statistic approach is developed. The impact of the algorithms to noise and resolution is characterized using so-called {sigma}-FWHM-curves from simulated and measured one- and two-dimensional data, respectively. The change in noise impression and structure is considered by means of slices. Examples of the application to clinical data rounds out the comparison. The results of this work are a new convolution based adaptive filtering (CAF), which is on-line-compliant, a spline and statistic based filtering for two-dimensional data (SSAF{sup B2d}) and a hybrid method (Hybrid{sup CAF}). These new adaptive algorithms for

  19. 管道低频噪声的自适应有源控制%Adaptive Active Control of Low-Frequency Noise in a Duct

    Institute of Scientific and Technical Information of China (English)

    李传光; 李悟; 韩秀苓

    1999-01-01

    目的针对实际的具有行波的管道模型,研究一种降噪方案.方法通过建立数学模型和用来导出降噪的自适应系统的传递函数,对RLS、LMS和LSL算法的效果进行分析和比较.结果不存在声反馈时,对0-500Hz的宽带噪声可达到平均降噪量(MNRV)27.5dB.若存在声反馈并使用气流扬声器时,MNRV只有近似4.9dB.当该扬声器具有平坦特性时,MNRV可提高10.2dB.结论这项抵消技术可用于对排气管降噪.原则上,它亦可用于三维封闭空间的降噪问题.%Aim To study a method realizing noise control for a physical model of progressive wave in a duct. Methods A mathematical model was constructed and a transfer function of the adaptive system for noise control was also worked out; moreover, the effects of some algorithms such as RLS,LMS and LSL on noise control were analyzed and compared. Results Without the feedback of sound, the mean noise reduce value(MNRV) of 27.5 dB for broadband noise from 0 to 500Hz in frequency were achieved. When acoustic feedback took place and an air-stream loudspeaker was used, the MNRV was only about 4.9dB. But if the loudspeaker had a plain frequency feature, MNRV was improved by 10.2dB. Conclusion The technique is applied to ruducing the noise from engines' exhausted gas pipes. It is, in principle, used for noise-cancelling in a closed three dimensional space.

  20. A new HIFU probe for the treatment of the superficial venous insufficiency and varicose veins

    Science.gov (United States)

    Pichardo, Samuel; Curiel, Laura; Milleret, René; Pichot, Olivier; Lacoste, François; Chapelon, Jean-Yves

    2006-05-01

    A previous work showed the feasibility of inducing a localized partial shrinkage of venous tissues with High Intensity Focused Ultrasound (HIFU). A partial shrinkage of the vein wall is proposed to correct the valvular dysfunction on the saphenous vein that is responsible of the superficial venous insufficiency and varicose veins. In the present study, a new real-time imaging HIFU probe is presented which is suited for this type of treatment. The probe is composed of two HIFU elements that focus sound uniformly over a line of 7 mm-length. Geometry of the HIFU elements was calculated by numerical optimization and allows positioning of the focal line 15 mm in-depth from the skin. The probe is compatible with commercial imaging devices used currently in vascular medicine. Once coupled with an imaging probe, the imaging system shows the central perpendicular plan to the focal line. A validation of the compatibility with a commercial ultrasound imaging system was achieved using a precise model fabricated by stereo-lithography. Construction of the probe is underway.

  1. Identification of risk factors of prostate adenocarcinoma recurrence after HIFU therapy using immunohistochemical markers

    Directory of Open Access Journals (Sweden)

    Popkov V.M.

    2014-12-01

    Full Text Available The purpose of this study was to identify risk factors for recurrence of prostate adenocarcinoma after HIFU therapy. Material and methods: Material for the study was obtained from patients diagnosed with adenocarcinoma before and after HIFU treatment. Morphological study was conducted using a standard staining, and immunohistochemical markers: PCNA, Amacr, E-cadherin, Bel2, Andr, Estr, VEGF, P53, PCNA. Results: After treatment in 89% of patients with initial prostate volume greater than 50 cc the signs of recurrence of adenocarcinoma were showed. At low risk for D'Amico after treatment the expression of proliferation markers, VEGF, Amacr significantly decreased. With a high degree of risk — increased expression of Bel2. After treatment the expression of the following markers: PCNA, Amacr, VEGF significantly increased in the group of patients with the presence of invasion. Conclusion: Patients with initial prostate volume less than 50 cc, low risk to D'Amico, the lack of perineural and perivascular invasion have a low risk of recurrence after HIFU therapy; patients at high risk for D'Amico, the presence of perineural and perivascular invasion initial and prostate volume greater than 50 cc, low-grade cribriform form of adenocarcinoma have a high risk of recurrence of adenocarcinoma. Recurrence of adenocarcinoma develops independently of the period after HIFU therapy.

  2. Significant skin burns may occur with the use of a water balloon in HIFU treatment

    Science.gov (United States)

    Ritchie, Robert; Collin, Jamie; Wu, Feng; Coussios, Constantin; Leslie, Tom; Cranston, David

    2012-10-01

    HIFU is a minimally-invasive therapy suitable for treating selected intra-abdominal tumors. Treatment is safe although skin burns may occur due to pre-focal heating. HIFU treatment of a renal transplant tumor located in the left lower abdomen was undertaken in our centre. Treatment was performed prone, requiring displacement of the abdominal wall away from the treatment field using a water balloon, constructed of natural rubber latex and filled with degassed water. Intra-operatively, ultrasound imaging and physical examination of the skin directly over the focal region was normal. Immediately post-operative, a full-thickness skin burn was evident at the periphery of the balloon location, outside the expected HIFU path. Three possibilities may account for this complication. Firstly, the water balloon may have acted as a lens, focusing the HIFU to a neo-focus off axis. Secondly, air bubbles may have been entrapped between the balloon and the skin, causing heating at the interface. Finally, heating of the isolated water within the balloon may have been sufficient to cause burning. In this case, the placement of a water balloon caused a significant skin burn. Care should be taken in their use as burns, situated off axis, may occur even if the overlying skin appears normal.

  3. Initial Experience with the Extracorporeal HIFU Knife with 49 Patients: Japanese Experience

    Science.gov (United States)

    Ganaha, F.; Okuno, T.; Lee, C. O.; Shimizu, T.; Osako, K.; Oka, S.; Lee, K. H.; Chen, W. Z.; Zhu, H.; Park, S. H.; Qi, Z.; Shi, D.; Song, H. S.

    2005-03-01

    Forty nine patients with 63 tumours were treated with the Chongqing Haifu knife, as an adjunct to intra-arterial chemoinfusion. Treatment targets included breast (20 lesions), liver (16), bone (8), lymph-node (6), soft tissue (4), lung and pleura (4), pancreas (2), kidney (2) and adrenal gland (1). Follow-up contrast MRI was performed at 3 weeks to assess the effects of HIFU ablation. All cases completed the planned treatment. Of 25 lesions treated with the intention of complete tumour ablation, complete necrosis was obtained in 19 lesions (76%) including 4 secondary success cases. Among 32 lesions having partial and palliative treatment, tumour size was decreased in 6 lesions (21%), and good pain control was obtained in 6 out of 7 patients (86%). Skin injury was the most common complication after HIFU (16%), and was mostly a superficial dermal burn that did not necessitate any treatment. However, there was one patient with deep skin injury at an operation scar which resulted in skin perforation. Other adverse events included soft tissue swelling, prolonged fever, anorexia, persistent pain, shortness of the breath, sacroiliac joint fracture and prolonged diarrhoea. In our limited experience, superficial lesions (e.g. breast cancer, bone, soft tissue, lymph-node and pleural metastasis) appear to be good candidates for HIFU treatment. There appears to be a role for the HIFU knife in pain control for patients with bone metastasis and pancreatic cancer.

  4. Adapt

    Science.gov (United States)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  5. Evidence for a new mechanism behind HIFU-triggered release from liposomes.

    Science.gov (United States)

    Oerlemans, Chris; Deckers, Roel; Storm, Gert; Hennink, Wim E; Nijsen, J Frank W

    2013-06-28

    A promising approach for local drug delivery is high-intensity focused ultrasound (HIFU)-triggered release of drugs from stimuli-responsive nanoparticles such as liposomes. The aim of this study was to investigate whether another release mechanism is involved with HIFU-triggered release from liposomes beside cavitation and temperature. Furthermore, it was studied whether this new release mechanism allows the release of lipophilic compounds. Therefore, both a lipophilic (Nile red) and a hydrophilic (fluorescein) compound were loaded into thermosensitive (TSL) or non-thermosensitive liposomes (NTSL) and the liposomes were subjected both to continuous wave (CW)- and pulsed wave (PW)-HIFU. The mean liposome size varied from 97 to 139 nm with a polydispersity index (PDI)≤0.06 for the different formulations. The Tm of the phospholipid bilayer of the TSL was around 42°C. Approximately 80% of fluorescein was released within 15 min from TSL at temperatures≥42°C. In contrast, no fluorescein release from NTSL and NR release from both TSL and NTSL was observed at temperatures up to 60 °C. CW-HIFU exposure of TSL resulted in rapid temperature elevation up to 52°C and subsequently almost quantitative fluorescein release. Fluorescein release from NTSL was also substantial (~64% after 16 min at 20 W). Surprisingly, CW-HIFU exposure (20W for 16 min) resulted in the release of NR from TSL (~66% of the loaded amount), and this was even higher from NTSL (~78%). PW-HIFU exposure did not result in temperatures above the Tm of TSL. However, nearly 85% of fluorescein was released from TSL after 32 min at 20W of PW-HIFU exposure, whereas the release from NTSL was around 27%. Interestingly, NR release from NTSL was~30% after 2 min PW-HIFU exposure and increased to~70% after 32 min. Furthermore, addition of microbubbles to the liposomes prior to PW-HIFU exposure did not result in more release, which suggests that cavitation can be excluded as the main mechanism responsible for the

  6. Effects of oxytocin on high intensity focused ultrasound (HIFU) ablation of adenomysis: A prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Zou, Min; Zhang, Cai [Department of Obstetrics and Gynecology, Chongqing Haifu Hospital, Chongqing 401121 (China); He, Jia [Department of Obstetrics and Gynecology, Suining Central Hospital, Sichuan 629000 (China); Mao, Shihua [Department of Obstetrics and Gynecology, Three Gorges Central Hospital, Chongqing 404000 (China); Wu, Qingrong [Department of Obstetrics and Gynecology, Fuling Central Hospital, Chongqing 408099 (China); He, Min [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Department of Obstetrics and Gynecology, Suining Central Hospital, Sichuan 629000 (China); Wang, Jian [Department of Obstetrics and Gynecology, Chongqing Haifu Hospital, Chongqing 401121 (China); Department of Obstetrics and Gynecology, Three Gorges Central Hospital, Chongqing 404000 (China); Zhang, Ruitao [Department of Obstetrics and Gynecology, Chongqing Haifu Hospital, Chongqing 401121 (China); Department of Obstetrics and Gynecology, Fuling Central Hospital, Chongqing 408099 (China); Zhang, Lian, E-mail: lianwzhang@yahoo.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Department of Obstetrics and Gynecology, Chongqing Haifu Hospital, Chongqing 401121 (China)

    2014-09-15

    Objective: To investigate the effects of oxytocin on high-intensity focused ultrasound (HIFU) ablation for the treatment of adenomyosis. Materials and methods: Eighty-six patients with adenomyosis from three hospitals were randomly assigned to the oxytocin group or control group for HIFU treatment. During HIFU treatment, 80 units of oxytocin was added in 500 ml of 0.9% normal saline running at the rate of 2 ml/min (0.32 U/min) in the oxytocin group, while 0.9% normal saline was used in the control group. Both patients and HIFU operators were blinded to oxytocin or saline application. Treatment results, adverse effects were compared. Results: When using oxytocin, the non-perfused volume (NPV) ratio was 80.7 ± 11.6%, the energy-efficiency factor (EEF) was 8.1 ± 9.9 J/mm{sup 3}, and the sonication time required to ablate 1 cm{sup 3} was 30.0 ± 36.0 s/cm{sup 3}. When not using oxytocin, the non-perfused volume ratio was 70.8 ± 16.7%, the EEF was 15.8 ± 19.6 J/mm{sup 3}, and the sonication time required to ablate 1 cm{sup 3} was 58.2 ± 72.7 S/cm{sup 3}. Significant difference in the NPV ratio, EEF, and the sonication time required to ablate 1 cm{sup 3} between the two groups was observed. No oxytocin related adverse effects occurred. Conclusion: Oxytocin could significantly decrease the energy for ablating adenomyosis with HIFU, safely enhance the treatment efficiency.

  7. Effects of oxytocin on high intensity focused ultrasound (HIFU) ablation of adenomysis: A prospective study

    International Nuclear Information System (INIS)

    Objective: To investigate the effects of oxytocin on high-intensity focused ultrasound (HIFU) ablation for the treatment of adenomyosis. Materials and methods: Eighty-six patients with adenomyosis from three hospitals were randomly assigned to the oxytocin group or control group for HIFU treatment. During HIFU treatment, 80 units of oxytocin was added in 500 ml of 0.9% normal saline running at the rate of 2 ml/min (0.32 U/min) in the oxytocin group, while 0.9% normal saline was used in the control group. Both patients and HIFU operators were blinded to oxytocin or saline application. Treatment results, adverse effects were compared. Results: When using oxytocin, the non-perfused volume (NPV) ratio was 80.7 ± 11.6%, the energy-efficiency factor (EEF) was 8.1 ± 9.9 J/mm3, and the sonication time required to ablate 1 cm3 was 30.0 ± 36.0 s/cm3. When not using oxytocin, the non-perfused volume ratio was 70.8 ± 16.7%, the EEF was 15.8 ± 19.6 J/mm3, and the sonication time required to ablate 1 cm3 was 58.2 ± 72.7 S/cm3. Significant difference in the NPV ratio, EEF, and the sonication time required to ablate 1 cm3 between the two groups was observed. No oxytocin related adverse effects occurred. Conclusion: Oxytocin could significantly decrease the energy for ablating adenomyosis with HIFU, safely enhance the treatment efficiency

  8. Noise suppression by noise

    OpenAIRE

    Vilar, J. M. G.; Rubí Capaceti, José Miguel

    2001-01-01

    We have analyzed the interplay between an externally added noise and the intrinsic noise of systems that relax fast towards a stationary state, and found that increasing the intensity of the external noise can reduce the total noise of the system. We have established a general criterion for the appearance of this phenomenon and discussed two examples in detail.

  9. Noise reduction of dental drill noise

    OpenAIRE

    Rotter, KRGR; Atherton, MA; Kaymak, E; Millar, BJ

    2008-01-01

    Dental drills produce a characteristic noise that is uncomfortable for patients and is also known to be harmful to dentists under prolonged exposure. It is therefore desirable to protect the patient and dentist whilst allowing two-way communication, which will require a headphone - type system. Re-establishing good communication between the dentist and patient will be achieved through a combination of three noise cancellation technologies, namely, Passive Noise Control (PNC), Adaptive Filteri...

  10. High Intensity Focused Ultrasound (HIFU) as a Salvage Treatment for Recurrent Prostate Cancer after Brachytherapy — a Feasibility Study

    Science.gov (United States)

    Chapman, Alexander T.; Rivens, Ian H.; Thompson, Alan C.; ter Haar, Gail R.

    2007-05-01

    HIFU may be an effective salvage treatment for patients who develop local recurrence after permanent low-dose brachytherapy. It has been suggested that the presence of seeds in the prostate may obstruct the HIFU beam or alter the heating characteristics of the prostate tissue. Acoustic field measurements were made using a membrane hydrophone and lesioning experiments were carried out in ex vivo bovine liver. These revealed a significant effect of the seeds on the HIFU focal region as well as a reduction in lesion length when seeds were placed in a pre-focal position. Further work is needed to evaluate the full effects of implanted brachytherapy seeds on the clinical delivery of HIFU.

  11. Effect of hydrodynamic cavitation in the tissue erosion by pulsed high-intensity focused ultrasound (pHIFU)

    Science.gov (United States)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2016-09-01

    High-intensity focused ultrasound (HIFU) is emerging as an effective therapeutic modality in clinics. Besides the thermal ablation, tissue disintegration is also possible because of the interaction between the distorted HIFU bursts and either bubble cloud or boiling bubble. Hydrodynamic cavitation is another type of cavitation and has been employed widely in industry, but its role in mechanical erosion to tissue is not clearly known. In this study, the bubble dynamics immediately after the termination of HIFU exposure in the transparent gel phantom was captured by high-speed photography, from which the bubble displacement towards the transducer and the changes of bubble size was quantitatively determined. The characteristics of hydrodynamic cavitation due to the release of the acoustic radiation force and relaxation of compressed surrounding medium were found to associate with the number of pulses delivered and HIFU parameters (i.e. pulse duration and pulse repetition frequency). Because of the initial big bubble (~1 mm), large bubble expansion (up to 1.76 folds), and quick bubble motion (up to ~1 m s-1) hydrodynamic cavitation is significant after HIFU exposure and may lead to mechanical erosion. The shielding effect of residual tiny bubbles would reduce the acoustic energy delivered to the pre-existing bubble at the focus and, subsequently, the hydrodynamic cavitation effect. Tadpole shape of mechanical erosion in ex vivo porcine kidney samples was similar to the contour of bubble dynamics in the gel. Liquefied tissue was observed to emit towards the transducer through the punctured tissue after HIFU exposure in the sonography. In summary, the release of HIFU exposure-induced hydrodynamic cavitation produces significant bubble expansion and motion, which may be another important mechanism of tissue erosion. Understanding its mechanism and optimizing the outcome would broaden and enhance HIFU applications.

  12. Annular and Cylindrical Phased Array Geometries for Transrectal High-Intensity Focused Ultrasound (HIFU) using PZT and Piezocomposite Materials

    Science.gov (United States)

    Seip, Ralf; Chen, Wohsing; Carlson, Roy; Frizzell, Leon; Warren, Gary; Smith, Nadine; Saleh, Khaldon; Gerber, Gene; Shung, Kirk; Guo, Hongkai; Sanghvi, Narendra T.

    2005-03-01

    This paper presents engineering progress and the latest in-vitro and in-vivo results obtained with a 4.0 MHz, 20 element, PZT annular transrectal HIFU array and several 4.0 MHz, 211 element, PZT and piezocomposite cylindrical transrectal HIFU arrays for the treatment of prostate cancer. The geometries of both arrays were designed and analyzed to steer the HIFU beams to the desired sites in the prostate volume using multi-channel electronic drivers, with the intent to increase treatment efficiency and reliability for the next generation of HIFU systems. The annular array is able to focus in depth from 25 mm to 50 mm, generate total acoustic powers in excess of 60W, and has been integrated into a modified Sonablate®500 HIFU system capable of controlling such an applicator through custom treatment planning and execution software. Both PZT- and piezocomposite cylindrical arrays were constructed and their characteristics were compared for the transrectal applications. These arrays have been installed into appropriate transducer housings, and have undergone characterization tests to determine their total acoustic power output, focusing range (in depth and laterally), focus quality, efficiency, and comparison tests to determine the material and technology of choice (PZT or piezocomposite) for intra-cavity HIFU applications. Array descriptions, characterization results, in-vitro and in-vivo results, and an overview of their intended use through the application software is shown.

  13. Factors influencing the ablative efficiency of high intensity focused ultrasound (HIFU) treatment for adenomyosis: A retrospective study.

    Science.gov (United States)

    Gong, Chunmei; Yang, Bin; Shi, Yarong; Liu, Zhongqiong; Wan, Lili; Zhang, Hong; Jiang, Denghua; Zhang, Lian

    2016-08-01

    Objectives The aim of this study was to investigate factors affecting ablative efficiency of high intensity focused ultrasound (HIFU) for adenomyosis. Materials and methods In all, 245 patients with adenomyosis who underwent ultrasound guided HIFU (USgHIFU) were retrospectively reviewed. All patients underwent dynamic contrast-enhanced magnetic resonance imaging (MRI) before and after HIFU treatment. The non-perfused volume (NPV) ratio, energy efficiency factor (EEF) and greyscale change were set as dependent variables, while the factors possibly affecting ablation efficiency were set as independent variables. These variables were used to build multiple regression models. Results A total of 245 patients with adenomyosis successfully completed HIFU treatment. Enhancement type on T1 weighted image (WI), abdominal wall thickness, volume of adenomyotic lesion, the number of hyperintense points, location of the uterus, and location of adenomyosis all had a linear relationship with the NPV ratio. Distance from skin to the adenomyotic lesion's ventral side, enhancement type on T1WI, volume of adenomyotic lesion, abdominal wall thickness, and signal intensity on T2WI all had a linear relationship with EEF. Location of the uterus and abdominal wall thickness also both had a linear relationship with greyscale change. Conclusion The enhancement type on T1WI, signal intensity on T2WI, volume of adenomyosis, location of the uterus and adenomyosis, number of hyperintense points, abdominal wall thickness, and distance from the skin to the adenomyotic lesion's ventral side can all be used as predictors of HIFU for adenomyosis. PMID:27385316

  14. 11C Choline PET Guided Salvage Radiotherapy with Volumetric Modulation Arc Therapy and Hypofractionation for Recurrent Prostate Cancer after HIFU Failure

    OpenAIRE

    Alongi, Filippo; Liardo, Rocco L. E.; Iftode, Cristina; Lopci, Egesta; Villa, Elisa; Comito, Tiziana; Tozzi, Angelo; Navarria, Pierina; Ascolese, Anna M.; Mancosu, Pietro; Tomatis, Stefano; Bellorofonte, Carlo; Arturo, Chiti; Scorsetti, Marta

    2014-01-01

    The purpose of this work was to evaluate tolerance, feasibility and acute toxicity in patients undergoing salvage radiotherapy after high-intensity focused ultrasound (HIFU) failure. From 2005 to 2011 a total of 15 patients were treated with HIFU as primary radical treatment. Between July 2011 and February 2013, all 15 patients presented biochemical relapse after HIFU and 11C choline PET documenting intrapostatic-only failure. Salvage EBRT was performed with moderate hypofractionation schedul...

  15. 一种色噪声下的自适应Kalman跟踪滤波器%An Adaptive Kalman Tracking Filter with Colored Noises

    Institute of Scientific and Technical Information of China (English)

    孙强; 惠晓滨; 黄鹤

    2011-01-01

    有色噪声干扰情况下非线性系统的状态估计是许多实际工程需要解决的问题.该文章针对传统Kalman滤波器噪声统计特性未知时,受色噪声的影响精度严重降低,甚至出现发散等现象,设计了一种基于神经模糊网络的自适应的Kalman滤波跟踪器.该滤波器通过利用神经模糊网络作为误差估计器,估计出Kalman滤波器的估计误差,从而对Kalman滤波跟踪器的预测结果进行修正,得到更优的预测值.计算机仿真结果表明,该算法可以克服传统算法的局限性,有效地防止滤波器发散,缩小实际的滤波误差,提高滤波精度,实现对跟踪结果的在线改进.%Estimation in nonlinear system with Colored Noises is problem in many projects. The traditional Kalman Filter is still deficient in tracking targets in the nonlinear systems with colored noises.An adaptive Kalman tracking algorithm based on neuro-fuzzy network is proposed in the paper. The estimation error is obtained online to modify the filtered result with neuro-fuzzy network as the estimator.The analysis of simulation results indicates preliminarily that our better tracking algorithm does restrain colored noise and improve that tracking accuracy. At same time it can reduce error of traditional algorithm and improve the tracking accuracy of the system online.

  16. Suppression Measured from Chinchilla Auditory-Nerve-Fiber Responses Following Noise-Induced Hearing Loss: Adaptive-Tracking and Systems-Identification Approaches.

    Science.gov (United States)

    Sayles, Mark; Walls, Michael K; Heinz, Michael G

    2016-01-01

    The compressive nonlinearity of cochlear signal transduction, reflecting outer-hair-cell function, manifests as suppressive spectral interactions; e.g., two-tone suppression. Moreover, for broadband sounds, there are multiple interactions between frequency components. These frequency-dependent nonlinearities are important for neural coding of complex sounds, such as speech. Acoustic-trauma-induced outer-hair-cell damage is associated with loss of nonlinearity, which auditory prostheses attempt to restore with, e.g., "multi-channel dynamic compression" algorithms.Neurophysiological data on suppression in hearing-impaired (HI) mammals are limited. We present data on firing-rate suppression measured in auditory-nerve-fiber responses in a chinchilla model of noise-induced hearing loss, and in normal-hearing (NH) controls at equal sensation level. Hearing-impaired (HI) animals had elevated single-fiber excitatory thresholds (by ~ 20-40 dB), broadened frequency tuning, and reduced-magnitude distortion-product otoacoustic emissions; consistent with mixed inner- and outer-hair-cell pathology. We characterized suppression using two approaches: adaptive tracking of two-tone-suppression threshold (62 NH, and 35 HI fibers), and Wiener-kernel analyses of responses to broadband noise (91 NH, and 148 HI fibers). Suppression-threshold tuning curves showed sensitive low-side suppression for NH and HI animals. High-side suppression thresholds were elevated in HI animals, to the same extent as excitatory thresholds. We factored second-order Wiener-kernels into excitatory and suppressive sub-kernels to quantify the relative strength of suppression. We found a small decrease in suppression in HI fibers, which correlated with broadened tuning. These data will help guide novel amplification strategies, particularly for complex listening situations (e.g., speech in noise), in which current hearing aids struggle to restore intelligibility. PMID:27080669

  17. Analytical approximations of the firing rate of an adaptive exponential integrate-and-fire neuron in the presence of synaptic noise

    Directory of Open Access Journals (Sweden)

    Loreen eHertäg

    2014-09-01

    Full Text Available Computational models offer a unique tool for understanding the network-dynamical mechanisms which mediate between physiological and biophysical properties, and behavioral function. A traditional challenge in computational neuroscience is, however, that simple neuronal models which can be studied analytically fail to reproduce the diversity of electrophysiological behaviors seen in real neurons, while detailed neuronal models which do reproduce such diversity are intractable analytically and computationally expensive. A number of intermediate models have been proposed whose aim is to capture the diversity of firing behaviors and spike times of real neurons while entailing a mathematical description as simple as possible. One such model is the exponential integrate-and-fire neuron with spike rate adaptation (aEIF which consists of two differential equations for the membrane potential (V and an adaptation current (w. Despite its simplicity, it can reproduce a wide variety of physiologically observed spiking patterns, can be fit to physiological recordings quantitatively, and, once done so, is able to predict spike times on traces not used for model fitting. Here we compute the steady-state firing rate of aEIF in the presence of Gaussian synaptic noise, using two approaches. The first approach is based on the 2-dimensional Fokker-Planck equation that describes the (V,w-probability distribution, which is solved using an expansion in the ratio between the time constants of the two variables. The second is based on the firing rate of the EIF model, which is averaged over the distribution of the $w$ variable. These analytically derived closed-form expressions were tested on simulations from a large variety of model cells quantitatively fitted to in vitro electrophysiological recordings from pyramidal cells and interneurons. Theoretical predictions closely agreed with the firing rate of the simulated cells fed with in-vivo-like synaptic noise.

  18. Seven-Year Outcomes Following HIFU in Patients with Localized Prostate Cancer

    Science.gov (United States)

    Uchida, Toyoaki; Shoji, Sunao; Nagata, Yoshihiro; Terachi, Toshiro; Illing, Rowland O.; Emberton, Mark

    2007-05-01

    We evaluated 409 patients suffering from localized prostate cancer treated with high-intensity focused ultrasound (HIFU). All patients were followed for at least 12 months after treatment. Biochemical failure was defined according to the criteria recommended by the American Society for Therapeutic Radiology and Oncology Consensus Panel. None of the patients received hormonal or other anticancer therapy before documentation of a biochemical failure. The biochemical disease-free rates at 5 years in patients with low, intermediate and high risk groups were 93%, 68% and 44%, respectively (pHIFU therapy appears to be a safe and efficacious minimally invasive therapy for patients with localized prostate cancer, especially those with a pretreatment PSA level less than 20 ng/ml or patients with low-risk group.

  19. Modelling of the acoustic field of a multi-element HIFU array scattered by human ribs.

    Science.gov (United States)

    Gélat, Pierre; Ter Haar, Gail; Saffari, Nader

    2011-09-01

    The efficacy of high-intensity focused ultrasound (HIFU) for the treatment of a range of different cancers, including those of the liver, prostate and breast, has been demonstrated. As a non-invasive focused therapy, HIFU offers considerable advantages over techniques such as chemotherapy and surgical resection in terms of reduced risk of harmful side effects. Despite this, there are a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the rib cage to induce tissue necrosis in the required volume whilst minimizing the formation of side lobes. Multi-element random-phased arrays are currently showing great promise in overcoming the limitations of single-element transducers. Nevertheless, successful treatment of a patient with liver tumours requires a thorough understanding of the way in which the ultrasonic pressure field from a HIFU array is scattered by the rib cage. In order to address this, a boundary element approach based on a generalized minimal residual (GMRES) implementation of the Burton-Miller formulation was used in conjunction with phase conjugation techniques to focus the field of a 256-element random HIFU array behind human ribs at locations requiring intercostal and transcostal treatment. Simulations were carried out on a 3D mesh of quadratic pressure patches generated using CT scan anatomical data for adult ribs 9-12 on the right side. The methodology was validated on spherical and cylindrical scatterers. Field calculations were also carried out for idealized ribs, consisting of arrays of strip-like scatterers, demonstrating effects of splitting at the focus. This method has the advantage of fully accounting for the effect of scattering and diffraction in 3D under continuous wave excitation.

  20. Cardiac Ventricular HIFU: Convergence of Experiment and Theory in the Canine Model

    Science.gov (United States)

    Muratore, Robert; Abe, Yukio; Homma, Shunichi; Bernardi, Richard; Kalisz, Andrew; Feleppa, Ernest J.

    2007-05-01

    OBJECTIVE: HIFU is a promising technique for treating cardiac ventricular diseases such as sustained ventricular tachycardia. Ablations can potentially destroy arrhythmogenic foci and block reentrant circuits. Towards this end, we have learned to control HIFU lesions in the canine model in vivo. METHODS: Experiment — Thoracotomies were performed on anesthetized dogs, following IACUC guidelines. In this open-chest configuration, a polyethylene water-filled bag was coupled to the myocardium with degassed ultrasound gel. The transducer was lowered into the water. Ventricular locations were targeted and insonified with multiple 200-ms HIFU bursts of 60-W acoustic power; the bursts were triggered with the electrocardiogram QRS complex. The therapeutic transducer was a 35-mm focal length, 33-mm diameter PZT annular array, excited at 5.25 MHz. Its -3dB focal region dimensions were 2.5 mm axially and 0.3 mm transversely. A confocal diagnostic transducer was used for aiming and for recording backscattered radiofrequency ultrasound data. Theory — A comprehensive acoustic model has been developed. Individual modules numerically simulate physical processes such as ultrasound beam propagation, energy transfer, and heat flow within tissue. One set of modules simulates HIFU ablation in moving tissue. Tissue motion was obtained from digitized B-mode videos of transverse cross sections of a beating canine heart. Epicardial and endocardial surface positions were extracted from the video frames. Additional simulations of static tissue compared linear and nonlinear propagation models. RESULTS: Significant agreement between simulated and measured lesion sizes and between linear and nonlinear propagation models was demonstrated.

  1. Modelling of the acoustic field of a multi-element HIFU array scattered by human ribs

    Science.gov (United States)

    Gélat, Pierre; ter Haar, Gail; Saffari, Nader

    2011-09-01

    The efficacy of high-intensity focused ultrasound (HIFU) for the treatment of a range of different cancers, including those of the liver, prostate and breast, has been demonstrated. As a non-invasive focused therapy, HIFU offers considerable advantages over techniques such as chemotherapy and surgical resection in terms of reduced risk of harmful side effects. Despite this, there are a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the rib cage to induce tissue necrosis in the required volume whilst minimizing the formation of side lobes. Multi-element random-phased arrays are currently showing great promise in overcoming the limitations of single-element transducers. Nevertheless, successful treatment of a patient with liver tumours requires a thorough understanding of the way in which the ultrasonic pressure field from a HIFU array is scattered by the rib cage. In order to address this, a boundary element approach based on a generalized minimal residual (GMRES) implementation of the Burton-Miller formulation was used in conjunction with phase conjugation techniques to focus the field of a 256-element random HIFU array behind human ribs at locations requiring intercostal and transcostal treatment. Simulations were carried out on a 3D mesh of quadratic pressure patches generated using CT scan anatomical data for adult ribs 9-12 on the right side. The methodology was validated on spherical and cylindrical scatterers. Field calculations were also carried out for idealized ribs, consisting of arrays of strip-like scatterers, demonstrating effects of splitting at the focus. This method has the advantage of fully accounting for the effect of scattering and diffraction in 3D under continuous wave excitation.

  2. HIFU scattering by the ribs: constrained optimisation with a complex surface impedance boundary condition

    Science.gov (United States)

    Gélat, P.; ter Haar, G.; Saffari, N.

    2014-04-01

    High intensity focused ultrasound (HIFU) enables highly localised, non-invasive tissue ablation and its efficacy has been demonstrated in the treatment of a range of cancers, including those of the kidney, prostate and breast. HIFU offers the ability to treat deep-seated tumours locally, and potentially bears fewer side effects than more established treatment modalities such as resection, chemotherapy and ionising radiation. There remains however a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the ribcage to ablate tissue at the required foci whilst minimising the formation of side lobes and sparing healthy tissue. Ribs both absorb and reflect ultrasound strongly. This sometimes results in overheating of bone and overlying tissue during treatment, leading to skin burns. Successful treatment of a patient with tumours in the upper abdomen therefore requires a thorough understanding of the way acoustic and thermal energy is deposited. Previously, a boundary element (BE) approach based on a Generalised Minimal Residual (GMRES) implementation of the Burton-Miller formulation was developed to predict the field of a multi-element HIFU array scattered by human ribs, the topology of which was obtained from CT scan data [1]. Dissipative mechanisms inside the propagating medium have since been implemented, together with a complex surface impedance condition at the surface of the ribs. A reformulation of the boundary element equations as a constrained optimisation problem was carried out to determine the complex surface velocities of a multi-element HIFU array which generated the acoustic pressure field that best fitted a required acoustic pressure distribution in a least-squares sense. This was done whilst ensuring that an acoustic dose rate parameter at the surface of the ribs was kept below a specified threshold. The methodology was tested at an

  3. EXPERIENCE WITH A HISTOSCANNING APPARATUS USED IN THE DIAGNOSIS OF RECURRENT PROSTATE CANCER AFTER HIFU ABLATION

    OpenAIRE

    P.V. Glybochko; Yu. G. Alyaev; A. V. Amosov; G. E. Krupinov; T. M. Ganzha; A. A. Obukhov; N. A. Amosov

    2012-01-01

    The new potentialities of 3D transrectal ultrasound study were realized in a HistoScanning diagnostic unit. It has been used at the R.M. Fronshtein Urology Clinic, Research Institute of Uronephrology and Reproductive Health, I.M. Sechenov First Moscow State Medical University, since September 2011. A study of the sensitivity and specificity of the technique enrolled patients undergoing high-intensity focused ultrasound (HIFU) ablation of the prostate of for its (PC) in the period 1 to 7 years...

  4. Prostate cancer multimodal therapy involvement in couple life: Open, Robotic and HIFU approach

    OpenAIRE

    Elisabeta Ioana Hirişcău; Doina Cosman; Ioan Coman

    2010-01-01

    The diagnosis and treatment of prostate cancer often results in significant physical side-effectsand associated psycho-social stressors that can interfere with the experience of sexual intimacy forcouples. Our study aims to evaluate couple’s sexual life and to determine any potential sexual dynamicdysfunctions which could occur before and after performing classic, robotic and HIFU radicalprostatectomy as a radical therapy in prostate cancer. The present article aims at the synopticpresentatio...

  5. Modelling of the acoustic field of a multi-element HIFU array scattered by human ribs

    Energy Technology Data Exchange (ETDEWEB)

    Gelat, Pierre [National Physical Laboratory, Hampton Road, Teddington TW11 0LW (United Kingdom); Ter Haar, Gail [Therapeutic Ultrasound Group, Physics Department, Institute of Cancer Research, Sutton SM2 5NG (United Kingdom); Saffari, Nader, E-mail: Pierre.Gelat@npl.co.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom)

    2011-09-07

    The efficacy of high-intensity focused ultrasound (HIFU) for the treatment of a range of different cancers, including those of the liver, prostate and breast, has been demonstrated. As a non-invasive focused therapy, HIFU offers considerable advantages over techniques such as chemotherapy and surgical resection in terms of reduced risk of harmful side effects. Despite this, there are a number of significant challenges which currently hinder its widespread clinical application. One of these challenges is the need to transmit sufficient energy through the rib cage to induce tissue necrosis in the required volume whilst minimizing the formation of side lobes. Multi-element random-phased arrays are currently showing great promise in overcoming the limitations of single-element transducers. Nevertheless, successful treatment of a patient with liver tumours requires a thorough understanding of the way in which the ultrasonic pressure field from a HIFU array is scattered by the rib cage. In order to address this, a boundary element approach based on a generalized minimal residual (GMRES) implementation of the Burton-Miller formulation was used in conjunction with phase conjugation techniques to focus the field of a 256-element random HIFU array behind human ribs at locations requiring intercostal and transcostal treatment. Simulations were carried out on a 3D mesh of quadratic pressure patches generated using CT scan anatomical data for adult ribs 9-12 on the right side. The methodology was validated on spherical and cylindrical scatterers. Field calculations were also carried out for idealized ribs, consisting of arrays of strip-like scatterers, demonstrating effects of splitting at the focus. This method has the advantage of fully accounting for the effect of scattering and diffraction in 3D under continuous wave excitation.

  6. Development and validation of a MRgHIFU non-invasive tissue acoustic property estimation technique.

    Science.gov (United States)

    Johnson, Sara L; Dillon, Christopher; Odéen, Henrik; Parker, Dennis; Christensen, Douglas; Payne, Allison

    2016-11-01

    MR-guided high-intensity focussed ultrasound (MRgHIFU) non-invasive ablative surgeries have advanced into clinical trials for treating many pathologies and cancers. A remaining challenge of these surgeries is accurately planning and monitoring tissue heating in the face of patient-specific and dynamic acoustic properties of tissues. Currently, non-invasive measurements of acoustic properties have not been implemented in MRgHIFU treatment planning and monitoring procedures. This methods-driven study presents a technique using MR temperature imaging (MRTI) during low-temperature HIFU sonications to non-invasively estimate sample-specific acoustic absorption and speed of sound values in tissue-mimicking phantoms. Using measured thermal properties, specific absorption rate (SAR) patterns are calculated from the MRTI data and compared to simulated SAR patterns iteratively generated via the Hybrid Angular Spectrum (HAS) method. Once the error between the simulated and measured patterns is minimised, the estimated acoustic property values are compared to the true phantom values obtained via an independent technique. The estimated values are then used to simulate temperature profiles in the phantoms, and compared to experimental temperature profiles. This study demonstrates that trends in acoustic absorption and speed of sound can be non-invasively estimated with average errors of 21% and 1%, respectively. Additionally, temperature predictions using the estimated properties on average match within 1.2 °C of the experimental peak temperature rises in the phantoms. The positive results achieved in tissue-mimicking phantoms presented in this study indicate that this technique may be extended to in vivo applications, improving HIFU sonication temperature rise predictions and treatment assessment. PMID:27441427

  7. MRI-Guided HIFU Methods for the Ablation of Liver and Renal Cancers.

    Science.gov (United States)

    de Senneville, Baudouin Denis; Moonen, Chrit; Ries, Mario

    2016-01-01

    MRI-guided High Intensity Focused Ultrasound (MRI-HIFU) is a promising method for the non-invasive ablation of pathological tissue in many organs, including mobile organs such as liver and kidney. The possibility to locally deposit thermal energy in a non-invasive way opens a path towards new therapeutic strategies with improved reliability and reduced associated trauma, leading to improved efficacy, reduced hospitalization and costs. Liver and kidney tumors represent a major health problem because not all patients are suitable for curative treatment with surgery. Currently, radio-frequency is the most used method for percutaneous ablation. The development of a completely non-invasive method based on MR guided high intensity focused ultrasound (HIFU) treatments is of particular interest due to the associated reduced burden for the patient, treatment related patient morbidity and complication rate. The objective of MR-guidance is hereby to control heat deposition with HIFU within the targeted pathological area, despite the physiological motion of these organs, in order to provide an effective treatment with a reduced duration and an increased level of patient safety. Regarding this, several technological challenges have to be addressed: Firstly, the anatomical location of both organs within the thoracic cage requires inter-costal ablation strategies, which preserve the therapeutic efficiency, but prevent undesired tissue damage to the ribs and the intercostal muscle. Secondly, both therapy guidance and energy deposition have to be rendered compatible with the continuous physiological motion of the abdomen. PMID:26486331

  8. Assessment of HIFU lesions by shear-wave elastography: Initial in-vivo results

    Science.gov (United States)

    Anquez, Jeremie; Corréas, Jean-Michel; Criton, Aline; Lacoste, François; Yon, Sylvain

    2012-11-01

    The aim of this work was to evaluate Shear Wave Elastography (SWE) as a tool to visualize HIFU lesions in an acute in-vivo setting. Extracorporeal HIFU sonications of liver were performed on 14 rabbits in 19 consecutive, adjacent pulses, with in situ energies between 75 J and 228 J. A set of images of the sonicated area was acquired prior and post HIFU ablation: 2 orthogonal SWE images (transverse and sagittal) and contrast enhanced CT scan. SWE images were acquired with theAixplorer® device (SuperSonic Imagine, Aix, France). Prior to the treatment, the liver elasticity appeared homogeneous, with a elasticity comprised between 5 and 11 kPa. The lesion extents were manually segmented on post-treatment SWE images and their areas A(SWE)T (transverse) and A(SWE)S (sagittal) were computed. On 3D CT the lesions were segmented as a hypo intense (devascularized) region on 3D CT images, and considered as "ground truth". The transverse and sagittal planes passing by their centers of mass were extracted. The lesion areas were computed for each plane, respectively A(CT)T and A(CT)S. The ratios A(CT)T/A(SWE)T and A(CT)S/A(SWE)S were computed for all the 14 cases. SWE appear to underestimate the lesion extent in the sagittal orientation with respect to CT images, while a good matching is obtained in the transverse orientation.

  9. High-Intensity Focused Ultrasound (HIFU) for the Treatment of Localized Prostate Cancer using Sonablate-500

    Science.gov (United States)

    Uchida, Toyoaki; Ohkusa, Hiroshi; Yamashita, Hideyuki; Nagata, Yoshihiro

    2005-03-01

    We evaluated 181 patients with localized prostate cancer treated with high-intensity focused ultrasound (HIFU) for biochemical disease-free rate, safety, morbidity and predictors of biochemical outcome. A total of 181 patients underwent HIFU with the Sonablate-500 and with at least 12 months of follow-up. Biochemical failure was defined according to the criteria recommended by the American Society for Therapeutic Radiology and Oncology Consensus Panel. The biochemical disease-free rates at 1, 3 and 5 years in all patients were 84%, 80% and 78%, respectively. The biochemical disease-free rates at 3 years for patients with pretreatment PSA less than 10 ng/ml, 10.01 to 20.0 ng/ml and more than 20.0 ng/ml were 94%, 75% and 35%, respectively (pHIFU therapy appears to be a safe and efficacious minimally invasive therapy for patients with localized prostate cancer, especially those with a pretreatment PSA level less than 20 ng/ml.

  10. Numerical study on the effective heating due to inertial cavitation in microbubble-enhanced HIFU therapy

    Science.gov (United States)

    Okita, Kohei; Sugiyama, Kazuyasu; Takagi, Shu; Matsumoto, Yoichiro

    2015-10-01

    The enhancement of heating due to inertial cavitation was focused in high-intensity focused ultrasound (HIFU) therapy. The influences of the rectified diffusion on microbubble-enhanced HIFU were examined numerically. A bubble dynamics equation in consideration of the spherical shell bubble and the elasticity of surrounding tissue was employed. Mass and heat transfer between the surrounding medium and the bubble were considered. The basic equations were discretized by finite difference method. The mixture phase and bubbles are coupled by the Euler-Lagrange method to take into account the interaction between ultrasound and bubbles. The mass transfer rate of gas from the surrounding medium to the bubble was examined as function of the initial bubble radius and the driving pressure amplitude. As the results, the pressure required to bubble growth was decreases with increasing the initial bubble radius. Thus, the injection of microbubble reduces the cavitation threshold pressure. On the other hand, the influence of the rectified diffusion on the triggered HIFU therapy which generates cavitation bubbles by high-intensity burst and induces the localized heating owing to cavitation bubble oscillation by low-intensity continuous waves. The calculation showed that the localized heating was enhanced by the increase of the equilibrium bubble size due to the rectified diffusion.

  11. 一台高强化柴油机排气噪声有源控制实验研究%Adaptive Active Exhaust Noise Control of a High Intensity Diese l Engine

    Institute of Scientific and Technical Information of China (English)

    李径定; 方卓毅; 罗永革

    2001-01-01

    Exhaust noise is the main noise source of a dieselengine,especially to a high intensity diesel engine.It worsen work environment of ope rators, and it may lead some disease in long time.An adaptive active noise control syste m is designed to control exhaust noise of a high intensity diesel engine,the experimental results manifest the system is very efficient in controlling the noise ,and it enhances the fuel economy.%柴油机噪声使操作人员工作环境恶化,长期还危害操作人员的身体健康。排气噪声对柴油机整机噪声贡献很大,本文设计了一套自适应有源噪声控制(AdaptiveActive Noise Control)系统用于控制排气噪声,实验结果表明该系统效果良好。

  12. 自适应滤波器消除语音信号中混合噪声%Elimination of Mixed-noise in Speech Singal by Adaptive Filter

    Institute of Scientific and Technical Information of China (English)

    高榕; 张仕凯; 李靖; 余昭杰; 丁传鹏; 李强

    2012-01-01

    The acquisition and transmission of speech signal are often mixed with a variety of noise or interference, such as sinusoidal narrow-band interference and Gaussian white noise. A simple adaptive filter is hard to filter out them simultaneously. In order to suppress mixed-noise to get a real voice signal,a two-stage adaptive filter program was proposed based on least mean square (LMS) adaptive algorithm and adaptive noise cancellation principle. By adding delay elements to a traditional adaptive noise cancellation, the first stage could eliminate the sinusoidal narrow-band interference, and the second stage was used to eliminate the Gaussian white noise. The two-stage adaptive filter was simulated by using Simulink block library. The simulation results show that the proposed filter can effectively filter out mixed-noise including sinusoidal narrow-band interference and Gaussian white noise,and improve the quality of speech signal.%语音信号在实际采集和传输的过程中,往往掺杂着多种噪声干扰,比较常见的是正弦窄带干扰和高斯白噪声,而一个简单的自适应滤波器往往很难同时滤除多种噪声.为了抑制混合噪声而得到真实的语音信号,在最小均方误差(LMS)自适应算法和自适应噪声抵消原理的基础上,提出了一种两级自适应滤波器方案,第1级在传统噪声抵消系统中加入延迟单元消除正弦窄带干扰,第Ⅱ级用LMS自适应噪声抵消器消除高斯白噪声,同时,利用Simulink模块库对所设计的两级自适应滤波器进行了建模仿真.仿真结果表明:该方案滤波器可以有效地滤除包含正弦窄带干扰和高斯白噪声的混合噪声,达到提高语音质量的目的.

  13. Using immunoadjuvant agent glycated chitosan to enhance anti-cancer stem like cell immunity induced by HIFU

    Science.gov (United States)

    Chen, Y.-L.; Chen, W.-R.; Liu, R.-S.; Yang, F.-Y.; Wang, C.-Y.; Lee, Y.-J.

    2013-02-01

    Thermal therapy is based on the observation that tumor cells are sensitive to increased temperature, which is important for tumor control. In this study, the high intensity focused ultrasound (HIFU) system was used to simulate thermal therapy on breast cancer control in the small animal model. Additionally, the immunoadjuvant agent, so called glycated chitosan (GC), was used to enhance the immunological effects on tumor control. The bioluminescent imaging showed that tumor metastasis was apparently suppressed by a combined treatment using HIFU and GC, but not in HIFU or GC alone. Using immunohistochemical (IHC) staining, lung metastasis of 4T1-3R tumor cells further agree the observations obtained from non-invasive in vivo imaging. We also found that plasma collected from mice treated with combined HIFU and GC could significantly suppress the viability of cultured 4T1 cells compared to untreated or single treated group. In summary, these results suggest that the HIFU therapy combined with GC can enhance the tumor immunogenicity and tumor control.

  14. Noise Pollution

    Science.gov (United States)

    ... Overview » Title IV - Noise Pollution Title IV - Noise Pollution The 1990 Clean Air Act Amendments added a ... abatement 7642 Authorization of appropriations What is Noise Pollution? The traditional definition of noise is “unwanted or ...

  15. Magnetic Resonance-Guided High-Intensity Focused Ultrasound (MR-HIFU) in Treatment of Symptomatic Uterine Myomas

    International Nuclear Information System (INIS)

    Magnetic Resonance-guided High-Intensity Focused Ultrasound (MR-HIFU) is a noninvasive technique for ablation therapy for uterine myomas, where focused ultrasound energy beam generates localized high temperature in the selected area and coagulates chosen tissue, leaving the skin and tissues in between unharmed. Magnetic resonance imaging enables accurate targeting for HIFU as well as temperature monitoring during treatment. MR guidance with 3D anatomical imaging provides reference data for treatment planning, while real-time temperature monitoring aids in controlling ablation process. This review provides basic information regarding methodology, clinical indications for this kind of treatment, expected outcome and patient management during MR-HIFU procedure. The aim of this work is to introduce a new, noninvasive treatment method for uterine leiomyomas and to present a comparison with other currently used methods

  16. High intensity focused ultrasound (HIFU) applied to hepato-bilio-pancreatic and the digestive system—current state of the art and future perspectives

    Science.gov (United States)

    Diana, Michele; Schiraldi, Luigi; Liu, Yu-Yin; Memeo, Riccardo; Mutter, Didier; Pessaux, Patrick

    2016-01-01

    Background High intensity focused ultrasound (HIFU) is emerging as a valid minimally-invasive image-guided treatment of malignancies. We aimed to review to current state of the art of HIFU therapy applied to the digestive system and discuss some promising avenues of the technology. Methods Pertinent studies were identified through PubMed and Embase search engines using the following keywords, combined in different ways: HIFU, esophagus, stomach, liver, pancreas, gallbladder, colon, rectum, and cancer. Experimental proof of the concept of endoluminal HIFU mucosa/submucosa ablation using a custom-made transducer has been obtained in vivo in the porcine model. Results Forty-four studies reported on the clinical use of HIFU to treat liver lesions, while 19 series were found on HIFU treatment of pancreatic cancers and four studies included patients suffering from both liver and pancreatic cancers, reporting on a total of 1,682 and 823 cases for liver and pancreas, respectively. Only very limited comparative prospective studies have been reported. Conclusions Digestive system clinical applications of HIFU are limited to pancreatic and liver cancer. It is safe and well tolerated. The exact place in the hepatocellular carcinoma (HCC) management algorithm remains to be defined. HIFU seems to add clear survival advantages over trans arterial chemo embolization (TACE) alone and similar results when compared to radio frequency (RF). For pancreatic cancer, HIFU achieves consistent cancer-related pain relief. Further research is warranted to improve targeting accuracy and efficacy monitoring. Furthermore, additional work is required to transfer this technology on appealing treatments such as endoscopic HIFU-based therapies. PMID:27500145

  17. Twelve years' experience with high-intensity focused ultrasound (HIFU) using sonablate™ devices for the treatment of localized prostate cancer

    Science.gov (United States)

    Uchida, Toyoaki; Nakano, Muyura; Shoji, Sunao; Nagata, Yoshihiro; Usui, Yukio; Terachi, Toshiro

    2012-10-01

    To report on the long-term results of high-intensity focused ultrasound (HIFU) in the treatment of localized prostate cancer. Patients with clinical Stage T1c-T3N0M0, biopsy proven, localized prostate cancer, with a serum prostate specific antigen (PSA) level of HIFU using the Sonablate™ (S) device and were required to have a minimal follow-up of 2 years after the last HIFU session to be included in this analysis. Four different generation HIFU devices, S200, S500, S500 version 4 and S500 TCM, have been used for this study. Biochemical failure was defined according to the Phoenix definition (PSA nadir+2ng/ml). Seven hundred and fifty-three men with prostate cancer were included. The patients were divided into two groups: in the Former group, 421 patients were treated with S200 and 500 from 1990 to 2005; in the Latter group, 332 patients were treated with S500 ver. 4 and TCM from 2005 to 2009. The mean age, PSA, Gleason score, operation time, and follow-up period in the Former and Latter groups were 68 and 67 years, 11.3 and 9.7 ng/ml, 6.2 and 6.6, 167 and 101 min, and 49 and 38 months, respectively. The biochemical disease-free rate (BDFR) in the groups at 5 years was, respectively, 67% and 53%, and was 50% at 10 years in the Former group (pprostate biopsy rate in the Former and Latter groups was 81% and 93%, respectively. Postoperative erectile dysfunction was noted in 45%, 38%, and 24% of patients at 6 months, 12 months, and 2 years after HIFU. The results after long-term follow-up have indicated that HIFU is an efficient and safe treatment for patients with localized prostate cancer, especially low-and intermediate-risk patients.

  18. The Feasibility of HIFU Liver Ablation Through the Ribcage and Cartilage in a Rodent Model

    Science.gov (United States)

    King, Randy; Rieke, Viola; Pauly, Kim Butts

    2009-04-01

    We examined the feasibility of the rat model for the study of HIFU treatment of liver cancer. Significance: HIFU is being developed for the minimally invasive treatment of primary and metastatic liver cancer. In patients, obstruction of the ultrasound by the ribs poses a significant problem, and current studies are under way which investigate the efficacy of focusing around or sonicating between the ribs. Such techniques show promise for patient treatments, but are not feasible when using rodent models. Results: Six recently euthanized (within the hour) Sprague-Dewey rats were used. The hair over the anterior surface was removed. Sonications were performed with the InSightec ExAblate system at 0.95 MHz, 1.1 MHz, and 1.35MHz through the rib cage. Temperature rise was monitored with MRI-based thermometry. Lesions were created in the livers of 5/6 rats. In the five rats, energy levels between 572-1194 Joules produced lesions every time. With energies greater than 1393 Joules, skin damaged was observed which prevented the ultrasound from propagating to the liver on subsequent sonications, accounting for the one study that failed to produce lesions. No thermal damage was observed at the skin with sonications that resulted in liver lesions, and no significant heating was observed at or near the skin in the MRI temperature maps. Conclusions: It is possible to ignore the effect of ribs and sternum in rodents and create lesions within the rat liver. This technique opens the door to using hepatocellular carcinoma rodent models in HIFU studies.

  19. High intensity focused ultrasound (HIFU) therapy for local treatment of hepatocellular carcinoma: Role of partial rib resection

    International Nuclear Information System (INIS)

    Objective: It has long been known that high intensity focused ultrasound (HIFU) can kill tissue through coagulative necrosis. However, it is only in recent years that practical clinical applications are becoming possible. Since the ribs have strong reflections to ultrasonic beams, they may affect the deposition of ultrasound energy, decreasing the efficacy of HIFU treatment and increasing the chance of adverse events when the intra-abdominal tumours concealed by ribs are treated. The aim of this study was to evaluate the influence of partial rib resection on the efficacy and safety of HIFU treatment. Methods: This prospective study was approved by the ethics committee at Chongqing University of Medical Sciences. An informed consent form was obtained from each patient and family member. A total of 16 patients with hepatocellular carcinoma (HCC), consisting of 13 males and 3 females, were studied. All patients had the successful HIFU treatment. To create a better acoustic pathway for HIFU treatment, all of the 16 patients had the ribs that shield the tumour mass to be removed. Magnetic resonance imaging (MRI) was used to evaluate the efficacy of HIFU treatment. Results: Sixteen cases had 23 nodules, including 12 cases with a single nodule, 1 case with 2 nodules, 3 cases with 3 nodules. The mean diameter of tumours was 7.0 ± 2.1 cm (5-10 cm). According to TNM classification, 9 patients were diagnosed as stage II, 4 patients were stage III, and 3 patients were stage IV. Follow-up imaging showed an absence of tumour blood supply and shrinkage of all treated lesions. The survival rates at 1, 2, 3, 4, and 5 years were 100%, 83.3%, 69.4%, 55.6%, and 55.6%, respectively. No serious complications were observed in the patients treated with HIFU. Conclusion: Partial rib resection can create a better acoustic pathway of HIFU therapy. Even though it is an invasive treatment, this measure offers patients an improved prospect of complete tumour ablation when no other treatment is

  20. Design and Simulation of Adaptive Active Noise Control System for Aircraft Helmet%飞行头盔主动噪声控制系统的设计及仿真研究

    Institute of Scientific and Technical Information of China (English)

    唐红; 王明皓; 吴凤霞

    2011-01-01

    Aiming at solving low frequency noise existing in cockpit,a design for adaptive active noise control system of aircraft helmet is proposed. Based on it,the filtered-XLMS algoritbm is simulated and analysed using MATLAB.The result shows that the effect of reducing aircraft noise on low frequency is very satisfactory with the scheme.%针对飞机驾驶舱内存在着大量的低频噪声,提出一种应用于飞行员头盔的自适应有源噪声控制系统设计方案,并在此基础上,利用MATLAB对FXLMS算法进行了仿真和性能分析。结果表明,此方案对飞机噪声低频段具有很好的降噪效果。

  1. First Experience Of Application Of High-Intensity Focused Ultrasonic Ablation (Hifu In Prostate Cancer Treatment

    Directory of Open Access Journals (Sweden)

    A.V. Stativko

    2009-12-01

    Full Text Available The scientific article points out that 40 sessions of HIFU prostate ablation have been performed for estimation of clinical efficiency. Average frequency of influences presents 628±164 impulses; average volume of tissues subjected to influence during one procedure is 33,8±16,3 smi (132 % of prostate volume; average operation time constitutes 150 minutes (from 90 to 200 minutes. During the operation no complications have been occurred. In the first days after the session of HIFU there was a peak of PSA increase and then during 1,5-3 months there was decrease to the lowest index. Minimal PSA level was reached in 10-12 weeks after treatment and it constituted from 0,04 till 1,1 ngml depending on the disease state. Reduction of prostate volume occurred in average from the 30th day of postoperative period and lasted for 6 months, reaching in average 50 % from initial volume. Postoperative period varied from 10 till 16 days and constituted in average 12±0,8 days. Thus application of high-intensity focused ultrasonic ablation allows treating successfully various stages of prostate cancer with minimal number of side-effects and makes possible the early estimation of treatment efficiency

  2. Multifunctional Bi2S3/PLGA nanocapsule for combined HIFU/radiation therapy.

    Science.gov (United States)

    Yao, Ming-hua; Ma, Ming; Chen, Yu; Jia, Xiao-qing; Xu, Guang; Xu, Hui-xiong; Chen, Hang-rong; Wu, Rong

    2014-09-01

    A multifunctional organic-inorganic hybrid nanocapsule based on Bi2S3-embedded poly (lactic-co-glycolic acid) (PLGA) nanocapsule has been elaborately designed to combine the merits of both polymeric shell structure and Bi2S3 nanoparticles. Hydrophobic Bi2S3 nanoparticles were successfully introduced into the PLGA nanocapsules via a facile and efficient water/oil/water (W/O/W) emulsion strategy. The elastic polymeric PLGA shell provides the excellent capability of ultrasound contrast imaging to the Bi2S3/PLGA. Meanwhile, the potential of these microcapsules to enhance the high intensity focused ultrasound (HIFU) therapy was demonstrated. Importantly, this research provided the first example of both in vitro and in vivo to demonstrate the radiosensitization effect of Bi2S3-embedded PLGA hybrid nanocapsules against prostate cancer under external X-ray irradiation. Thus, the successful integration of the Bi2S3 and PLGA nanocapsules provided an alternative strategy for the highly efficient ultrasound guided HIFU/RT synergistic therapy. PMID:24973300

  3. New Devices and Promising approaches for Clinical H.I.F.U. Applications

    Science.gov (United States)

    Tanter, Mickael; Aubry, Jean-François; Pernot, Mathieu; Marquet, Fabrice; Sinkus, Ralph; Fink, Mathias

    2007-05-01

    Bursts of focused ultrasound energy three orders of magnitude more intense than diagnostic ultrasound became during the last decade a noninvasive option for treating cancer from breast to prostate or uterin fibroid. However, many challenges remain to be addressed. First, the corrections of distortions induced on the ultrasonic therapy beam during its propagation through defocusing obstacles like skull bone or ribs remains today a technological performance that still needs to be validated clinically. Secondly, the problem of motion artifacts particularly important for the treatment of abdominal parts becomes today an important research topic. Finally, the problem of the treatment monitoring is a wide subject of interest in the growing HIFU community. For all these issues, the potential of new ultrasonic therapy devices able to work both in Transmit and Receive modes will be emphasized. A review of the work under achievement at L.O.A. using this new generation of HIFU prototypes on the monitoring, motion and aberrations corrections problems will be presented.

  4. 基于自适应开关插值算法的图像椒盐噪声滤波%Adaptive switching interpolation algorithm for filtering salt and pepper noise in image

    Institute of Scientific and Technical Information of China (English)

    苏锋; 朱旻芸; 杨秋菊

    2011-01-01

    针对传统中值滤波算法在滤除椒盐噪声时的缺点,提出了一种自适应开关插值算法.该方法根据椒盐噪声的特点,通过极大值、极小值和块均匀度检测来标志噪声,然后根据噪声分布情况,利用拉格朗日插值和自适应中值滤波来滤除噪声.实验结果表明,该方法对椒盐噪声密度为10%~80%的测试图像,能更加有效地抑制椒盐噪声并很好地保持了图像的细节信息,滤波性能比传统中值滤波方法更理想.该方法为图像去噪提供了一种新的途径.%According to shortcoming of conventional median filter algorithm in filtering salt and peper noise of image, the essay brought up a way of an adaptive switching interpolation filter. This method checked and identified noise through maximumminimum and block uniformity, and then according to the distributed noise, filtered noise by using Lagrange interpolation and adaptive median filter. Experiment results on images with noise densities from 10% to 80% show that the proposed filter performs well in reducing salt and pepper noise and maintains a good image detail information. Therefore it has better filtering performanee than the conventional median filter algorithm, and it provides a new way for image denoising.

  5. An Ultrasound Image-Based Dynamic Fusion Modeling Method for Predicting the Quantitative Impact of In Vivo Liver Motion on Intraoperative HIFU Therapies: Investigations in a Porcine Model.

    Directory of Open Access Journals (Sweden)

    W Apoutou N'Djin

    Full Text Available Organ motion is a key component in the treatment of abdominal tumors by High Intensity Focused Ultrasound (HIFU, since it may influence the safety, efficacy and treatment time. Here we report the development in a porcine model of an Ultrasound (US image-based dynamic fusion modeling method for predicting the effect of in vivo motion on intraoperative HIFU treatments performed in the liver in conjunction with surgery. A speckle tracking method was used on US images to quantify in vivo liver motions occurring intraoperatively during breathing and apnea. A fusion modeling of HIFU treatments was implemented by merging dynamic in vivo motion data in a numerical modeling of HIFU treatments. Two HIFU strategies were studied: a spherical focusing delivering 49 juxtapositions of 5-second HIFU exposures and a toroidal focusing using 1 single 40-second HIFU exposure. Liver motions during breathing were spatially homogenous and could be approximated to a rigid motion mainly encountered in the cranial-caudal direction (f = 0.20 Hz, magnitude > 13 mm. Elastic liver motions due to cardiovascular activity, although negligible, were detectable near millimeter-wide sus-hepatic veins (f = 0.96 Hz, magnitude 75%. Fusion modeling predictions were preliminarily validated in vivo and showed the potential of using a long-duration toroidal HIFU exposure to accelerate the ablation process during breathing (from 0.5 to 6 cm3 · min(-1. To improve HIFU treatment control, dynamic fusion modeling may be interesting for assessing numerically focusing strategies and motion compensation techniques in more realistic conditions.

  6. Compressed Sensing of Noisy Speech Signal Based on Adaptive Basis Pursuit De-noising%基于自适应基追踪去噪的含噪语音压缩感知

    Institute of Scientific and Technical Information of China (English)

    孙林慧; 杨震

    2011-01-01

    针对含白噪语音信号压缩采样后采用基追踪方法重构性能差的问题,提出了自适应基追踪去噪方法,该方法根据原含噪信号的信噪比自适应选择重构最佳参数,从而在重构语音的同时提高原信号信噪比.把该方法运用到含噪语音压缩感知中,对重构语音进行了主客观评价,并分析了不同压缩比下的重构性能.仿真结果显示:本文方法既实现了压缩采样,又在重构信号时实现了语音增强,优于基追踪重构方法%An adaptive basis pursuit de-noising method is proposed for compressed sensing of speech degraded by white Gaussian noise interference. This method adaptively selects the prime regularization parameter according to the SNR of original speech signal and enhancement is achieved as it is applied to noisy speech compression and reconstruction. The reconstructed speech signal via adaptive basis pursuit de-noising is evaluated by the objective and subjective evaluation. It is demonstrated that the performance of reconstructed speech based on adaptive basis pursuit de-noising is superior to basis pursuit,to low-SNR original speech signal.

  7. Respiratory-Gated MRgHIFU in Upper Abdomen Using an MR-Compatible In-Bore Digital Camera

    Directory of Open Access Journals (Sweden)

    Vincent Auboiroux

    2014-01-01

    Full Text Available Objective. To demonstrate the technical feasibility and the potential interest of using a digital optical camera inside the MR magnet bore for monitoring the breathing cycle and subsequently gating the PRFS MR thermometry, MR-ARFI measurement, and MRgHIFU sonication in the upper abdomen. Materials and Methods. A digital camera was reengineered to remove its magnetic parts and was further equipped with a 7 m long USB cable. The system was electromagnetically shielded and operated inside the bore of a closed 3T clinical scanner. Suitable triggers were generated based on real-time motion analysis of the images produced by the camera (resolution 640×480 pixels, 30 fps. Respiratory-gated MR-ARFI prepared MRgHIFU ablation was performed in the kidney and liver of two sheep in vivo, under general anaesthesia and ventilator-driven forced breathing. Results. The optical device demonstrated very good MR compatibility. The current setup permitted the acquisition of motion artefact-free and high resolution MR 2D ARFI and multiplanar interleaved PRFS thermometry (average SNR 30 in liver and 56 in kidney. Microscopic histology indicated precise focal lesions with sharply delineated margins following the respiratory-gated HIFU sonications. Conclusion. The proof-of-concept for respiratory motion management in MRgHIFU using an in-bore digital camera has been validated in vivo.

  8. Self-adaptive Filtering of Salt-pepper Noise in Images with Correlation Weights%基于相关权值的图像椒盐噪声自适应窗滤波

    Institute of Scientific and Technical Information of China (English)

    李天翼; 王明辉; 黄祖建; 朱斌

    2012-01-01

    A self-adaptive weighted mean algorithm is proposed for filtering the salt-pepper noise in images. The algorithm detects the noise pixel with minimum-maximum inspection, and then replaces the noise pixel with weighted mean value, where the weight of each pixel in neighborhood is set based on its correlation with the center pixel. The algorithm adapts itself to different noise densities by rec- tifying the filtering window according to the number of non-extremum pixels in neighborhood. Simulation results showed that, compared with other methods, the proposed algorithm achieves more satisfactory images while it gives better Signal-to-Noise Ratio (SNR) and Mean Squared Error( MSE), and exhibits more excellent in scenarios where the image is highly corrupted.%为有效滤除图像中椒盐噪声,提出一种基于相关权值的自适应窗滤波算法。算法基于极值检测判断噪声点并仅对噪声点滤波。引入灰度差刻画邻域像素与中心像素的相关性,以此为基础设置像素权值,对中心像素执行加权均值滤波。通过邻域窗口的自适应扩展适应噪声密度变化,并对邻域像素分区域设置权值,从而适应高椒盐噪声的滤除。仿真结果表明,本文算法能够有效滤除图像中的椒盐噪声,尤其在高椒盐噪声下性能表现更佳。

  9. FM Interference Noise Suppression Based on Adaptive Notch Filter%基于自适应陷波器的噪声调频干扰抑制方法

    Institute of Scientific and Technical Information of China (English)

    路翠华; 李国林; 谢鑫

    2014-01-01

    针对线性调频引信抗噪声干扰能力比较差的问题,提出了基于自适应陷波器的噪声调频干扰抑制方法。该方法根据线性调频引信差频信号的单频特性,将自适应陷波器应用到线性调频引信中,对噪声调频干扰进行抑制。通过自适应调整陷波器的权值,使陷波器在差频信号的频率点具有陷波特性,从而达到噪声调频干扰抑制的目的。仿真结果表明:SJB=-10 dB时,仍然能达到很好的噪声调频干扰抑制效果。%Aiming at the problem that linear frequency-modulated fuze’s ability of anti-noise interference was poor,the method of noise FM interference suppression based on adaptive notch filter was presented.According to the characteristic that the difference frequency signal of linear frequency-modulated fuze was monochromatic, an adaptive notch filter was adopted to suppress FM interference noise in linear frequency-modulated fuze. Through adj usting notch filter’s weights,the notch filter has the notch characteristics in difference frequency signal's frequency,then noise FM interference was suppressed.The simulation results showed that when SJR=-10dB,FM interference noise could be still suppressed effectively.

  10. Modeling pressure distribution and heat in the body tissue and extract the relationship between them in order to improve treatment planning in HIFU

    CERN Document Server

    Hajian, Saeed Reza; Pouladian, Majid; Hemmasi, Gholam Reza

    2016-01-01

    In high intensity focused ultrasound (HIFU) systems using non-ionizing methods in cancer treatment, if the device is applied to the body externally, the HIFU beam can damage nearby healthy tissues and burn skin due to lack of knowledge about the viscoelastic properties of patient tissue and failure to consider the physical properties of tissue in treatment planning. Addressing this problem by using various methods, such as MRI or ultrasound, elastography can effectively measure visco-elastic properties of tissue and fits within the pattern of stimulation and total treatment planning. In this paper, in a linear path of HIFU propagation, and by considering the smallest part of the path, including voxel with three mechanical elements of mass, spring and damper, which represents the properties of viscoelasticity of tissue, by creating waves of HIFU in the wire environment of MATLAB mechanics and stimulating these elements, pressure and heat transfer due to stimulation in the hypothetical voxel was obtained. Throu...

  11. High-Intensity Focused Ultrasound (HIFU) Using Sonablate® Devices for the Treatment of Benign Prostatic Hyperplasia and Localized Prostate Cancer: 18-year experience

    Science.gov (United States)

    Uchida, Toyoaki

    2011-09-01

    From 1993 to 2010, we have treated 156 patients benign prostatic hyperplasia (BPH) and 1,052 patients localized prostate cancer high-intensity focused ultrasound (HIFU). Four different HIFU devices, SonablateR-200, SonablateR-500, SonablateR-500 version 4 and Sonablate® TCM, have been used for this study. Clinical outcome of HIFU for BPH did not show any superior effects to transurethral resection of the prostate, laser surgery or transurethral vapolization of the prostate. However, HIFU appears to be a safe and minimally invasive therapy for patients with localized prostate cancer, especially low- and intermediate-risk patients. The rate of clinical outcome has significantly improved over the years due to technical improvements in the device.

  12. Snowmobile noise

    OpenAIRE

    Liikonen, Larri; Alanko, Mikko; Jokinen, Sirpa; Niskanen, Ilkka; Virrankoski, Lauri

    2007-01-01

    Planning snowmobiling routes and considering the possible need for off-road traffic restrictions requires that the noise impact of snowmobile traffic is known. The objective of this report was to take off-road readings in order to determine snowmobile noise emissions and the spread of noise from snowmobile routes into the environment. Based on the readings taken, it can be said that the noise zones created by snowmobile traffic are quite narrow at current traffic levels. Noise pollution ca...

  13. Industrial Noise

    OpenAIRE

    Mehran zolfaghari

    1996-01-01

    Various risk factors in industrial environments can affect hearing status and healthy in today’s modern society. Noise control and hearing conservation program is very crucial in preventing workers exposed to high levels of noise in the work places. In the current article we are going to discuss issues such as industrial noise control, noise characteristics and standards and techniques for noise control. Then the methods for individual hearing conservation and medical care will be described i...

  14. Predicting and Preventing Skull Overheating in Non Invasive Brain HIFU Treatment Protocols

    International Nuclear Information System (INIS)

    Ultrasound brain therapy is currently limited by the strong phase and amplitude aberrations induced by the heterogeneities of the skull. However the development of aberration correction techniques has made it possible to correct the beam distortion induced by the skull and to produce a sharp focus in the brain. Moreover, using the density of the skull bone that can be obtained with high-resolution CT scans, the corrections needed to produce this sharp focus can be calculated using ultrasound propagation models. We propose here a model for computing the temperature elevation in the skull during High Intensity Focused Ultrasound (HIFU) transcranial therapy. Based on CT scans, the wave propagation through the skull is computed with 3D finite differences wave propagation software. The acoustic simulation is combined with a 3D thermal diffusion code and the temperature elevation inside the skull is computed. Finally, the simulation is validated experimentally by measuring the temperature elevation in several locations of the skull

  15. Interference-free ultrasound imaging during HIFU therapy, using software tools

    Science.gov (United States)

    Vaezy, Shahram (Inventor); Held, Robert (Inventor); Sikdar, Siddhartha (Inventor); Managuli, Ravi (Inventor); Zderic, Vesna (Inventor)

    2010-01-01

    Disclosed herein is a method for obtaining a composite interference-free ultrasound image when non-imaging ultrasound waves would otherwise interfere with ultrasound imaging. A conventional ultrasound imaging system is used to collect frames of ultrasound image data in the presence of non-imaging ultrasound waves, such as high-intensity focused ultrasound (HIFU). The frames are directed to a processor that analyzes the frames to identify portions of the frame that are interference-free. Interference-free portions of a plurality of different ultrasound image frames are combined to generate a single composite interference-free ultrasound image that is displayed to a user. In this approach, a frequency of the non-imaging ultrasound waves is offset relative to a frequency of the ultrasound imaging waves, such that the interference introduced by the non-imaging ultrasound waves appears in a different portion of the frames.

  16. Real-Time Tissue Change Monitoring on the Sonablate® 500 during High Intensity Focused Ultrasound (HIFU) Treatment of Prostate Cancer

    Science.gov (United States)

    Chen, Wo-Hsing; Sanghvi, Narendra T.; Carlson, Roy; Uchida, Toyoaki

    2011-09-01

    Sonablate® 500 (SB-500) HIFU devices have been successfully used to treat prostate cancer non-invasively. In addition, Visually Directed HIFU with the SB-500 has demonstrated higher efficacy. Visually Directed HIFU works by displaying hyperechoic changes on the B-mode ultrasound images. However, small changes in the grey-scale images are not detectable by Visually Directed HIFU. To detect all tissue changes reliably, the SB-500 was enhanced with quantitative, real-time Tissue Change Monitoring (TCM) software. TCM uses pulse-echo ultrasound backscattered RF signals in 2D to estimate changes in the tissue properties caused by HIFU. The RF signal energy difference is calculated in selected frequency bands (pre and post HIFU) for each treatment site. The results are overlaid on the real-time ultrasound image in green, yellow and orange to represent low, medium and high degree of change in backscattered energy levels. The color mapping scheme was derived on measured temperature and backscattered RF signals from in vitro chicken tissue experiments. The TCM software was installed and tested in a clinical device to obtain human RF data. Post HIFU contrast enhanced MRI scans verified necrotic regions of the prostate. The color mapping success rate at higher HIFU power levels was 94% in the initial clinical test. Based on these results, TCM software has been released for wider usage. The clinical studies with TCM in Japan and The Bahamas have provided the following PSA (ng/ml) results. Japan (n = 97), PSA pre-treatment/post-treatment; minimum 0.7/0.0, maximum 76.0/4.73, median 6.89/0.07, standard deviation 11.19/0.62. The Bahamas (n = 59), minimum 0.4/0.0, maximum 13.0/1.4, median 4.7/0.1, standard deviation 2.8/0.3.

  17. Transrectal high-intensity focused ultrasound (HIFU) treatment of localized prostate cancer: Review of technical incidents and morbidity after 5 years of use

    OpenAIRE

    RIPERT, Thomas; AZEMAR, Marie Dominique; MENARD, Johann; BAYOUD, Younes; Messaoudi, Rabah; Duval, François; Staerman, Frédéric

    2010-01-01

    Abstract OBJECTIVE To report on technical incidents, and early and late complications, occurring on high-intensity focused ultrasound (HIFU) treatment of patients with localized prostate cancer. PATIENTS AND METHODS We performed a retrospective review of patients who were treated by Ablatherm? in our centre. We recorded all technical incidents, treatment discontinuations, and early (< 1 month) and late complications. RESULTS A total of 74 HIFU procedures were perfor...

  18. Prognostic factors in the estimation of HIFU treatment efficiency in patients with localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Popkov V.M.

    2013-03-01

    Full Text Available Research objective: To study the role of prognostic factors in the estimation of risk development of recurrent prostate cancer after treatment by high-intensive focused ultrasound (HIUF. Objects and Research Methods: The research has included 102 patients with morphologically revealed localized prostate cancer by biopsy. They have been on treatment in Clinic of Urology of the Saratov Clinical Hospital n.a. S. R. Mirotvortsev. 102 sessions of initial operative treatment of prostate cancer by the method of HIFU have been performed. The general group of patients (n=102 has been subdivided by the method of casual distribution into two samples: group of patients with absent recurrent tumor and group of patients with the revealed recurrent tumor, by morphological research of biopsy material of residual prostate tissue after HIFU. The computer program has been used to study the signs of outcome of patients with prostate cancer. Results: Risk of development of recurrent prostate cancer has grown with the PSA level raise and its density. The index of positive biopsy columns <0,2 has shown the recurrence of prostate cancer in 17% cases while occurrence of prostate cancer in 59% cases has been determined by the index of 0,5 and higher. The tendency to obvious growth of number of relapses has been revealed by the sum of Glison raise with present perineural invasion. Cases of recurrent prostate cancer have been predominant in patients with lymphovascular invasions. In conclusion it has been worked out that the main signs of recurrent prostate cancer development may include: PSA, PSA density, the sum of Glison, lymphovascular invasion, invasion.

  19. 基于互补自适应噪声的集合经验模式分解算法%Ensemble Empirical Mode Decomposition Base on Complementary Adaptive Noises

    Institute of Scientific and Technical Information of China (English)

    蔡念; 黄威威; 谢伟; 叶倩; 杨志景

    2015-01-01

    Empirical Model Decomposition (EMD) and its improved algorithms are most useful signal processing methods. However, those methods still lack rigorous mathematical theory. This paper attempts to analyze mathematically the reconstruction errors for Ensemble EMD (EEMD) and EEMD with Adaptive Noises (EEMDAN). Moreover, the formulae of the residual noise are deduced step by step. There exists the residual noise in each intrinsic mode function during the EEMDAN. To suppress the residual noise, an improved ensemble empirical mode decomposition with complementary adaptive noises by adding pairs of positive and negative noises is proposed. The experimental results indicate that the proposed method can obviously reduce the residual noise in each intrinsic mode function compared with the EEMD and the EEMDAN, and it also has better signal reconstruction precision and faster signal decomposition.%经验模式分解(EMD)及其改进算法作为实用的信号处理方法至今仍然缺少严格的数学理论。该文尝试从数学理论上分析集合经验模式分解和自适应噪声集合经验模式分解的重构误差,推导了总体残留噪声的计算公式。针对自适应噪声集合经验模式分解在每一层固有模态分量上仍然存在残留噪声的问题,在分解过程中添加成对的正负噪声分量,提出一种基于互补自适应噪声的集合经验模式分解算法。实验结果表明,相比于集合经验模式分解和自适应噪声集合经验模式分解,所提的方法能够明显地减少每一层固有模态分量中残留的噪声,拥有较好的信号重构精度和更快的分解速度。

  20. 多通道自适应主动噪声控制系统设计及实验%Design and Experiment of Multi-Channel Adaptive Active Noise Control System

    Institute of Scientific and Technical Information of China (English)

    王春云; 吴亚锋; 杨浩; 储妮晟

    2011-01-01

    设计了一种多路自适应主动噪声控制系统,该系统具有4路误差输入和2路抵消输出,详细介绍了系统的设计方法、结构组成和控制原理.利用该系统,在一个普通封闭房间分别完成了对160 Hz单频正弦噪声,三阶谐频噪声和实际录取的某型号潜艇噪声进行了控制实验,分别取得了20 dB、10 dB和8 dB的降噪效果,验证了该系统的可行性和有效性.%A multi-channel self-adaptive active noise control system is designed. It has four error inputs and two offset outputs. Furthermore, the structure, design method and control principle are introduced in detail. Using this system, 160 Hz single-frequency sine noise, the third order harmonic sinusoidal noise and the actual noise from a certain type of submarine are experimented respectively in an ordinary closed room and the effect of 8 dB, 10 dB and 20 dB are obtained respectively. The experimental result verifies the feasibility and effectiveness of the system.

  1. An Adaptive De-Noising Method for Vehicle's Acceleration Signal Based on PDE%一种基于偏微分方程的车辆加速度信号自适应降噪方法

    Institute of Scientific and Technical Information of China (English)

    徐叶雷; 黄青华; 方勇

    2009-01-01

    提出一种针对MEMS加速度计信号的基于偏微分方程的自适应降噪方法,该方法不仅能有效克服由于传感器本身原因及车载环境振动噪声带来的影响,获得准确的加速度信号,而且实现容易、实时性好.通过对车辆加速度信号进行建模并叠加真实加速度噪声作为仿真信号,将该方法与选用db6小波基、heursure自适应阈值、4层分解的最佳小波进行降噪性能对比,证明在车辆正常行驶的加速度幅值下,该方法不仅能够取得和小波近似的降噪性能,而且很大程度上减少了运算时间.最后通过对实际车载加速度信号的降噪处理和倾角测量中的应用,再次证明该方法在滤除噪声的同时能够较好体现细节信息,很适合应用在对实时性和准确性要求高的实际工程中.%An adaptive de-noising method was put forward for MEMS accelerometer signal based on partial differential equation. This method can reduce the disturbance caused by vibration of vehicular environment and sensor itself, get acceleration accurately,and have advantages of easy realization and good real-time performance. A vehicle's acceleration signal modeling was set up with real acceleration noises as simulation signals. Compared to the best wavelet in such signal with characters of db6 wavelet base,heursure adaptive threshold, and four decomposed layers, the adaptive de-noising method could perform quite same as wavelet in de-noising,but largely reduce the computation time. Experiments proved above result,while the car was in normal driving conditions. And experiments based on real vehicle acceleration signal and angle measurement proved again that this method could reflect the detailed information effectively while filtering noise, and it was very suitable for practical engineering which needs real-time applications and high accuracy.

  2. 环境噪音对鸟类鸣声的影响及鸟类的适应对策%Impacts of ambient noise on bird song and adaptation strategies of birds

    Institute of Scientific and Technical Information of China (English)

    季婷; 张雁云

    2011-01-01

    For the animals living in the areas with high level ambient noise, their call signals could be overlapped with the frequency, amplitude , and temporal characters of the noise , making the spread efficiency of the animals acoustic signals decreased. Birds mainly rely on their songs for communication. The lower level spread efficiency of their acoustic signal will impact their individual recognition, mate selection, territorial defense, population density, community structure, and so on. This paper summarized the impacts of ambient noise, including urban noise and natural noise, on bird song and the adaptation strategies of birds, pointed out the concerns of these impacts in urbanization, and prospected the possible hotspots in the future research.%在高噪音环境中生存的动物,发出的声信号会与噪声的频率、振幅和时间等重叠,使动物声信号的传播效率降低.鸟类主要靠鸣声通讯,鸣声传播效率下降会影响鸟类个体间识别、配偶关系、领域防卫、种群密度、群落结构等.本文综述了城市噪音、自然噪音等环境噪声对鸟类鸣声的影响以及鸟类的适应对策,提出在城市化进程中要关注噪音对鸟类的影响,并展望了本领域今后可能的研究热点.

  3. Experimental Validation of a Novel MRI-Compatible HIFU Device for the Treatment of Superficial Venous Insufficiency

    Science.gov (United States)

    Salomir, Rares; Pichardo, Samuel; Petrusca, Lorena; Angel, Yves; Lacoste, François; Chapelon, Jean-Yves

    2007-05-01

    A novel High Intensity Focused Ultrasound (HIFU) probe has been designed for minimally-invasive treatment of valvular dysfunction in the saphenous vein, which is known to be the cause of superficial venous insufficiency (SVI) and varicose veins. Treating SVI with HIFU is possible, since venous tissue undergoes localized partial shrinkage when subjected to high temperature elevation. In a previous study in vitro we demonstrated that diameter shrinkage should be sufficient to restore valvular function, as this is done in the more aggressive approach known as external valvuloplasty. Numerical optimization using fast simulations of pressure field have led to a non-spherically shaped probe design with two HIFU elements that focus ultrasound uniformly over a line of length 7 mm, at a depth of 15 mm from the skin. A MR-compatible prototype of the probe has been constructed and this was characterized 1). by electroacustical mapping of the pressure field in water, and 2). by fast, high resolution MR thermal mapping ex vivo on fresh meat samples. Results were in good agreement with those predicted by an analytical approach and numerical simulations. Available experimental data suggest that a short sonication (less than 10 sec duration) should permit sufficient temperature elevation to obtain vein shrinkage. Further studies will be performed on surgically excised samples of human veins under MR thermal mapping in order to determine the optimal sonication parameters (duration and power level).

  4. High-Intensity Focused Ultrasound (HIFU) Using Sonablate-500 for the Treatment of Localized Prostate Cancer: 6-year experience

    Science.gov (United States)

    Uchida, Toyoaki; Shoji, Sunao; Nagata, Yoshihiro

    2006-05-01

    We evaluated 281 patients of localized prostate cancer treated with high-intensity focused ultrasound (HIFU) for biochemical disease-free rate, safety, morbidity and predictors of biochemical outcome. A total of 281 patients underwent HIFU with the use of Sonablate-500 and with at least 12 months of follow-up. Biochemical failure was defined according to the criteria recommended by the American Society for Therapeutic Radiology and Oncology Consensus Panel. The biochemical disease-free rates at 1, 3 and 5 years in all patients were 78%, 74% and 72%, respectively. The biochemical disease-free rates at 5 years for patients with pretreatment PSA less than 10 ng/ml, 10.01 to 20.0 ng/ml and more than 20.0 ng/ml were 88%, 70% and 17%, respectively (pHIFU therapy appears to be a safe and efficacious minimally invasive therapy for patients with localized prostate cancer, especially those with a pretreatment PSA level less than 20 ng/ml.

  5. Unjust noise

    OpenAIRE

    Paul Voice

    2009-01-01

    In this paper I argue that noise is a significant source of social harm and thoseharmed by noise often suffer not merely a misfortune but an injustice. I arguethat noise is a problem of justice in two ways; firstly, noise is a burden of socialcooperation and so the question of the distribution of this burden arises. And,secondly, some noises, although burdensome, are nevertheless just becausethey arise from practices that are ‘reasonable’. I offer a number of distinctions,between necessary an...

  6. M-HIFU inhibits tumor growth, suppresses STAT3 activity and enhances tumor specific immunity in a transplant tumor model of prostate cancer.

    Directory of Open Access Journals (Sweden)

    Xiaoyi Huang

    Full Text Available OBJECTIVE: In this study, we explored the use of mechanical high intensity focused ultrasound (M-HIFU as a neo-adjuvant therapy prior to surgical resection of the primary tumor. We also investigated the role of signal transducer and activator of transcription 3 (STAT3 in M-HIFU elicited anti-tumor immune response using a transplant tumor model of prostate cancer. METHODS: RM-9, a mouse prostate cancer cell line with constitutively activated STAT3, was inoculated subcutaneously in C57BL/6J mice. The tumor-bearing mice (with a maximum tumor diameter of 5∼6 mm were treated by M-HIFU or sham exposure two days before surgical resection of the primary tumor. Following recovery, if no tumor recurrence was observed in 30 days, tumor rechallenge was performed. The growth of the rechallenged tumor, survival rate and anti-tumor immune response of the animal were evaluated. RESULTS: No tumor recurrence and distant metastasis were observed in both treatment groups employing M-HIFU + surgery and surgery alone. However, compared to surgery alone, M-HIFU combined with surgery were found to significantly inhibit the growth of rechallenged tumors, down-regulate intra-tumoral STAT3 activities, increase cytotoxic T cells in spleens and tumor draining lymph nodes (TDLNs, and improve the host survival. Furthermore, M-HIFU combined with surgery was found to significantly decrease the level of immunosuppression with concomitantly increased number and activities of dendritic cells, compared to surgery alone. CONCLUSION: Our results demonstrate that M-HIFU can inhibit STAT3 activities, and when combined synergistically with surgery, may provide a novel and promising strategy for the treatment of prostate cancers.

  7. Development of Active Noise Control System for Quieting Transformer Noise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

  8. Prostate cancer multimodal therapy involvement in couple life: Open, Robotic and HIFU approach

    Directory of Open Access Journals (Sweden)

    Elisabeta Ioana Hirişcău

    2010-12-01

    Full Text Available The diagnosis and treatment of prostate cancer often results in significant physical side-effectsand associated psycho-social stressors that can interfere with the experience of sexual intimacy forcouples. Our study aims to evaluate couple’s sexual life and to determine any potential sexual dynamicdysfunctions which could occur before and after performing classic, robotic and HIFU radicalprostatectomy as a radical therapy in prostate cancer. The present article aims at the synopticpresentation of results of a statistic research done by the author regarding the factors that influencecouple’s sex life, and also at the identification of potential dynamic disorder that could come up before aradical prostatectomy (disorders that influence the sexual prognostic following the intervention. Materialand method: the research involved 28 couples (56 individuals and was conducted in The Municipal Clinicand in The Endoplus Clinic in Cluj-Napoca. The initial evaluation aimed to identify sexual dynamicdysfunctions before the intervention. The couples filled in an interview sheet before the intervention andwere informed about the immediate and long term effects of the intervention and of existing therapeuticsolutions. The confidentiality of interview answers has been insured and the interviews have beencollected and sealed the day of the intervention. The structure of the interview is based on the BASIC IDgrid proposed by Lazarus in 1973 which aims to establish a therapeutic action profile which would allow amultimodal intervention. All patients underwent the prostate cancer intervention as follows: 10 patientsunderwent open surgery, 9 patients robotic surgery and 9 patients HIFU therapy. Results: Each partnerof the couple was reevaluated two months after the radical therapy. The main goal of evaluating thesexual behavior was to obtain valid information in order to make the optimal therapeutic decision. Thepartner’s answer frequency for both pre and

  9. A framework for the correction of slow physiological drifts during MR-guided HIFU therapies: Proof of concept

    Energy Technology Data Exchange (ETDEWEB)

    Zachiu, Cornel, E-mail: C.Zachiu@umcutrecht.nl; Moonen, Chrit; Ries, Mario [Imaging Division, UMC Utrecht, Heidelberglaan 100, Utrecht 3584 CX (Netherlands); Denis de Senneville, Baudouin [Imaging Division, UMC Utrecht, Heidelberglaan 100, Utrecht 3584 CX (Netherlands); Mathematical Institute of Bordeaux, University of Bordeaux, Talence Cedex 33405 (France)

    2015-07-15

    Purpose: While respiratory motion compensation for magnetic resonance (MR)-guided high intensity focused ultrasound (HIFU) interventions has been extensively studied, the influence of slow physiological motion due to, for example, peristaltic activity, has so far been largely neglected. During lengthy interventions, the magnitude of the latter can exceed acceptable therapeutic margins. The goal of the present study is to exploit the episodic workflow of these therapies to implement a motion correction strategy for slow varying drifts of the target area and organs at risk over the entire duration of the intervention. Methods: The therapeutic workflow of a MR-guided HIFU intervention is in practice often episodic: Bursts of energy delivery are interleaved with periods of inactivity, allowing the effects of the beam on healthy tissues to recede and/or during which the plan of the intervention is reoptimized. These periods usually last for at least several minutes. It is at this time scale that organ drifts due to slow physiological motion become significant. In order to capture these drifts, the authors propose the integration of 3D MR scans in the therapy workflow during the inactivity intervals. Displacements were estimated using an optical flow algorithm applied on the 3D acquired images. A preliminary study was conducted on ten healthy volunteers. For each volunteer, 3D MR images of the abdomen were acquired at regular intervals of 10 min over a total duration of 80 min. Motion analysis was restricted to the liver and kidneys. For validating the compatibility of the proposed motion correction strategy with the workflow of a MR-guided HIFU therapy, an in vivo experiment on a porcine liver was conducted. A volumetric HIFU ablation was completed over a time span of 2 h. A 3D image was acquired before the first sonication, as well as after each sonication. Results: Following the volunteer study, drifts larger than 8 mm for the liver and 5 mm for the kidneys prove that

  10. 一种基于自适应滤波器的潜艇辐射噪声仿真方法%A Simulation Method for Submarine Radiation Noise Based on Adaptive Filter

    Institute of Scientific and Technical Information of China (English)

    孙时珍

    2013-01-01

      文章提出了一种基于自适应滤波器的潜艇辐射噪声仿真方法。在对潜艇辐射噪声连续谱、线谱和调制谱的数学模型进行研究的基础上,利用Ecs型功率谱模型,基于自适应滤波器,通过傅里叶反变换对潜艇辐射噪声连续谱进行了仿真,分别叠加了线谱信号和调制谱信号之后,得到潜艇辐射噪声的仿真结果。通过对仿真结果的分析和利用仿真结果与实装进行对接测试,表明仿真的辐射噪声逼真度较高。%A simulation method for submarine radiation noise based on adaptive filter was proposed. Based on the research on the mathematical models of continuous spectrum, line spectrum and modulation spectrum of sub⁃marine radiation noise, the continuous spectrum of submarine radiation noise was simulated via inverse fourier transform based on adaptive filter using Ecs spectrum model. The simulation results was obtained after superpose⁃ing the line sepctrum signal and modulation signal. The analysis and equipment test of the simulation results showed that its naturalness was so good that the method was practical.

  11. The safety and feasibility of extracorporeal high-intensity focused ultrasound (HIFU) for the treatment of liver and kidney tumours in a Western population.

    Science.gov (United States)

    Illing, R O; Kennedy, J E; Wu, F; ter Haar, G R; Protheroe, A S; Friend, P J; Gleeson, F V; Cranston, D W; Phillips, R R; Middleton, M R

    2005-10-17

    High-intensity focused ultrasound (HIFU) provides a potential noninvasive alternative to conventional therapies. We report our preliminary experience from clinical trials designed to evaluate the safety and feasibility of a novel, extracorporeal HIFU device for the treatment of liver and kidney tumours in a Western population. The extracorporeal, ultrasound-guided Model-JC Tumor Therapy System (HAIFU Technology Company, China) has been used to treat 30 patients according to four trial protocols. Patients with hepatic or renal tumours underwent a single therapeutic HIFU session under general anaesthesia. Magnetic resonance imaging 12 days after treatment provided assessment of response. The patients were subdivided into those followed up with further imaging alone or those undergoing surgical resection of their tumours, which enabled both radiological and histological assessment. HIFU exposure resulted in discrete zones of ablation in 25 of 27 evaluable patients (93%). Ablation of liver tumours was achieved more consistently than for kidney tumours (100 vs 67%, assessed radiologically). The adverse event profile was favourable when compared to more invasive techniques. HIFU treatment of liver and kidney tumours in a Western population is both safe and feasible. These findings have significant implications for future noninvasive image-guided tumour ablation. PMID:16189519

  12. Validation of tissue change monitoring (TCM) on the Sonablate® 500 during high intensity focused ultrasound (HIFU) treatment of prostate cancer with real-time thermometry

    Science.gov (United States)

    Chen, Wo-Hsing; Sanghvi, Narendra T.; Carlson, Roy; Schatzl, Georg; Marberger, Michael

    2012-10-01

    The Sonablate® 500 has quantitative, real-time Tissue Change Monitoring (TCM) software that estimates changes in tissue properties due to HIFU treatment of prostate cancer. This study validates the Sonablate 500 TCM system using real-time thermometry. Five patients with histologically confirmed, organ-confined prostate cancer were enrolled. Four patients with focal cancer had hemiablation and one had whole gland ablation. TCM generates energy reading based on spectral analysis on the RF backscattered ultrasound signals; results are used as an estimator of tissue temperature. Needle thermocouples were placed transperineally under TRUS guidance in the prostate to monitor temperatures from focal zone, posterior to the focal zone and on the lateral gland where no HIFU was applied. The HIFU treatments averaged 37, 35 and 19.7 Watts for the treatment for anterior, middle and posterior zones. The measured temperatures (Average, Max, and Min) in the HIFU treatment zones were 84, 114 and 70 degrees C. The temperature estimated by TCM energy readings were 83% 75-100 degrees C and 17% 60-75 degrees C with an average of 91 degrees C. Outside the focal zone, average recorded temperature was 50 degrees C. Average temperature in the lateral lobe where no HIFU was applied was 40.7 degrees C.

  13. Increasing the HIFU ablation rate through an MRI-guided sonication strategy using shock waves: feasibility in the in vivo porcine liver.

    Science.gov (United States)

    Ramaekers, P; de Greef, M; van Breugel, J M M; Moonen, C T W; Ries, M

    2016-02-01

    This study investigated whether an MR-guided pulsed HIFU ablation strategy could be implemented under clinical conditions, using a transducer designed for uterine fibroid ablation, to obtain an ablation rate that is sufficiently high for clinical abdominal HIFU therapy in highly perfused organs. A pulsed HIFU ablation strategy, aimed at increasing the energy absorption in the HIFU focal area by local shock wave formation in the non-linear pressure regime, was compared to an energy-equivalent continuous wave sonication strategy in the linear pressure regime. Both ablation strategies were used for transcutaneous sonication of pre-defined treatment cells in the livers of 5 pigs in vivo. Temperature evolution in both the target area as well as the pre-focal muscle layer was monitored simultaneously using MR thermometry. Local energy absorption and thermal dose volumes were shown to be increased using the pulsed ablation strategy, while preserving healthy tissue in the near field of the acoustic beam. Respiratory motion compensation of both acoustic energy delivery and MR thermometry was applied through gating based on MR navigator echoes. Histopathology showed that confluent vacuolated thermal lesions were created when the pulsed ablation strategy was used. Additionally, it was shown that the heat sink effect caused by the presence of larger vessels could be overcome. The pulsed HIFU ablation strategy achieved an ablation rate of approximately 4 ml per hour in the in vivo porcine liver, without causing undesired damage to healthy tissues in the near field.

  14. Increasing the HIFU ablation rate through an MRI-guided sonication strategy using shock waves: feasibility in the in vivo porcine liver

    Science.gov (United States)

    Ramaekers, P.; de Greef, M.; van Breugel, J. M. M.; Moonen, C. T. W.; Ries, M.

    2016-02-01

    This study investigated whether an MR-guided pulsed HIFU ablation strategy could be implemented under clinical conditions, using a transducer designed for uterine fibroid ablation, to obtain an ablation rate that is sufficiently high for clinical abdominal HIFU therapy in highly perfused organs. A pulsed HIFU ablation strategy, aimed at increasing the energy absorption in the HIFU focal area by local shock wave formation in the non-linear pressure regime, was compared to an energy-equivalent continuous wave sonication strategy in the linear pressure regime. Both ablation strategies were used for transcutaneous sonication of pre-defined treatment cells in the livers of 5 pigs in vivo. Temperature evolution in both the target area as well as the pre-focal muscle layer was monitored simultaneously using MR thermometry. Local energy absorption and thermal dose volumes were shown to be increased using the pulsed ablation strategy, while preserving healthy tissue in the near field of the acoustic beam. Respiratory motion compensation of both acoustic energy delivery and MR thermometry was applied through gating based on MR navigator echoes. Histopathology showed that confluent vacuolated thermal lesions were created when the pulsed ablation strategy was used. Additionally, it was shown that the heat sink effect caused by the presence of larger vessels could be overcome. The pulsed HIFU ablation strategy achieved an ablation rate of approximately 4 ml per hour in the in vivo porcine liver, without causing undesired damage to healthy tissues in the near field.

  15. Gas-filled phospholipid nanoparticles conjugated with gadolinium play a role as a potential theragnostics for MR-guided HIFU ablation.

    Directory of Open Access Journals (Sweden)

    Se-Young Choi

    Full Text Available To develop a long-circulating theragnostics, meaning therapeutics and diagnostics for MR-guided HIFU ablation, we designed and prepared Gd-C(5F(12-phospholipid nanobubbles (PLNs 30-100 nm in diameter. The biochemical and physical characterization of Gd-C(5F(12-PLNs were performed. Since Gd-C(5F(12-PLN-50 (Φ = 50 nm and Gd-C(5F(12-PLN-100 (Φ = 100 nm enhanced the hyperthermal effect of HIFU size- and concentration-dependently in a tissue-mimicking phantom, its circulation, distribution, tumor accumulation and tumor ablation were examined in tumor-bearing mice. The plasma-half life of Gd-C(5F(12-PLNs was longer than 1.5 hrs. Gd-C(5F(12-PLNs mainly accumulated in the liver and the spleen, suggesting that they are slowly secreted through the hepatobiliary pathway. Monitored by the T1 signal intensity of MR, Gd-C(5F(12-PLNs accumulated in tumor tissues for 8 hours in mice. HIFU with Gd-C(5F(12-PLN-100 showed the increased tumor ablation area as compared with HIFU alone. The results suggest that Gd-C(5F(12-PLNs exhibit a potential theragnostics for MR-guided HIFU ablation.

  16. Measurement of hearing aid internal noise.

    Science.gov (United States)

    Lewis, James D; Goodman, Shawn S; Bentler, Ruth A

    2010-04-01

    Hearing aid equivalent input noise (EIN) measures assume the primary source of internal noise to be located prior to amplification and to be constant regardless of input level. EIN will underestimate internal noise in the case that noise is generated following amplification. The present study investigated the internal noise levels of six hearing aids (HAs). Concurrent with HA processing of a speech-like stimulus with both adaptive features (acoustic feedback cancellation, digital noise reduction, microphone directionality) enabled and disabled, internal noise was quantified for various stimulus levels as the variance across repeated trials. Changes in noise level as a function of stimulus level demonstrated that (1) generation of internal noise is not isolated to the microphone, (2) noise may be dependent on input level, and (3) certain adaptive features may contribute to internal noise. Quantifying internal noise as the variance of the output measures allows for noise to be measured under real-world processing conditions, accounts for all sources of noise, and is predictive of internal noise audibility. PMID:20370034

  17. Measurement of hearing aid internal noise1

    Science.gov (United States)

    Lewis, James D.; Goodman, Shawn S.; Bentler, Ruth A.

    2010-01-01

    Hearing aid equivalent input noise (EIN) measures assume the primary source of internal noise to be located prior to amplification and to be constant regardless of input level. EIN will underestimate internal noise in the case that noise is generated following amplification. The present study investigated the internal noise levels of six hearing aids (HAs). Concurrent with HA processing of a speech-like stimulus with both adaptive features (acoustic feedback cancellation, digital noise reduction, microphone directionality) enabled and disabled, internal noise was quantified for various stimulus levels as the variance across repeated trials. Changes in noise level as a function of stimulus level demonstrated that (1) generation of internal noise is not isolated to the microphone, (2) noise may be dependent on input level, and (3) certain adaptive features may contribute to internal noise. Quantifying internal noise as the variance of the output measures allows for noise to be measured under real-world processing conditions, accounts for all sources of noise, and is predictive of internal noise audibility. PMID:20370034

  18. High intensity focused ultrasound (HIFU) for treatment of T1/T2 prostate cancer

    Science.gov (United States)

    Sanghvi, N.; Gardner, T.; Koch, M.

    2003-04-01

    This FDA approved phase I/II clinical trial is to evaluate the safety and efficacy of the Sonablate device (Focus Surgery, Inc.) for the treatment of organ confined prostate cancer. 20 patients with biopsy proven prostate cancer, Gleason biopsy results at 6 months. Quality of life was assessed using the International Prostate Symptom Score, International Impotence and Erectile Function score, and the SF-36 health survey. The mean patient age is 62.0, Gleason score of 6.18, PSA of 5.2, and prostate size 26.0 gm. Mean PSA results were 5.62, 44, 20, 1.68, 0.87, and 0.44 ng/ml at screening, 48-72 hours, 14 days, 30 days, 90 days and 180 days, respectively. There was one patient (9%) with a positive TRUS biopsy at 6 months, which resulted in a retreatment. There were no rectal injuries. Average pre-treatment IPSS, IIEF, and SF-36 scores were 9.55, 16.1, and 103.5. At the 30 day follow-up, they were 18.3, 3, and 97.4, respectively. HIFU is a minimally invasive modality that achieves complete prostatic ablation and is efficacious in the treatment of low-stage prostate cancer.

  19. EXPERIENCE WITH A HISTOSCANNING APPARATUS USED IN THE DIAGNOSIS OF RECURRENT PROSTATE CANCER AFTER HIFU ABLATION

    Directory of Open Access Journals (Sweden)

    P. V. Glybochko

    2012-01-01

    Full Text Available The new potentialities of 3D transrectal ultrasound study were realized in a HistoScanning diagnostic unit. It has been used at the R.M. Fronshtein Urology Clinic, Research Institute of Uronephrology and Reproductive Health, I.M. Sechenov First Moscow State Medical University, since September 2011. A study of the sensitivity and specificity of the technique enrolled patients undergoing high-intensity focused ultrasound (HIFU ablation of the prostate of for its (PC in the period 1 to 7 years. Prostate biopsy study with subsequent histology was made to confirm the results of histoscanning. Statistical processing of the obtained data showed that the sensitivity and specificity of histoscanning were 96 −100 and 87.5 −100%, respectively. These results allow one to appreciate histoscanning as a highly sensitive technique that advantageously differs in its significance level and informative value from now routinely used methods. The study on the possibility of planning and monitoring patients after focal treatments for PC opens up great prospects in achieving a balance between the radicality of performed surgery and the maintenance of quality of life in patients.

  20. EXPERIENCE WITH A HISTOSCANNING APPARATUS USED IN THE DIAGNOSIS OF RECURRENT PROSTATE CANCER AFTER HIFU ABLATION

    Directory of Open Access Journals (Sweden)

    P. V. Glybochko

    2014-08-01

    Full Text Available The new potentialities of 3D transrectal ultrasound study were realized in a HistoScanning diagnostic unit. It has been used at the R.M. Fronshtein Urology Clinic, Research Institute of Uronephrology and Reproductive Health, I.M. Sechenov First Moscow State Medical University, since September 2011. A study of the sensitivity and specificity of the technique enrolled patients undergoing high-intensity focused ultrasound (HIFU ablation of the prostate of for its (PC in the period 1 to 7 years. Prostate biopsy study with subsequent histology was made to confirm the results of histoscanning. Statistical processing of the obtained data showed that the sensitivity and specificity of histoscanning were 96 −100 and 87.5 −100%, respectively. These results allow one to appreciate histoscanning as a highly sensitive technique that advantageously differs in its significance level and informative value from now routinely used methods. The study on the possibility of planning and monitoring patients after focal treatments for PC opens up great prospects in achieving a balance between the radicality of performed surgery and the maintenance of quality of life in patients.

  1. Feminizing noise

    OpenAIRE

    Thompson, Marie

    2014-01-01

    Marie will explore the relationship between constructions of femininity and noise, which is understood here as an affective transformative force, rather than simply as unwanted sound. She will suggest that ‘feminine’ noises are often deemed negative; not because of what they mean, but as a result of the transformations they threaten to induce. Marie will raise questions around essentialism – does talking of a feminine or feminized noise require us to adopt an essentialist position, or can an ...

  2. NOISE REGULATION

    OpenAIRE

    Cristina Voican; Constantin Stanescu

    2012-01-01

    Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. After the watershed passage of the United States Noise Control Act of 1972, other local and state governments passed further regulations. Although the UK and Japan enacted national laws in 1960 and 1967 respectively, these laws were not at all comprehensive or fully enforceable as to address generally rising ambient noise, enforceable...

  3. Noise suppression method for received waveform of satellite laser altimeter based on adaptive filter%利用自适应滤波星载激光测高仪回波噪声抑制方法

    Institute of Scientific and Technical Information of China (English)

    马跃; 李松; 周辉; 翁寅侃

    2012-01-01

    For satellite laser altimeter, the range between earth surface and satellite platform could be calculated, and the target characters could be inversed through extracting the parameters of received waveforms. The signal degradations emerge on the noise suppression process of returned pulse using the fixed width Gaussian filter, which influences seriously the extracting of the effective parameters. Based on the different statistical regularities among blocked signal, a new method is presented to estimate the mean and standard deviation of returned waveforms, and a width adaptive Gaussian filter is designed according to the statistical characters of returned pulse. The received digital counts data of GLAS were used to the Noise estimation, adaptive Gaussian filter, and Gaussian fitting were measured by GLAS system. The calculation results accord with GLAS official statstics. The errors of estimated noise mean were less than 0.4 digitized unit, and the effective Gaussian parameter errors are less dian 1%. The conclusion is that the returned pulse parameters of laser altimeter could be extracted effectively and accurately through this noise suppression method.%具有波形记录功能的星载激光测高仪,通过回波信息解算地表与卫星平台距离和反演地物特性.目前广泛采用的固定宽度高斯滤波方法在抑制回波噪声过程中造成有效信号变形,对提取信号有效参量造成严重干扰.根据分块信号统计特性不同的规律,提出了激光测高仪回波噪声均值和方差的估计方法;根据回波信号的统计特性,设计了一种宽度自适应的高斯滤波器.通过GLAS系统实测回波信号的噪声估计与自适应高斯滤波、高斯拟合,得到的波形处理结果与GLAS官方数据有很好的吻合度,噪声均值估计误差小于0.4个数字化仪单位,有效高斯参数计算误差小于1%.该方法能准确地提取波形参量,为地表高程解算和目标表面信息反演提供有效数据.

  4. 高强度聚焦超声(HIFU)肿瘤热消融技术的关键问题简析%Analysis of key problem of high intensity focused ultrasound (HIFU) thermal ablation technique

    Institute of Scientific and Technical Information of China (English)

    李发琪

    2011-01-01

    目的 1988年,王智彪萌发了用高强度聚焦超声(high intensity focused ultrasound,HIFU)从体外对体内肿瘤进行非侵入切除的灵感.在之后的10年中,他和他的团队在该领域提出了"生物学焦域"、"超声治疗剂量学"、"组织声环境"等概念.在实时超声监控、治疗系统优化、远程医疗系统、临床方案等方面突破了相应的关键技术壁垒.将HIFU治疗技术成功运用于外科治疗,在国际上积累了数量最多的临床病例.在该领域的设备研制、临床应用及若干基础研究方面走在了世界前列.%In 1988, Zhibiao Wang had an inspiration of ablating tumor in vivo non-invasively by high intensity focused ultrasound (HIFU). In the following 10 years, he and his team first proposed concepts such as "biological focal region", "ultrasound therapy dosimetry", "acoustic environment in tissue" and so on. They had broken down the key technical barriers in real-time ultrasound monitoring, treatment system optimization, telemedicine system, clinical protocols and other aspects, making HIFU therapy successfully applied to surgery and accumulated the largest number of clinical cases internationally. They have been playing a leading role around the world in equipment development, clinical application and some basic research in this field.

  5. Noise Traders

    OpenAIRE

    James Dow; Gary Gorton

    2006-01-01

    Noise traders are agents whose theoretical existence has been hypothesized as a way of solving certain fundamental problems in Financial Economics. We briefly review the literature on noise traders. The is an entry for The New Palgrave: A Dictionary of Economics, 2nd Edition (Palgrave Macmillan: New York), edited by Steven N. Durlauf and Lawrence E. Blume, forthcoming in 2008.

  6. Aircraft Noise

    Science.gov (United States)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  7. Speech endpoint detection in real noise environments

    Institute of Scientific and Technical Information of China (English)

    GUO Yanmeng; FU Qiang; YAN Yonghong

    2007-01-01

    A method of speech endpoint detection in environments of complicated additive noise is presented. Based on the analysis of noise, an adaptive model of stationary noise is proposed to detect the section where the signal is nonstationary. Then the voice is detected in this section by its harmonic structure, and the accurate endpoint is searched using energy.Compared with the typical algorithms, this algorithm operates reliably in most real noise environments.

  8. Towards noise classification of road pavements

    OpenAIRE

    Freitas, Elisabete F.; Paulo, Joel; Coelho, J. L. Bento; Pereira, Paulo A. A.

    2008-01-01

    Noise classification of road surfaces has been addressed in many European countries. This paper presents the first approach towards noise classification of Portuguese road pavements. In this early stage, it aims at establishing guidelines for decision makers to support their noise reduction policies and the development of a classification system adapted to the European recommendations. A ranking to provide guidance on tire-road noise emission levels for immediate use by decisio...

  9. ECG De-noising

    DEFF Research Database (Denmark)

    Kærgaard, Kevin; Jensen, Søren Hjøllund; Puthusserypady, Sadasivan

    2015-01-01

    Electrocardiogram (ECG) is a widely used noninvasive method to study the rhythmic activity of the heart and thereby to detect the abnormalities. However, these signals are often obscured by artifacts from various sources and minimization of these artifacts are of paramount important. This paper...... proposes two adaptive techniques, namely the EEMD-BLMS (Ensemble Empirical Mode Decomposition in conjunction with the Block Least Mean Square algorithm) and DWT-NN (Discrete Wavelet Transform followed by Neural Network) methods in minimizing the artifacts from recorded ECG signals, and compares...... their performance. These methods were first compared on two types of simulated noise corrupted ECG signals: Type-I (desired ECG+noise frequencies outside the ECG frequency band) and Type-II (ECG+noise frequencies both inside and outside the ECG frequency band). Subsequently, they were tested on real ECG recordings...

  10. Postoperative monitoring of prostate-specific antigen (PSA after treatment with high-intensive focused ultrasound (HIFU

    Directory of Open Access Journals (Sweden)

    Blyumberg B.I.

    2012-12-01

    Full Text Available Research objective: to estimate efficiency of treatment of prostate cancer using high-intensive focused ultrasound on the basis of laboratory analysis of postoperative level prostate-specific antigen (PSA. Objects of research. Objects of research consisted of 110 patients treated in urological clinic of Hospital n.a. S. R. Mirotvortsev (Saratov State Medical University during the period February, 2009 — March, 2012. Patients took 110 sessions of primary operative treatment of prostate cancer by HIFU therapy method. Technique and research methods. Concentration of PSA in blood changed in all patients every 1,5 month within 6 months after operation, irrespective of its kind (including after repeated HIFU, further — after every 3 month till one year, and later on after 6 months. We were guided by references of the International Consensus, which considers PSA level more than 0,5 ng/ml in blood after 3 months of treatment to be unsatisfactory result. We also headed for PSA level before treatment and oncological risk degree. Results. Median nadir formed 0,5 ng/ml PSA by 3 months after treatment. Patients demonstrated different indicators of PSA dynamics depending on oncological risk, stage and hormonal therapy management. Patients with low oncological risk had initially lower PSA concentration, further PSA concentration reached nadir level faster. At patients with widespread forms of prostate cancer accurate dependence of PSA concentration according to prevalence of process was traced. Time of PSA nadir amount did not differ and was marked as 12-14 weeks on average. At patients received hormonal therapy, lower value of PSA nadir was marked. The conclusion. Monitoring of PSA concentration (PSA nadir by 3 months, dynamics of PSA concentration change is of great importance in early revealing of relapse after prostate HIFU therapy. High level of PSA nadir and PSA growth according to time period are important prognostic factors.

  11. Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Rouviere, Olivier; Lyonnet, Denis [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Inserm, U556, Lyon (France); Girouin, Nicolas; Glas, Ludivine; Ben Cheikh, Alexandre [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Gelet, Albert [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Inserm, U556, Lyon (France); Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Pathology, Lyon (France); Rabilloud, Muriel [Hospices Civils de Lyon, Department of Biostatistics, Lyon (France); Universite de Lyon 1, UMR CNRS, Laboratoire Biostatistiques-Sante, Pierre-Benite (France); Chapelon, Jean-Yves [Inserm, U556, Lyon (France)

    2010-01-15

    The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies (''routine biopsies''); operator 2 obtained up to three cores per suspicious lesion on MRI (''targeted biopsies''). Seventy-seven suspicious lesions were detected on DCE images (n=52), T2w images (n=2) or both (n=23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p=0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p<0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05-3.64) and 1.38 (95% CI 1.13-1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue. (orig.)

  12. M-HIFU Inhibits Tumor Growth, Suppresses STAT3 Activity and Enhances Tumor Specific Immunity in a Transplant Tumor Model of Prostate Cancer

    OpenAIRE

    Xiaoyi Huang; Fang Yuan; Meihua Liang; Hui-Wen Lo; Shinohara, Mari L.; Cary Robertson; Pei Zhong

    2012-01-01

    OBJECTIVE: In this study, we explored the use of mechanical high intensity focused ultrasound (M-HIFU) as a neo-adjuvant therapy prior to surgical resection of the primary tumor. We also investigated the role of signal transducer and activator of transcription 3 (STAT3) in M-HIFU elicited anti-tumor immune response using a transplant tumor model of prostate cancer. METHODS: RM-9, a mouse prostate cancer cell line with constitutively activated STAT3, was inoculated subcutaneously in C57BL/6J m...

  13. Active noise canceling system for mechanically cooled germanium radiation detectors

    Science.gov (United States)

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  14. 信号点自适应生长算法和图像脉冲噪声的抑制%Signal adaptive growth algorithm and image impulse noise suppression

    Institute of Scientific and Technical Information of China (English)

    余旺盛; 侯志强

    2011-01-01

    针对脉冲噪声的抑制问题,提出了一种利用图像中未被污染的信号点向外自适应生长来消噪的快速自适应算法.算法首先利用信号阈值判决区间提取出输入图像中未被污染的信号点形成信号矩阵并作标记,同时计算信号密度;然后利用信号密度自适应控制信号点按一定幅度向外生长;最后对生长后的信号矩阵进行归一化处理和修正,得到滤波结果.与当前消噪算法相比,所提出的算法在消噪效果和复杂度方面优势较为明显.%This paper proposed a swift adaptive algorithm to restore images from impulse noise, by expanding the real signal pixels so as to smooth the noisy ones. First, the algorithm uses a critical region to distinguish signal pixels from noise and set a marked matrix. Then calculate the density of signal, which will be used to control the extent of growth adaptively. The final restored image will be obtained nearly after a simple correction on the expanded image matrix. The proposed algorithm exceeds the current ones markedly in both denoising effect and computational complexity.

  15. Chasing Noise

    OpenAIRE

    Mendel, Brock; Shleifer, Andrei

    2012-01-01

    We present a simple model in which rational but uninformed traders occasionally chase noise as if it were information, thereby amplifying sentiment shocks and moving prices away from fundamental values. We fill a theoretical gap in the literature by showing conditions under which noise traders can have an impact on market equilibrium disproportionate to their size in the market. The model offers a partial explanation for the surprisingly low market price of financial risk in the Spring of 2007.

  16. Crackling Noise

    OpenAIRE

    Sethna, James P.; Dahmen, Karin A.; Christopher R Myers

    2001-01-01

    Crackling noise arises when a system responds to changing external conditions through discrete, impulsive events spanning a broad range of sizes. A wide variety of physical systems exhibiting crackling noise have been studied, from earthquakes on faults to paper crumpling. Because these systems exhibit regular behavior over many decades of sizes, their behavior is likely independent of microscopic and macroscopic details, and progress can be made by the use of very simple models. The fact tha...

  17. Noise Bubbles

    OpenAIRE

    Mario Forni; Luca Gambetti; Marco Lippi; Luca Sala

    2014-01-01

    We introduce noisy information into a standard present value stock price model. Agents receive a noisy signal about the structural shock driving future dividend variations. The resulting equilibrium stock price includes a transitory component — the "noise bubble" — which can be responsible for boom and bust episodes unrelated to economic fundamentals. We propose a non-standard VAR procedure to estimate the structural shock and the "noise" shock, their impulse response functions and the bubble...

  18. Noise Residual Learning for Noise Modeling in Distributed Video Coding

    DEFF Research Database (Denmark)

    Luong, Huynh Van; Forchhammer, Søren

    2012-01-01

    Distributed video coding (DVC) is a coding paradigm which exploits the source statistics at the decoder side to reduce the complexity at the encoder. The noise model is one of the inherently difficult challenges in DVC. This paper considers Transform Domain Wyner-Ziv (TDWZ) coding and proposes...... noise residual learning techniques that take residues from previously decoded frames into account to estimate the decoding residue more precisely. Moreover, the techniques calculate a number of candidate noise residual distributions within a frame to adaptively optimize the soft side information during...

  19. Active Noise Control for Vehicle Exhaust Noise Reduction

    Institute of Scientific and Technical Information of China (English)

    李克强; 杨殿阁; 郑四发; 连小珉; 田中丈晴

    2003-01-01

    An active noise control (ANC) method was developed for exhaust noise reduction for medium-duty diesel trucks. A modified variable step size least mean squares (LMS) algorithm was used for the controller in a variable environment that considered the vehicle's acceleration characteristics. The variable step size time-based synchronized filtered-x LMS method (SFX-TB) used an adaptive algorithm that was more efficient than the conventional filtered-x LMS algorithm. The simulation and the experimental tests show that the control trackability and stability provided by the algorithm during acceleration enable the ANC system to effectively reduce the vehicle exhaust noise.

  20. Registration of CT to pre-treatment MRI for planning of MR-HIFU ablation treatment of painful bone metastases

    International Nuclear Information System (INIS)

    MR-HIFU is a new non-invasive treatment modality that can be used for palliation in patients with painful bone metastases. Since treatment strategies are mainly focused on the ablation of periosteal nerves, information on the presence and geometry of cortical bone influences the treatment strategy, both in determining the acoustic power and in avoiding safety issues related to far-field heating. Although MRI is available for imaging during treatment, CT is best used for examining the cortical bone. We present a registration method for registering CT and MR images of patients with bone metastases prior to therapy. CT and MRI data were obtained from nine patients with metastatic bone lesions at varying locations. A two-step registration approach was used, performing simultaneous rigid registration of all available MR images in the first step and an affine and deformable registration with an additional bone metric in the second step. The performance was evaluated using landmark annotation by clinical observers. An average registration error of 4.5 mm was obtained, which was comparable to the slice thickness of the data. The performance of the registration algorithm was satisfactory, even with differences in MRI acquisition parameters and for various anatomical sites. The obtained CT overlay is useful for treatment planning, as it allows an assessment of the integrity of the cortical bone. CT-MR registration is therefore recommended for HIFU treatment planning of patients with bone metastases. (paper)

  1. Registration of CT to pre-treatment MRI for planning of MR-HIFU ablation treatment of painful bone metastases

    Science.gov (United States)

    Noorda, Yolanda H.; Bartels, Lambertus W.; Huisman, Merel; Nijenhuis, Robbert J.; AAJ van den Bosch, Maurice; Pluim, Josien PW

    2014-08-01

    MR-HIFU is a new non-invasive treatment modality that can be used for palliation in patients with painful bone metastases. Since treatment strategies are mainly focused on the ablation of periosteal nerves, information on the presence and geometry of cortical bone influences the treatment strategy, both in determining the acoustic power and in avoiding safety issues related to far-field heating. Although MRI is available for imaging during treatment, CT is best used for examining the cortical bone. We present a registration method for registering CT and MR images of patients with bone metastases prior to therapy. CT and MRI data were obtained from nine patients with metastatic bone lesions at varying locations. A two-step registration approach was used, performing simultaneous rigid registration of all available MR images in the first step and an affine and deformable registration with an additional bone metric in the second step. The performance was evaluated using landmark annotation by clinical observers. An average registration error of 4.5 mm was obtained, which was comparable to the slice thickness of the data. The performance of the registration algorithm was satisfactory, even with differences in MRI acquisition parameters and for various anatomical sites. The obtained CT overlay is useful for treatment planning, as it allows an assessment of the integrity of the cortical bone. CT-MR registration is therefore recommended for HIFU treatment planning of patients with bone metastases.

  2. Voltage fluctuations in neurons: signal or noise?

    DEFF Research Database (Denmark)

    Yarom, Yosef; Hounsgaard, Jorn

    2011-01-01

    that allows and facilitates complex adaptive behavior in an unpredictable world. Here we review the growing experimental evidence that functional network activity is associated with intense fluctuations in membrane potential and spike timing. We trace origins and consequences of noise and variability. Finally......, we discuss noise-free neuronal signaling and detrimental and beneficial forms of noise in large-scale functional neural networks. Evidence that noise and variability in some cases go hand in hand with behavioral variability and increase behavioral choice, richness, and adaptability opens new avenues...

  3. Active noise cancellation in hearing devices

    DEFF Research Database (Denmark)

    2013-01-01

    connected to the at least one input transducer and adapted to process said electric audio signal by at least partially correcting for a hearing loss of a user; an output transducer adapted to generate from at least said processed electric audio signal a sound pressure in an ear canal of the user, whereby...... the generated sound pressure is at least partially corrected for the hearing loss of the user; ; the at least one active noise cancellation unit being adapted to provide an active noise cancellation signal adapted to perform active noise cancellation of an acoustical signal entering the ear canal in addition......Disclosed is a hearing device system comprising at least one hearing aid circuitry and at least one active noise cancellation unit, the at least one hearing aid circuitry comprises at least one input transducer adapted to convert a first audio signal to an electric audio signal; a signal processor...

  4. Optimization of wireless sensor communication channel based on adaptive noise cancellation%基于自适应噪声抵消的无线传感网络信道优化

    Institute of Scientific and Technical Information of China (English)

    龙清; 胡光波

    2016-01-01

    Wireless sensor network communication technology is widely applied in the field of Internet of things near field communication, underwater acoustic communication. The wireless sensor network communication channel often encounter the multi⁃path interference, which lead to an imbalance of channel. Based on the aboved, the paper develops the channel equalization model design. Proposed a wireless sensor communication channel based on adaptive noise cancellation optimization technique. Firstly, build the channel model of wireless sensor network communication. The wireless sensor network communication channel in the process of decay signal loss and various paths of the reorganization, the adaptive noise cancellation algorithm for channel multipath interference filter, combined with the least square ( RLS) criterion algorithm for wireless sensor communications channel equalization design. Simulation results show that using the communication channel equalization technique can effectively improve the quality of the wireless sensor network communication channel, reduce the communication transmission distortion and bit error rate, realize the adaptive channel equalization, therefore improve the anti⁃interference ability of communication.%无线传感器网络通信技术广泛应用在物联网近场通信、水声通信等领域。无线传感网络通信信道受到多途干扰,导致信道失衡,需要进行信道均衡模型设计。提出一种基于自适应噪声抵消的无线传感器网络通信信道优化技术,首先构建了无线传感器网络通信的信道模型,对无线传感器网络信道传播过程中衰减损失和各条路径的信号进行重组,采用自适应噪声抵消算法进行信道的多途干扰滤波,结合最小二乘( RLS)准则算法进行无线传感器网络通信信道均衡设计。仿真结果表明,采用该通信信道均衡技术能有效提高无线传感器网络通信的信道质量,降低通信传

  5. Cardiorespiratory Responses to Acoustic Noise in Belugas.

    Science.gov (United States)

    Lyamin, Oleg I; Korneva, Svetlana M; Rozhnov, Viatcheslav V; Mukhametov, Lev M

    2016-01-01

    To date, most research on the adverse effects of anthropogenic noise on marine mammals has focused on auditory and behavioral responses. Other responses have received little attention and are often ignored. In this study, the effect of acoustic noise on heart rate was examined in captive belugas. The data suggest that (1) heart rate can be used as a measure of physiological response (including stress) to noise in belugas and other cetaceans, (2) cardiac response is influenced by parameters of noise and adaptation to repeated exposure, and (3) cetacean calves are more vulnerable to the adverse effect of noise than adults. PMID:26611017

  6. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy.

    Science.gov (United States)

    Yan, Sijing; Lu, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-01-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic. PMID:27535093

  7. Ten-year Biochemical Disease-free Survival After High-intensity Focused Ultrasound (HIFU) for Localized Prostate Cancer: Comparison with Four Different Generation Devices

    Science.gov (United States)

    Uchida, T.; Nakano, M.; Shoji, S.; Omata, T.; Harano, Y.; Nagata, Y.; Usui, Y.; Terachi, T.

    2010-03-01

    HIFU has been recognized as a minimally invasive treatment option for localized prostate cancer. The purpose of the study was to assess with a long-term outcome of HIFU for prostate cancer. From January 1999, a total of 657 patients who had HIFU with at least 2 year follow-up were treated with four different types of Sonablate® (Focus Surgery, Indianapolis, USA) devices. Thirty-three patients were treated with Sonablate® 200 (S200) from 1999 to 2001, 406 patients with Sonablate® 500 (S500) from 2001 to 2005, 200 patients with Sonablate® 500 version 4 (V4) from 2005-2008 and 19 patients with Sonablate® 500 TCM (TCM) from 2007. Biochemical disease-free survival rate (bDFS) in all patients was 59% in 8 years. bDFS in 8 years in patients with S200 and S500 groups were 55% and 56%, and bDFS in 4 and 2 years in patients with V4 and TCM group were 72% and 84%, respectively. bDFS in low, intermediate, and high risk groups were 75%, 54%, and 43% in S200/S500 and 93%, 72%, and 58% in V4/TCM group. Negative prostate biopsy rate after HIFU was 97% in S200, 79% in S500, 94% in V4 and 100% in TCM group. HIFU as primary therapy for prostate cancer is indicated in patients with low- and intermediate-risk (T1-T2b N0M0 disease, a Gleason score of ⩽7, a PSA level of prostate volume of less than 40 mL. The rate of clinical outcome has significantly improved over the years due to technical improvements in the device.

  8. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy

    Science.gov (United States)

    Yan, Sijing; LU, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-01-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic. PMID:27535093

  9. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy

    Science.gov (United States)

    Yan, Sijing; Lu, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-08-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic.

  10. The rise of high intensity focused ultrasound (HIFU) non-invasive therapy for solid tumors%高强聚焦超声(HIFU)无创治疗肿瘤技术的崛起

    Institute of Scientific and Technical Information of China (English)

    冯若; 朱辉; 李发琪; 苏海兵; 陈迅

    2011-01-01

    20世纪40年代,美国学者首次提出了高强聚焦超声治疗技术的概念,并进行了初步的工程和临床研究.70、80年代间,治疗肿瘤的温热疗法曾盛行一时.90年代之后,高强聚焦超声外科肿瘤治疗技术在国际上重新崛起,我国率先推出了大型高强聚焦超声肿瘤治疗系统,并成功地应用于临床治疗乳腺癌、骨肿瘤、肝癌等多种实体肿瘤.迄今,该"JC型高强聚焦超声肿瘤治疗系统"已出口到英国、意大利、西班牙、日本、韩国等许多欧亚国家,在诸如欧洲肿瘤治疗中心等20多个医疗中心运行,治疗肿瘤患者达数万例.我国持续保持着引领世界超声无创治疗技术发展的领先地位.%In the 40 years of last centry American scientists put forward a concep of high intensity focused ultrasound (HIFU) therapeutic technique and had done some technical and clinical studies. Since 90 years the HIFU surgery technique treating tumors anew rised abruptly in the world. China firstly put out a comprehensive HIFU tumor treating sistem and successfully treated many solid tumors such as breast cancer, bone tumor, liver cancer etc.. Now the treating sistem has already exported to England, Italy,Spain, Japan, Colea etc. and treated tens thousands tumor patients. In the field of noninvasive ultrasound treating tumor technique China has continually kept the leading position in the world.

  11. Volumetric MR-HIFU ablation of uterine fibroids: Role of treatment cell size in the improvement of energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-sun [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Keserci, Bilgin [Philips Healthcare, Seoul (Korea, Republic of); Partanen, Ari [Philips Healthcare, Cleveland, OH (United States); Rhim, Hyunchul, E-mail: rhimhc@skku.edu [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Lim, Hyo K.; Park, Min Jung [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Koehler, Max O. [Philips Healthcare, Vantaa (Finland)

    2012-11-15

    Purpose: To evaluate the energy efficiency of differently sized volumetric ablations in MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of uterine fibroids. Materials and methods: This study was approved by the institutional review board and informed consent was obtained from all participants. Ten symptomatic uterine fibroids (mean diameter 8.9 cm) in 10 women (mean age 42.2) were treated by volumetric MR-HIFU ablation under binary feedback control. The energy efficiency (mm{sup 3}/J) of each sonication was calculated as the volume of lethal thermal dose (240 equivalent minutes at 43 Degree-Sign C) per unit acoustic energy applied. Operator-controllable parameters and signal intensity ratio of uterine fibroid to skeletal muscle on T2-weighted MR images were tested with univariate and multivariate analyses to discern which parameters significantly correlated with the ablation energy efficiency. Results: We analyzed a total of 236 sonications. The energy efficiency of the ablations was 0.42 {+-} 0.25 mm{sup 3}/J (range 0.004-1.18) with energy efficiency improving with the treatment cell size (4 mm, 0.06 {+-} 0.06 mm{sup 3}/J; 8 mm, 0.29 {+-} 0.12 mm{sup 3}/J; 12 mm, 0.58 {+-} 0.18 mm{sup 3}/J; 16 mm, 0.91 {+-} 0.17 mm{sup 3}/J). Treatment cell size (r = 0.814, p < 0.001), distance of ultrasound propagation (r = -0.151, p = 0.020), sonication frequency (1.2 or 1.45 MHz; p < 0.001), and signal intensity ratio (r = -0.205, p = 0.002) proved to be significant by univariate analysis, while multivariate analysis revealed treatment cell size (B = 0.075, p < 0.001), US propagation distance (B = -6.928, p < 0.001), and signal intensity ratio (B = -0.024, p = 0.001) to be independently significant. Conclusion: Energy efficiency in volumetric MR-HIFU ablation of uterine fibroids improves with increased treatment cell size, independent of other significant contributors such as distance of ultrasound propagation or signal intensity of the tumor on T2-weighted MR

  12. Improving Gabor Noise

    OpenAIRE

    Lagae, Ares; Lefebvre, Sylvain; Dutré, Philip

    2011-01-01

    We have recently proposed a new procedural noise function, Gabor noise, which offers a combination of properties not found in existing noise functions. In this paper, we present three significant improvements to Gabor noise: (1) an isotropic kernel for Gabor noise, which speeds up isotropic Gabor noise with a factor of roughly two, (2) an error analysis of Gabor noise, which relates the kernel truncation radius to the relative error of the noise, and (3) spatially varying Gabor noise, which e...

  13. Active Noise Feedback Control Using a Neural Network

    Directory of Open Access Journals (Sweden)

    Zhang Qizhi

    2001-01-01

    Full Text Available The active noise control (ANC is discussed. Many digital ANC systems often based on the filter-x algorithm for finite impulse response (FIR filter use adaptive filtering techniques. But if the primary noise path is nonlinear, the control system based on adaptive filter technology will be invalid. In this paper, an adaptive active nonlinear noise feedback control approach using a neural network is derived. The feedback control system drives a secondary signal to destructively interfere with the original noise to cut down the noise power. An on-line learning algorithm based on the error gradient descent method was proposed, and the local stability of closed loop system is proved using the discrete Lyapunov function. A nonlinear simulation example shows that the adaptive active noise feedback control method based on a neural network is very effective to the nonlinear noise control.

  14. An MR-compliant phased-array HIFU transducer with augmented steering range, dedicated to abdominal thermotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Auboiroux, Vincent [Inserm, U556, Lyon, F-69003 (France); Dumont, Erik [Image Guided Therapy, Pessac, Bordeaux (France); Petrusca, Lorena; Salomir, Rares [Faculty of Medicine, University of Geneva (Switzerland); Viallon, Magalie, E-mail: vincent.auboiroux@unige.ch [Radiology Department, University Hospital of Geneva, Geneva (Switzerland)

    2011-06-21

    A novel architecture for a phased-array high intensity focused ultrasound (HIFU) device was investigated, aiming to increase the capabilities of electronic steering without reducing the size of the elementary emitters. The principal medical application expected to benefit from these developments is the time-effective sonication of large tumours in moving organs. The underlying principle consists of dividing the full array of transducers into multiple sub-arrays of different resonance frequencies, with the reorientation of these individual emitters, such that each sub-array can focus within a given spatial zone. To enable magnetic resonance (MR) compatibility of the device and the number of output channels from the RF generator to be halved, a passive spectral multiplexing technique was used, consisting of parallel wiring of frequency-shifted paired piezoceramic emitters with intrinsic narrow-band response. Two families of 64 emitters (circular, 5 mm diameter) were mounted, with optimum efficiency at 0.96 and 1.03 MHz, respectively. Two different prototypes of the HIFU device were built and tested, each incorporating the same two families of emitters, but differing in the shape of the rapid prototyping plastic support that accommodated the transducers (spherical cap with radius of curvature/aperture of 130 mm/150 mm and, respectively, 80 mm/110 mm). Acoustic measurements, MR-acoustic radiation force imaging (ex vivo) and MR-thermometry (ex vivo and in vivo) were used for the characterization of the prototypes. Experimental results demonstrated an augmentation of the steering range by 80% along one preferentially chosen axis, compared to a classic spherical array of the same total number of elements. The electric power density provided to the piezoceramic transducers exceeded 50 W cm{sup -2} CW, without circulation of coolant water. Another important advantage of the current approach is the versatility of reshaping the array at low cost.

  15. 基于EMD和ANFIS的自适应噪声消除研究%STUDY ON AN ADAPTIVE NOISE CANCELLATION BASED ON EMD (EMPIRICAL MODE DECOMPOSITION) AND ANFIS (ADAPTIVE NEURO-FUZZY INFERENCE SYSTEM)

    Institute of Scientific and Technical Information of China (English)

    徐春生; 王太勇

    2009-01-01

    对于混入色噪声的混合信号,如果可以通过测量得到产生色噪声的白噪声,对白噪声进行非线性训练即可逼近色噪声,达到非线性滤波的目的.自适应模糊推理系统(adaptive neuro-fuzzy unference system,ANFIS)可以实现上述非线性逼近.文中在上述算法的基础上,提出一种EMD(empirical mode decomposition)-ANFIS的自适应色噪声消除方法,首先对混合信号进行EMD分解,得到各个内禀模态函数分量(intrinsic mode function, IMF),然后对分解得到的内禀模态分量进行ANFIS模糊消噪,最后对消噪后的各个分量信号进行叠加.由于所得内禀模态函数为近似平稳信号,且图形越来越趋于平缓,减小了ANFIS方法的逼近难度.在混合信号信噪比为2.840 7 dB时,经过EMD-ANFIS消噪后的估计误差比只经过ANFIS消噪后的估计误差减少11.74 dB,证明EMD-ANFIS方法的有效性.

  16. Relativistic Noise

    OpenAIRE

    Kapusta, Joseph; Mueller, Berndt; Stephanov, Misha

    2012-01-01

    The relativistic theory of hydrodynamic fluctuations, or noise, is derived and applied to high energy heavy ion collisions. These fluctuations are inherent in any space-time varying system and are in addition to initial state fluctuations. We illustrate the effects with the boost-invariant Bjorken solution to the hydrodynamic equations. Long range correlations in rapidity are induced by propagation of sound modes. The magnitude of these correlations are directly proportional to the viscositie...

  17. Skewed Noise

    OpenAIRE

    David Dillenberger; Uzi Segal

    2013-01-01

    Experimental evidence suggests that individuals who face an asymmetric distribution over the likelihood of a specific event might actually prefer not to know the exact value of this probability. We address these findings by studying a decision maker who has recursive, non-expected utility preferences over two-stage lotteries. For a binary lottery that yields the better outcome with probability p, we identify noise around p with a compound lottery that induces a probability distribution over t...

  18. 11C choline PET guided salvage radiotherapy with volumetric modulation arc therapy and hypofractionation for recurrent prostate cancer after HIFU failure: preliminary results of tolerability and acute toxicity.

    Science.gov (United States)

    Alongi, Filippo; Liardo, Rocco L E; Iftode, Cristina; Lopci, Egesta; Villa, Elisa; Comito, Tiziana; Tozzi, Angelo; Navarria, Pierina; Ascolese, Anna M; Mancosu, Pietro; Tomatis, Stefano; Bellorofonte, Carlo; Arturo, Chiti; Scorsetti, Marta

    2014-10-01

    The purpose of this work was to evaluate tolerance, feasibility and acute toxicity in patients undergoing salvage radiotherapy after high-intensity focused ultrasound (HIFU) failure. From 2005 to 2011 a total of 15 patients were treated with HIFU as primary radical treatment. Between July 2011 and February 2013, all 15 patients presented biochemical relapse after HIFU and 11C choline PET documenting intrapostatic-only failure. Salvage EBRT was performed with moderate hypofractionation schedule in 28 fractions with volumetric modulation arc therapy (VMAT). Genito-urinary (GU) and rectal and bowel toxicity were scored by common terminology criteria for adverse events version 4 (CTCAE V.4) scale. Biochemical response was assessed by ASTRO Phoenix criteria. Median age of patients was 67 years (range: 53-85). The median Gleason score was 7 (range: 6-9). The median prostate specific antigen (PSA) at the time of biochemical relapse after HIFU was 5.2 ng/mL (range: 2-64.2). Seven of the 15 patients received androgen deprivation therapy (ADT) started after HIFU failure, interrupted before 11C choline PET and radiotherapy. Median prescribed dose was 71.4 Gy (range: 71.4-74.2 Gy) in 28 fractions. No radiation related major upper gastrointestinal (GI), rectal and GU toxicity were experienced. GU, acute grade 1 and grade 2 toxicities were recorded in 7/15 and 4/15 respectively; bowel acute grade 1 and grade 2 toxicities in 4/15 and 1/15; rectal acute grade 1 and grade 2 toxicities in 3/15 and 2/15 respectively. No grade 3 or greater acute or late toxicities occurred. Biochemical control was assessed in 12/15 (80%) patients. With a median follow up of 12 months, three out of 15 patients, with biochemical relapse, showed lymph-nodal recurrence. Our early clinical results and biochemical data confirm the feasibility and show a good tolerance of the 11C choline PET guided salvage radiation therapy after HIFU failure. The findings of low acute toxicity is encouraging, but longer

  19. Noise in Optical Amplifiers

    DEFF Research Database (Denmark)

    Jeppesen, Palle

    1997-01-01

    Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived.......Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived....

  20. Low noise road surfaces

    OpenAIRE

    Bolčina, Matjaž

    2014-01-01

    Noise is everywhere. Noise is a sound that makes people stressful and irritate. It often couses sleep disorders and also health problems like different cardiovascular disorders, hearing loss…In most cases traffic noise is the most disturbing. There are different ways to prevent people from traffic noise like building noise barriers and insulation of facades. However noise barriers and insulation of facades do not prevent noise formation, but are lowering existing noise. Another disadvantage i...

  1. Experimental investigation of thermal effects in HIFU-based external valvuloplasty with a non-spherical transducer, using high-resolution MR thermometry

    International Nuclear Information System (INIS)

    Real-time image-guided extracorporeal high intensity focused ultrasound (HIFU) has been suggested for minimally invasive treatment of valvular dysfunction in the saphenous vein. Local application of heat on the perimeter of the valve zone was previously reported to induce a partial shrinkage of the collagen, which may correct valvular function. In our study, a novel MR compatible HIFU device has been investigated. This device is based on a non-spherical geometry, with two active elements that create a focusing line which is orthogonal to the beam main axis, aiming to cover the valve longitudinally. The prototype performance was characterized by electro-acoustical measurements of the pressure field and by high-resolution MR thermometry. Pressure and thermal fields were found in good agreement with the theoretical predictions. To investigate the therapeutic potential, fresh samples of excised human veins were filled with an agarose gel, embedded in porcine muscle and exposed to HIFU. The power level applied during a fixed duration of 30 s was varied such that the absolute temperature at focus ranged between 52 deg. C and 83 deg. C. Targeting was achieved under MR guidance using a MR compatible XZ positioning system. A dedicated waterproof miniature loop coil was specifically built to achieve high-resolution MRI image-based targeting (0.25 mm x 0.25 mm x 3 mm voxel) and thermometry (0.4 mm x 0.4 mm x 4 mm voxel). The vein wall was clearly identified on MR images before and after HIFU treatment. The thermal buildup created by the non-spherical transducer could be characterized from MR thermometry data. Shrinkage of the vein wall (above 65 deg. C) was determined by absolute temperature and was not a cumulative thermal dose effect.

  2. Nonequilibrium Spin Noise and Noise of Susceptibility

    OpenAIRE

    Schad, Pablo; Narozhny, Boris N.; Schön, Gerd; Shnirman, Alexander

    2014-01-01

    We analyze out-of-equilibrium fluctuations in a driven spin system and relate them to the noise of spin susceptibility. In the spirit of the linear response theory we further relate the noise of susceptibility to a $4$-spin correlation function in equilibrium. We show that, in contrast to the second noise (noise of noise), the noise of susceptibility is a direct measure of non-Gaussian fluctuations in the system. We develop a general framework for calculating the noise of susceptibility using...

  3. MR thermometry analysis program for laser- or high-intensity focused ultrasound (HIFU)-induced heating at a clinical MR scanner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Ju; Jeong, Ki Young; Oh, Seung Jae; Park, Eun Hae; Lee, Young Han; Suh, Jin Suck [Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Dae Hong [National Cancer Center, Goyang (Korea, Republic of)

    2014-12-15

    Magnetic resonance (MR) thermometry is a noninvasive method for monitoring local temperature change during thermal therapy. In this study, a MR temperature analysis program was established for a laser with gold nanorods (GNRs) and high-intensity focused ultrasound (HIFU)-induced heating MR thermometry. The MR temperature map was reconstructed using the water proton resonance frequency (PRF) method. The temperature-sensitive phase difference was acquired by using complex number subtraction instead of direct phase subtraction in order to avoid another phase unwrapping process. A temperature map-analyzing program was developed and implemented in IDL (Interactive Data Language) for effective temperature monitoring. This one program was applied to two different heating devices at a clinical MR scanner. All images were acquired with the fast spoiled gradient echo (fSPGR) pulse sequence on a 3.0 T GE Discovery MR750 scanner with an 8-channel knee array coil or with a home-built small surface coil. The analyzed temperature values were confirmed by using values simultaneously measured with an optical temperature probe (R{sup 2} = 0.996). The temperature change in small samples induced by a laser or by HIFU was analyzed by using a raw data, that consisted of complex numbers. This study shows that our MR thermometry analysis program can be used for thermal therapy study with a laser or HIFU at a clinical MR scanner. It can also be applied to temperature monitoring for any other thermal therapy based on the PRF method.

  4. Multi-Angle Switched HIFU: A New Ultrasound Device for Controlled Non-Invasive Induction of Small Spherical Ablation Zones—Simulation and Ex-Vivo Results

    Science.gov (United States)

    Novák, Petr; Jamshidi-Parsian, Azemat; Benson, Donny G.; Webber, Jessica S.; Moros, Eduardo G.; Shafirstein, Gal; Griffin, Robert J.

    2009-04-01

    Current HIFU devices produce elongated elliptical lesions (cigar shaped) in a single energy deposition. This prohibits the effective use of HIFU in small animal research as well as in clinical treatment where small volumes of tissue surrounded by critical structures need to be destroyed. We developed an ultrasound ablation device that non-invasively creates spheroidal lesions of an arbitrary diameter of up to 1 cm in a depth of up to 5 cm. The device consists of two focused ultrasound transducers aimed to the ablation target volume from two directions at a 90 degree angle. The operation of the transducers is switched back and forth so that only one transducer is energized at a time. A transient analysis of this ablation approach was performed using coupled simulations of acoustical pressure distributions, resulting temperature distributions, and thermal dose deposited to soft tissue. A prototype of the device was developed and tested in-vitro in a phantom and later in ex-vivo experiments in pig liver. The experimental results agreed with the numerical simulations and confirmed the ability of the multi-angle switched HIFU (MASH) device to create small spheroidal lesions in soft tissue within 2 minutes without significantly affecting the surrounding tissues.

  5. An improved probe noise approach for acoustic feedback cancellation

    DEFF Research Database (Denmark)

    Guo, Meng; Jensen, Søren Holdt; Jensen, Jesper

    2012-01-01

    The perhaps most challenging problem in acoustic feedback cancellation using adaptive filters is the bias problem. It is well-known that a probe noise approach can effectively prevent this problem. However, when the probe noise must be inaudible and the steady-state error of the adaptive filter...... must be unchanged, this approach causes a significantly decreased convergence rate of the adaptive filter, and might thereby be less useful in practical applications. In this work, we propose a new probe noise approach which significantly increases the convergence rate while maintaining the steady-state...... error of the adaptive algorithm in a multiple-microphone and single-loudspeaker audio system. This is obtained through a specifically designed probe noise signal and a corresponding probe noise enhancement strategy. We show the effects of the proposed probe noise approach by deriving analytical...

  6. Multichannel active noise control systems and algorithms for reduction on broadband noise

    NARCIS (Netherlands)

    Berkhoff, A.P.; Wesselink, J.M.

    2007-01-01

    Active noise contral systems for braadband noise reduction require substantial computing power, especially for multichannel systems and adaptive controllers. Furthermore, speed of convergence can be an issue as weil. In this paper, methods and techniques are described that are able to reduce the com

  7. Development of a Voice Activity Controlled Noise Canceller

    Directory of Open Access Journals (Sweden)

    Aini Hussain

    2012-05-01

    Full Text Available In this paper, a variable threshold voice activity detector (VAD is developed to control the operation of a two-sensor adaptive noise canceller (ANC. The VAD prohibits the reference input of the ANC from containing some strength of actual speech signal during adaptation periods. The novelty of this approach resides in using the residual output from the noise canceller to control the decisions made by the VAD. Thresholds of full-band energy and zero-crossing features are adjusted according to the residual output of the adaptive filter. Performance evaluation of the proposed approach is quoted in terms of signal to noise ratio improvements as well mean square error (MSE convergence of the ANC. The new approach showed an improved noise cancellation performance when tested under several types of environmental noise. Furthermore, the computational power of the adaptive process is reduced since the output of the adaptive filter is efficiently calculated only during non-speech periods.

  8. Kombination aus TUR-P und hochintensiv fokussiertem Ultraschall (HIFU zur Behandlung des lokoregionären Prostatakarzinoms - Erfahrungen mit 70 Patienten

    Directory of Open Access Journals (Sweden)

    Walter B

    2004-01-01

    Full Text Available Ziel: HIFU ist eine minimal invasive Behandlungsalternative des lokoregionären Prostatakarzinoms. Eine vorgeschaltete TUR-P verkleinert die Drüse, insbesondere die meist karzinomfreie Transitionalzone, so daß sich die Behandlung im Idealfall ganz auf die peripheren Drüsenanteile konzentrieren kann. Zudem sollte durch die Resektion der Zeitraum einer allfälligen ödembedingten postoperativen Blasenauslaßobstruktion verkürzt werden. Patienten und Methoden: Wir haben 70 Patienten mit bioptisch gesichertem, lokoregionärem Prostatakarzinom (T1/T2, N0, M0 mit einer Kombination aus TUR-P und HIFU (Ablatherm-Gerät, EDAP, Lyon, Frankreich behandelt. Die Einschlußkriterien umfaßten einen PSA-Wert 15 ng/ml und einen Gleason-Score 7. Das mittlere Patientenalter lag bei 66,78 (± 6,3 Jahren, der mittlere PSA-Wert bei 7,25 ± (3,5 ng/ml, und der mittlere Gleason-Score bei 5,1 (± 1,2. Das initiale Prostatavolumen lag bei 32 (± 11,6 cm3 und wurde durch die TUR-P auf 22,8 (± 7,2 cm3 reduziert. Das Nachsorgeintervall betrug durchschnittlich 15 (± 6,8 Monate. Das Follow-up beinhaltete bei allen Patienten PSA-Kontrollen und Biopsien der Restdrüse. Die Daten von allen 70 Patienten konnten ausgewertet werden. Ergebnisse: Der PSA-Nadir lag im Mittel bei 0,14 (± 0,34 ng/ml und wurde nach 3 Monaten erreicht. Der durchschnittliche PSA-Wert der letzten Kontrolle betrug 0,21 (± 0,38 ng/ml. 94 % der Patienten zeigten negative Kontrollbiopsien. Die postoperative Katheterverweildauer lag bei durchschnittlich 7 Tagen (± 4,2. Bei 13,6 % der Patienten trat eine urodynamisch wirksame Blasenauslaßobstruktion auf, bei der konsekutiv endoskopisch interveniert werden mußte. IPS-Score und Quality of Life Index haben sich durch die Behandlung nicht signifikant geändert. Diskussion: Durch die vorgeschaltete TUR-P ist die Drüsengröße kaum noch ein Ausschlußkriterium für eine HIFU. Die postoperative ödembedingte infravesikale Obstruktion läßt sich gegen

  9. Inhibitory noise

    Directory of Open Access Journals (Sweden)

    Alain Destexhe

    2010-03-01

    Full Text Available Cortical neurons in vivo may operate in high-conductance states, in which the major part of the neuron's input conductance is due to synaptic activity, sometimes several-fold larger than the resting conductance. We examine here the contribution of inhibition in such high-conductance states. At the level of the absolute conductance values, several studies have shown that cortical neurons in vivo are characterized by strong inhibitory conductances. However, conductances are balanced and spiking activity is mostly determined by fluctuations, but not much is known about excitatory and inhibitory contributions to these fluctuations. Models and dynamic-clamp experiments show that, during high-conductance states, spikes are mainly determined by fluctuations of inhibition, or by inhibitory noise. This stands in contrast to low-conductance states, in which excitatory conductances determine spiking activity. To determine these contributions from experimental data, maximum likelihood methods can be designed and applied to intracellular recordings in vivo. Such methods indicate that action potentials are indeed mostly correlated with inhibitory fluctuations in awake animals. These results argue for a determinant role for inhibitory fluctuations in evoking spikes, and do not support feed-forward modes of processing, for which opposite patterns are predicted.

  10. Effect of train noise on sleep for people living in houses bordering the railway line

    CERN Document Server

    Vernet, M

    1979-01-01

    Disturbance of sleep by train and road noises was studied through in situ physiological recordings. For the same value of L/sub eq/ three times as many disturbances due to the noise from road traffic were found as there were due to the train noise. The data on sleep reactions for all the noise events do not show a better train noise adaptation than those for the road noise. (8 refs).

  11. Noise and Hearing Protection

    Science.gov (United States)

    ... Meeting Calendar Find an ENT Doctor Near You Noise and Hearing Protection Noise and Hearing Protection Patient ... it is. How can I tell if a noise is dangerous? People differ in their sensitivity to ...

  12. Adapting directives on noise emission reduction in fisheries and marine transport.Its impact on the economy; Adaptacion de las directivas sobre reduccion de emisiones acusticas en la pesca y transporte maritimo. Su impacto en la economia

    Energy Technology Data Exchange (ETDEWEB)

    Beltran Palomo, P.

    2012-07-01

    The environmental impact assessment of a vessel requires the introduction of a new indicator called Noise and Vibration Full Signature. This indicator includes: N and V on board, noise radiated to harbour and underwater radiated noise. The last one has became not only the most remarkable novelty but also the biggest technical challenge to be solved. This manuscript details the technical-economical, also in terms of feasibility, consequences which this environmental policy will imply in the european marine sector. As a counterpoint, it is detailed the success of the spanish marine sector in the shipbuilding of silent vessels. (Author)

  13. Noise-Measuring Method

    DEFF Research Database (Denmark)

    Diamond, J. M.

    1965-01-01

    A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test.......A noise-measuring method based on the use of a calibrated noise generator and an output meter with a special scale is described. The method eliminates the effect of noise contributions occurring in the circuits following the device under test....

  14. Noise Exclusion Ability in Infants

    Directory of Open Access Journals (Sweden)

    Geroldene Tsui

    2011-05-01

    Full Text Available An important perceptual ability is to filter out background distractions from relevant information. However, prior research has not identified when this begins in humans. Our study aims to investigate whether noise exclusion ability occurs in infancy. Infants' contrast sensitivity function (CSF was measured by a Baynesian adaptive inference method. Infants' attention was directed to the middle of a monitor where an 8.72 degree static Gabor grating was presented on the left or right side of the monitor. In half the trials, the grating was presented against a gray background; in the other half, against a 16% contrast random-dot noise background. The experimenter and two independent coders judged which side the infants gazed at (force-choice preferential looking paradigm. One-hundred babies aged from 4 to 10 months satisfied the 70% interrater consistency criterion for inclusion. Four parameters defined the best-fitted CSF for each infant. Of these, peak spatial frequency, bandwidth and truncation of CSF were similar in conditions with and without noise. The peak gain estimate was most significantly impaired by external noise, but a marked 31% improvement was observed in 7- to 10-month-olds. This may be the first sign of development of human's noise exclusion ability, and is worth further study.

  15. Automotive active noise control (ANC) system. Jidoshayo active noise control (ANC) system

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, S. (Nissan Motor Co. Ltd., Tokyo (Japan))

    1992-11-25

    This paper introduces a successful development of an active noise control (ANC) system that selects and controls noise in an automobile compartment. This is a system that Nissan has developed for practical use for the first time in the world by using an adaptive control theory and a digital signal processor (DSP) that uses ultra-high speed operating elements. The principle for noise silencing in the ANC system utilizes interference of cyclic amplitude of sound with opposite phase. Sounds in an automobile include informative sounds, agreeable sounds, and noise, and combinations of these sounds work complexly on people in a car, of which extent varies depending on individuals. The adaptive control minimizes sounds picked up by a microphone into controlled speaker sound via an multiple error filtered algorithm (MEF-[sub X]LMS) and an adaptive digital filter. Major components of the system include a microphone, a speaker, and a control unit (comprising the adaptive algorithm and the adaptive filter), all having been developed newly. A DSP that operates on ultra-high speed operating elements was used for speedy compliance with complex algorithms, so that the controlled sound combined of engine noise with compartment sound field can be calculated. The noise was reduced by more than 10 dB at maximum. 7 figs.

  16. Low Complexity Expert Dependent Noise Filtration Algorithm

    OpenAIRE

    Sasi Rekha.Sanivarapu; P.Padmaja Priyadarsini; Dr.M.VenuGopala Rao

    2012-01-01

    In this paper, a flexible and robust wavelet based image denoising algorithm is proposed, which adapts itself to various and unknown types of noise as well as to the preference of the medical expert: a single tuning parameter is used to balance the preservation of relevant details against the degree of noise reduction. We employ a preliminary coefficient classification technique to empirically estimate the statistical distributions of the coefficients that represent useful image features on t...

  17. The effects of noise on performance

    Science.gov (United States)

    Suter, Alice H.

    1989-06-01

    The effects of noise on task performance are quite complex, and not as predictable as other noise effects. They are often affected by non-acoustical factors, such as biological and psychological state, as well as external factors such as task complexity and the presence of other stressors. This report describes the rationale and some of the problems inherent in noise and performance research, as well as theories on the mechanisms of effects, and summarizes the various effects. Research on noise and vision suggests some effects from high noise levels on thresholds of sensitivity, critical flicker fusion, and visual field shifts. Small but reliable effects have been demonstrated on vestibular function, expecially with asymmetric exposures. Motor performance usually adapts with repeated or prolonged exposure, but high noise levels can show persistent decrements. Some startle responses, notably the eye-blink response, do not habituate. With respect to task variables, noise has little effect on simple tasks, and can even improve performance on monotonous tasks. Tasks requiring continuous performance may be disrupted, especially by noise levels over 100 dB and if the job requires a high level of sustained performance. Intellectual function is not usually affected, but vigilance tasks are susceptible to noise, particularly under certain conditions. Complex tasks requiring more than one activity are much more likely to be disrupted than simple tasks.

  18. Improved Noise Minimum Statistics Estimation Algorithm for Using in a Speech-Passing Noise-Rejecting Headset

    Science.gov (United States)

    Seyedtabaee, Saeed; Moazami Goodarzi, Hamze

    2010-12-01

    This paper deals with configuration of an algorithm to be used in a speech-passing angle grinder noise-canceling headset. Angle grinder noise is annoying and interrupts ordinary oral communication. Meaning that, low SNR noisy condition is ahead. Since variation in angle grinder working condition changes noise statistics, the noise will be nonstationary with possible jumps in its power. Studies are conducted for picking an appropriate algorithm. A modified version of the well-known spectral subtraction shows superior performance against alternate methods. Noise estimation is calculated through a multi-band fast adapting scheme. The algorithm is adapted very quickly to the non-stationary noise environment while inflecting minimum musical noise and speech distortion on the processed signal. Objective and subjective measures illustrating the performance of the proposed method are introduced.

  19. Can Noise Kill People?

    Institute of Scientific and Technical Information of China (English)

    刘玲娣

    2007-01-01

    Someone is singing next door,but you feel unhappy because her singing is just making a noise.We know that too much noise makes people feel terrible. Scientists are still trying to find out more about noise,but already it is known that a noise of over 85 decibels can make some people tired and anxious.

  20. Immersion Into Noise

    OpenAIRE

    Nechvatal, Joseph

    2011-01-01

    Joseph Nechvatal's Immersion Into Noise investigates multiple aspects of cultural noise by applying our audio understanding of noise to the visual, architectual and cognative domains. The author takes the reader through phenomenal aspects of the art of noise into algorithmic and network contexts, beginning in the Abside of the Grotte de Lascaux.

  1. Noise, Health, and Architecture.

    Science.gov (United States)

    Beranek, Leo L.

    There is reasonable agreement that hearing impairment is related to noise exposure. This hearing loss due to noise is considered a serious health injury, but there is still difficulty in delineating the importance of noise related to people's general non-auditory well-being and health. Beside hearing loss, noise inhibits satisfactory speech…

  2. Inhibition of Fuze Noise AM Interference Based on Adaptive Filter%基于自适应滤波的引信噪声调幅干扰抑制

    Institute of Scientific and Technical Information of China (English)

    宋扬; 关赛飞; 路翠华; 刘华章

    2013-01-01

    噪声调幅干扰是一种有效的压制性干扰,可压制近炸无线电引信对目标信息的获取。为提高连续波多普勒无线电引信抗噪声调幅干扰的能力,将单频率自适应陷波器应用到连续波多普勒引信中,对噪声调幅干扰进行抑制。分析了噪声干扰抑制原理,并对噪声干扰抑制效果进行了仿真。仿真结果表明:SJR=-10 dB时,仍然能达到很好的噪声调幅干扰抑制效果。%Noise AM interference can prevent a proximity radio fuze form getting target information. In order to improve the ability of continuous-wave Doppler fuze to anti-noise AM interference, notch filter was adopted to suppress noise AM in-terference. Principle of anti-noise jamming was analyzed and the suppressing effect was simulated. The simulation results showed that when SNR=-10 dB, noise AM interference could still be suppressed effectively.

  3. Mechanics of underwater noise

    CERN Document Server

    Ross, Donald

    1976-01-01

    Mechanics of Underwater Noise elucidates the basic mechanisms by which noise is generated, transmitted by structures and radiated into the sea. Organized into 10 chapters, this book begins with a description of noise, decibels and levels, significance of spectra, and passive sonar equation. Subsequent chapters discuss sound waves in liquids; acoustic radiation fundamentals; wind-generated ocean ambient noise; vibration isolation and structural damping; and radiation by plate flexural vibrations. Other chapters address cavitation, propeller cavitation noise, radiation by fluctuating-force (dipo

  4. Noise sustained propagation: Local versus global noise

    OpenAIRE

    Locher, M.; Chatterjee, N.; Marchesoni, F.; Ditto, W. L.; Hunt, E. R.

    2000-01-01

    We expand on prior results on noise supported signal propagation in arrays of coupled bistable elements. We present and compare experimental and numerical results for kink propagation under the influence of local and global fluctuations. As demonstrated previously for local noise, an optimum range of global noise power exists for which the medium acts as a reliable transmission ``channel''. We discuss implications for propagation failure in a model of cardiac tissue and present a general theo...

  5. Active noise cancellation algorithms for impulsive noise

    OpenAIRE

    Li, Peng; Yu, Xun

    2012-01-01

    Impulsive noise is an important challenge for the practical implementation of active noise control (ANC) systems. The advantages and disadvantages of popular filtered-X least mean square (FXLMS) ANC algorithm and nonlinear filtered-X least mean M-estimate (FXLMM) algorithm are discussed in this paper. A new modified FXLMM algorithm is also proposed to achieve better performance in controlling impulsive noise. Computer simulations and experiments are carried out for all three algorithms and th...

  6. The Detection and Exclusion of the Prostate Neuro-Vascular Bundle (NVB) in Automated HIFU Treatment Planning Using a Pulsed-Wave Doppler Ultrasound System

    Science.gov (United States)

    Chen, Wohsing; Carlson, Roy F.; Fedewa, Russell; Seip, Ralf; Sanghvi, Narendra T.; Dines, Kris A.; Pfile, Richard; Penna, Michael A.; Gardner, Thomas A.

    2005-03-01

    Men with prostate cancer are likely to develop impotence after prostate cancer therapy if the treatment damages the neuro-vascular bundles (NVB). The NVB are generally located at the periphery of the prostate gland. To preserve the NVB, a Doppler system is used to detect and localize the associated blood vessels. This information is used during the therapy planning procedure to avoid treatment surrounding the blood vessel areas. The Sonablate®500 (Focus Surgery, Inc.) image-guided HIFU device is enhanced with a pulse-wave multi-gate Doppler system that uses the current imaging transducer and mechanical scanner to acquire Doppler data. Doppler detection is executed after the regular B-mode images are acquired from the base to the apex of the prostate using parallel sector scans. The results are stored and rendered in 3-D display, registered with additional models generated for the capsule, urethra, and rectal wall, and the B-mode data and treatment plan itself. The display of the blood flow can be in 2-D color overlaid on the B-mode image or in 3-D color structure. Based on this 3-D model, the HIFU treatment planning can be executed in automated or manual mode by the physician to remove originally defined treatment zones that overlap with the NVB (for preservation of NVB). The results of the NVB detection in animal experiments, and the 3-D modeling and data registration of the prostate will be presented.

  7. Solar noise storms

    CERN Document Server

    Elgaroy, E O

    2013-01-01

    Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

  8. A study on transient enhancement for fault diagnosis based on an active noise control system

    OpenAIRE

    Tian, X.; Gu, Fengshou; Zhen, Dong; Tran, Tung; Ball, Andrew

    2012-01-01

    Active noise control (ANC) is a more effective technique used for acoustic noise cancelation in comparison with passive approaches which are difficult and expensive to implement, especially for cancelling the noise in the low frequency range. In the ANC system, an anti-noise signal is introduced to suppress the primary noise to produce a residual which is used for updating the adaptive filter coefficients. In this paper, a method of transient content enhancement for fault detection and diagno...

  9. NASA propeller noise research

    Science.gov (United States)

    Greene, G. C.

    1980-01-01

    The research in propeller noise prediction, noise/performance optimization, and interior reduction is described. Selected results are presented to illustrate the status of the technology and the direction of future research.

  10. Coupling Reduces Noise

    OpenAIRE

    Kia, Behnam; Kia, Sarvenaz; Lindner, John. F.; Sinha, Sudeshna; Ditto, William L.

    2014-01-01

    We demonstrate how coupling nonlinear dynamical systems can reduce the effects of noise. For simplicity we investigate noisy coupled map lattices. Noise from different lattice nodes can diffuse across the lattice and lower the noise level of individual nodes. We develop a theoretical model that explains this observed noise evolution and show how the coupled dynamics can naturally function as an averaging filter. Our numerical simulations are in excellent agreement with the model predictions.

  11. Nonlinear noise cancellation

    OpenAIRE

    Strauch, Paul E

    1997-01-01

    Noise or interference is often assumed to be a random process. Conventional linear filtering, control or prediction techniques are used to cancel or reduce the noise. However, some noise processes have been shown to be nonlinear and deterministic. These nonlinear deterministic noise processes appear to be random when analysed with second order statistics. As nonlinear processes are widespread in nature it may be beneficial to exploit the coherence of the nonlinear deterministic no...

  12. Noise in electromigrated nanojunctions

    OpenAIRE

    Wheeler, P. J.; Chen, Ruoyu; Natelson, D.

    2013-01-01

    Noise measurements are a probe beyond simple electronic transport that can reveal additional information about electronic correlations and inelastic processes. Here we report noise measurements in individual electromigrated nanojunctions, examining the evolution from the many channel regime to the tunneling regime, using a radio frequency technique. While we generally observe the dependence of noise on bias expected for shot noise, in approximately 12% of junction configurations we find discr...

  13. Noise and Neuronal Heterogeneity

    OpenAIRE

    Barber, Michael J.; Ristig, Manfred L.

    2010-01-01

    We consider signal transaction in a simple neuronal model featuring intrinsic noise. The presence of noise limits the precision of neural responses and impacts the quality of neural signal transduction. We assess the signal transduction quality in relation to the level of noise, and show it to be maximized by a non-zero level of noise, analogous to the stochastic resonance effect. The quality enhancement occurs for a finite range of stimuli to a single neuron; we show how to construct network...

  14. Noise in mesoscopic physics

    OpenAIRE

    Martin, Thierry

    2005-01-01

    This is a course on noise which covers some of the scattering theory for normal metals, Hanbury Brown and Twiss analogs for noise correlations with electrons, noise correlations in superconducting/normal metal junctions. Entanglement in such NS systems is described with a criterion for violating Bell inegalities. The last section is devoted to the perturbative derivation of noise in a particular one dimensional correlated electron system (Luttinger liquid): edge states in the fractional quant...

  15. Filtering Solid Gabor Noise

    OpenAIRE

    Lagae, Ares; Drettakis, George

    2011-01-01

    Solid noise is a fundamental tool in computer graphics. Surprisingly, no existing noise function supports both high-quality anti-aliasing and continuity across sharp edges. In this paper we show that a slicing approach is required to preserve continuity across sharp edges, and we present a new noise function that supports anisotropic filtering of sliced solid noise. This is made possible by individually filtering the slices of Gabor kernels, which requires the proper treatment of phase. This ...

  16. Adaptations, exaptations, and spandrels.

    Science.gov (United States)

    Buss, D M; Haselton, M G; Shackelford, T K; Bleske, A L; Wakefield, J C

    1998-05-01

    Adaptation and natural selection are central concepts in the emerging science of evolutionary psychology. Natural selection is the only known causal process capable of producing complex functional organic mechanisms. These adaptations, along with their incidental by-products and a residue of noise, comprise all forms of life. Recently, S. J. Gould (1991) proposed that exaptations and spandrels may be more important than adaptations for evolutionary psychology. These refer to features that did not originally arise for their current use but rather were co-opted for new purposes. He suggested that many important phenomena--such as art, language, commerce, and war--although evolutionary in origin, are incidental spandrels of the large human brain. The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. PMID:9612136

  17. Characteristics of USB noise

    Science.gov (United States)

    Gibson, J. S.; Searle, N.

    1976-01-01

    An extensive series of noise measurements, for a variety of geometric and operational parameters, was made on models of upper surface blowing (USB) powered lift systems. The data obtained were analyzed and the effects and trends of parametric variation defined. The behavior and nature of USB noise and the design of USB systems with low noise characteristics is examined.

  18. Noise at the Interface

    DEFF Research Database (Denmark)

    Prior, Andrew

    2011-01-01

    The notion of noise occupies a contested territory, in which it is framed as pollution and detritus even as it makes its opposite a possibility - noise is always defined in opposition to something else, even if this ‘other’ is not quite clear. This paper explores noise in the context of ‘the...

  19. [Assessment of noise exposure in sheep].

    Science.gov (United States)

    Hauser, R; Wechsler, B

    2013-02-01

    The behaviour of sheep was recorded as a reaction to the sound pressure levels caused by shooting with heavy machine guns. The reactions varied in intensity depending on the distance of the source of the noise from the fold. In the case of salvoes that were fired in the immediate vicinity of the fold and were associated with sound pressure levels higher than 120 dB (LCpeak), the sheep reacted with marked fright reactions, and no adaptation to the shooting noise was observed. It is concluded that the tolerable maximum noise level for sheep with this kind of noise source is likely to be less than 120 dB (LCpeak). PMID:23385071

  20. Core Noise - Increasing Importance

    Science.gov (United States)

    Hultgren, Lennart S.

    2011-01-01

    This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor

  1. Phylogenetic perspectives on noise-induced fear and annoyance

    Science.gov (United States)

    Bowles, Ann

    2003-04-01

    Negative human responses to noise are typically interpreted in terms of human psychological, cognitive, or social processes. However, it may be useful to frame hypotheses about human responses in terms of evolutionary history, during which negative responses have been part of a suite of adaptions to a variable sound environment. By comparing the responses of a range of nonhuman animals to various types of noise, it is possible to develop hypotheses about the ecology of human responses. Examples of noise-related phenomena that could be explained usefully from this perspective include the Schulz curve, noise-induced physical stress, acute fear responses induced by transient noise, and the relationship between temperament and noise-induced annoyance. Responses of animals from a range of taxa will be described and their behavior interpreted in terms of their life-history strategies. With this perspective, some testable hypotheses about noise-induced fear and annoyance will be suggested.

  2. Low-noise amplifier

    OpenAIRE

    V. B. Gulkov; A. S. Makarenko

    2012-01-01

    The mixture of signal and noise processing device is considered in this article. It contains two channels: the main channel (MC) contains the mixture of signal and noise, and compensation channel (CC) that extracts just a noise from the mixture. The feature of the processing circuit is that the mixture samples are formed by short impulses at the moments of passing signal through zero. Further antiphase noise is set in the channels, adder by which the noise is removed from mixture is set on th...

  3. Compression by Noise Equalization

    OpenAIRE

    Jähne, Bernd

    2013-01-01

    For any relation of the noise variance with the gray value, a nonlinear transform h(g) can be applied so that the variance of the transformed signal h is constant. The number of bits required to represent the noise-equalized signal is in good approximation equal to the maximum signal/noise ratio (SNRmax). Thus the noise-equalized signal of any imaging sensor with a full-well capacity of less than 2^16 can be represented by only 8 bit or less with only a slight increase in the overall noise le...

  4. Direct-reading dial for noise temperature and noise resistance

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1967-01-01

    An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance.......An attenuator arrangement for a noise generator is described. The scheme permits direct reading of both noise resistance and noise temperature¿the latter with a choice of source resistance....

  5. Low-noise amplifier

    Directory of Open Access Journals (Sweden)

    V. B. Gulkov

    2012-11-01

    Full Text Available The mixture of signal and noise processing device is considered in this article. It contains two channels: the main channel (MC contains the mixture of signal and noise, and compensation channel (CC that extracts just a noise from the mixture. The feature of the processing circuit is that the mixture samples are formed by short impulses at the moments of passing signal through zero. Further antiphase noise is set in the channels, adder by which the noise is removed from mixture is set on the cannels output. Study of the described device was carried out for simulated AM signal and white Gaussian noise in simulation environment Matlab. The results are shown, that device reduces noise by 16 dB of power.

  6. Nuclear Spin Noise and STM Noise Spectroscopy

    OpenAIRE

    Balatsky, A. V.; Fransson, J.; Mozyrsky, D.; Manassen, Yishay

    2006-01-01

    We consider fluctuations of the electronic spin due to coupling to nuclear spin. Noise spectroscopy of an electronic spin can be revealed in the Scanning Tunnelling Microscope (STM). We argue that the noise spectroscopy of electronic spin can reveal the nuclear spin dynamics due to hyperfine coupling. Tunnelling current develops satellites of the main lines at Larmor frequency and at zero frequency due to hyperfine coupling. We also address the role of the rf field that is at or near the reso...

  7. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  8. An Overview of the Adaptive Robust DFT

    Directory of Open Access Journals (Sweden)

    Djurović Igor

    2010-01-01

    Full Text Available Abstract This paper overviews basic principles and applications of the robust DFT (RDFT approach, which is used for robust processing of frequency-modulated (FM signals embedded in non-Gaussian heavy-tailed noise. In particular, we concentrate on the spectral analysis and filtering of signals corrupted by impulsive distortions using adaptive and nonadaptive robust estimators. Several adaptive estimators of location parameter are considered, and it is shown that their application is preferable with respect to non-adaptive counterparts. This fact is demonstrated by efficiency comparison of adaptive and nonadaptive RDFT methods for different noise environments.

  9. Urban Noise Protection

    Science.gov (United States)

    Jäcker-Cüppers, Michael

    Noise belongs to the severest environmental impairments in towns, with road traffic being the most annoying noise source. The reduction of these impairments and the precaution against new noise impacts is an important task of the communities. However, many of the potential abatement measures are not in the responsibility of the communities. In most European countries, noise emission regulations for road and rail vehicles and outdoor machinery are nowadays enforced by the European Union. Noise reception limits are generally enforced by national laws. Therefore, efficient noise abatement in towns has to be coordinated with the regional, national and supranational, i.e. European noise policy. The most important fields of action for the urban noise abatement are the roads, railways and airports with heavy traffic. For the avoidance of health risks due to noise here short-term reductions are needed, which can generally be achieved only by a combination of measures for which different stakeholders are responsible. This underlines the importance of integrated and coordinated noise abatement concepts.

  10. A Comparative Study of Removal Noise from Remote Sensing Image

    CERN Document Server

    Al-amri, Salem Saleh; Khamitkar, S D

    2010-01-01

    This paper attempts to undertake the study of three types of noise such as Salt and Pepper (SPN), Random variation Impulse Noise (RVIN), Speckle (SPKN). Different noise densities have been removed between 10% to 60% by using five types of filters as Mean Filter (MF), Adaptive Wiener Filter (AWF), Gaussian Filter (GF), Standard Median Filter (SMF) and Adaptive Median Filter (AMF). The same is applied to the Saturn remote sensing image and they are compared with one another. The comparative study is conducted with the help of Mean Square Errors (MSE) and Peak-Signal to Noise Ratio (PSNR). So as to choose the base method for removal of noise from remote sensing image.

  11. Perception Neural Networks for Active Noise Control Systems

    Directory of Open Access Journals (Sweden)

    Wang Xiaoli

    2012-11-01

    Full Text Available In a response to a growing demand for environments of 70dB or less noise levels, many industrial sectors have focused with some form of noise control system. Active noise control (ANC has proven to be the most effective technology. This paper mainly investigates application of neural network on self-adaptation system in active noise control (ANC. An active silencing control system is made which adopts a motional feedback loudspeaker as not a noise controlling source but a detecting sensor. The working fundamentals and the characteristics of the motional feedback loudspeaker are analyzed in detail. By analyzing each acoustical path, identification based adaptive linear neural network is built. This kind of identifying method can be achieved conveniently. The estimated result of each sound channel matches well with its real sound character, respectively.

  12. A Comparative Study of Removal Noise from Remote Sensing Image

    Directory of Open Access Journals (Sweden)

    Santosh Khamitkar

    2010-01-01

    Full Text Available This paper attempts to undertake the study of three types of noise such as Salt and Pepper (SPN, Random variation Impulse Noise (RVIN, Speckle (SPKN. Different noise densities have been removed between 10% to 60% by using five types of filters as Mean Filter (MF, Adaptive Wiener Filter (AWF, Gaussian Filter (GF, Standard Median Filter (SMF and Adaptive Median Filter (AMF. The same is applied to the Saturn remote sensing image and they are compared with one another. The comparative study is conducted with the help of Mean Square Errors (MSE and Peak-Signal to Noise Ratio (PSNR. So as to choose the base method for removal of noise from remote sensing image.

  13. Expectation-maximization (EM) Algorithm Based on IMM Filtering with Adaptive Noise Covariance%基于期望最大化算法的自适应噪声交互多模型滤波

    Institute of Scientific and Technical Information of China (English)

    雷明; 韩崇昭

    2006-01-01

    A novel method under the interactive multiple model (IMM) filtering framework is presented in this paper, in which the expectation-maximization (EM) algorithm is used to identify the process noise covariance Q online. For the existing IMM filtering theory, the matrix Q is determined by means of design experience, but Q is actually changed with the state of the maneuvering target.Meanwhile it is severely influenced by the environment around the target, i.e., it is a variable of time. Therefore, the experiential covariance Q can not represent the influence of state noise in the maneuvering process exactly. Firstly, it is assumed that the evolved state and the initial conditions of the system can be modeled by using Gaussian distribution, although the dynamic system is of a nonlinear measurement equation, and furthermore the EM algorithm based on IMM filtering with the Q identification online is proposed. Secondly, the truncated error analysis is performed. Finally,the Monte Carlo simulation results are given to show that the proposed algorithm outperforms the existing algorithms and the tracking precision for the maneuvering targets is improved efficiently.

  14. Radiation-force-based estimation of acoustic attenuation using harmonic motion imaging (HMI) in phantoms and in vitro livers before and after HIFU ablation

    Science.gov (United States)

    Chen, Jiangang; Hou, Gary Y.; Marquet, Fabrice; Han, Yang; Camarena, Francisco; Konofagou, Elisa

    2015-10-01

    Acoustic attenuation represents the energy loss of the propagating wave through biological tissues and plays a significant role in both therapeutic and diagnostic ultrasound applications. Estimation of acoustic attenuation remains challenging but critical for tissue characterization. In this study, an attenuation estimation approach was developed using the radiation-force-based method of harmonic motion imaging (HMI). 2D tissue displacement maps were acquired by moving the transducer in a raster-scan format. A linear regression model was applied on the logarithm of the HMI displacements at different depths in order to estimate the acoustic attenuation. Commercially available phantoms with known attenuations (n=5 ) and in vitro canine livers (n=3 ) were tested, as well as HIFU lesions in in vitro canine livers (n=5 ). Results demonstrated that attenuations obtained from the phantoms showed a good correlation ({{R}2}=0.976 ) with the independently obtained values reported by the manufacturer with an estimation error (compared to the values independently measured) varying within the range of 15-35%. The estimated attenuation in the in vitro canine livers was equal to 0.32   ±   0.03 dB cm-1 MHz-1, which is in good agreement with the existing literature. The attenuation in HIFU lesions was found to be higher (0.58   ±   0.06 dB cm-1 MHz-1) than that in normal tissues, also in agreement with the results from previous publications. Future potential applications of the proposed method include estimation of attenuation in pathological tissues before and after thermal ablation.

  15. Radiation-force-based estimation of acoustic attenuation using harmonic motion imaging (HMI) in phantoms and in vitro livers before and after HIFU ablation.

    Science.gov (United States)

    Chen, Jiangang; Hou, Gary Y; Marquet, Fabrice; Han, Yang; Camarena, Francisco; Konofagou, Elisa

    2015-10-01

    Acoustic attenuation represents the energy loss of the propagating wave through biological tissues and plays a significant role in both therapeutic and diagnostic ultrasound applications. Estimation of acoustic attenuation remains challenging but critical for tissue characterization. In this study, an attenuation estimation approach was developed using the radiation-force-based method of harmonic motion imaging (HMI). 2D tissue displacement maps were acquired by moving the transducer in a raster-scan format. A linear regression model was applied on the logarithm of the HMI displacements at different depths in order to estimate the acoustic attenuation. Commercially available phantoms with known attenuations (n = 5) and in vitro canine livers (n = 3) were tested, as well as HIFU lesions in in vitro canine livers (n = 5). Results demonstrated that attenuations obtained from the phantoms showed a good correlation (R² = 0.976) with the independently obtained values reported by the manufacturer with an estimation error (compared to the values independently measured) varying within the range of 15-35%. The estimated attenuation in the in vitro canine livers was equal to 0.32   ±   0.03 dB cm(-1) MHz(-1), which is in good agreement with the existing literature. The attenuation in HIFU lesions was found to be higher (0.58   ±   0.06 dB cm(-1) MHz(-1)) than that in normal tissues, also in agreement with the results from previous publications. Future potential applications of the proposed method include estimation of attenuation in pathological tissues before and after thermal ablation. PMID:26371501

  16. Mitigation of calorimeter noise.

    Energy Technology Data Exchange (ETDEWEB)

    Santi, P. A. (Peter A.); Bracken, D. S. (David S.); Smith, M. K. (Morag K.)

    2004-01-01

    One of the main factors that limit the sensitivity of calorimeters is the noise in the calorimeter response. A previous study into the sources of noise in a Wheatstone bridge calorimeter used by Department of Energy (DOE) facilities has shown that the control system for maintaining the water bath at a constant temperature was an important contributor to the noise in the system. In order to minimize the contribution that the control system makes to the noise in the calorimeter response, a new control system for the calorimeter has been developed. An experimental and analytical study has been performed to determine the effectiveness of this new control system in reducing the response noise in a Wheatstone bridge calorimeter. The results of this study are presented along with their implications for future work in minimizing the equilibrium noise of calorimeters.

  17. A normalized data-reusing least-mean-square algorithm of noise cancellation for magnetocardiography

    Institute of Scientific and Technical Information of China (English)

    Kong Xiang-Yan; Wang Hui-Wu; Tian Ye; Huang Xu-Guang; Zhang Li-Hua; Ren Yu-Feng; Chen Geng-Hua; Yang Qian-Sheng

    2004-01-01

    An adaptive filter based on Data-Reusing Least-Mean-Square algorithm has been proposed and applied in magnetocardiography (MCG) to suppress ambient noise. Numerical simulation studies indicate that the adaptive filter is a powerful noise suppresser for correlated interferences, especially for those with amplitude changing and time delay.Also the filter has a wide frequency bandwidth. With this filter, the signal-to-noise ratio of an MCG is improved to the intrinsic noise level. The periodic average method for further improvement of the noise level in MCG is also discussed.

  18. 聚焦超声波治疗女性外阴炎性疾病的疗效%The curative effect of HIFU on patients with vulvar intraepithelial nonneoplasia

    Institute of Scientific and Technical Information of China (English)

    提松梅; 韩燕; 尹格平

    2011-01-01

    Objective o investigate the curative effect of HIFU for no- specific vulvitis (simple pruritus of vulva. SPV) and vulvar intraepithelial nonneoplasia (VINN). Methods One hundred and forty- two patients with SPV, two hundred and sixth- seven patients with VINN ( 141 cases with lichen sclerosus of vulva and 126 cases with squamous hyperplasia of vulva. ) were treated by the HIFU programs. Results The overall effective rate was 90. 4% for SPV by two times of HIFU, 84. 8% for lichen sclerosus of vulva and 92. 0% for squamous hyperplasia of vulva by four times of HIFU therapy. The lesion area of VINN decreased from (14. 26±4. 79) cm2to (3. 83±2. 04) cm2 (P<0. 01). Conclusion HIFU is a simple, safe, effective and repeatable therapy method for SPV and VINN.%目的 探讨高强度聚焦超声治疗(HIFU)女性外阴炎性疾病(单纯外阴瘙痒症和外阴上皮内非瘤样病变)的疗效.方法 应用高强度超声治疗仪对142例单纯外阴瘙痒症、267例不同病理类型外阴上皮内非瘤样病变(141例硬化苔藓和126例鳞状上皮细胞增生),规范了对不同疾病的治疗方法以及疗效判别标准.结果 本方法对单纯外阴瘙痒症组两次治疗后总有效率为90.4%;对外阴上皮内非瘤样病变4次治疗后,病变区皮肤面积由(14.26±4.79)cm2减少至(3.83±2.04)cm2,差异有统计学意义(P<0.01),其中对硬化苔藓型明显有效率为94.8 0A,对鳞状上皮细胞增生型患者明显有效率为92.0%.结论 本组显示HIFU可使瘙痒症状显著减轻,外阴白色病变面积逐渐减少,并具有简便、无痛和安全无创等优点.

  19. MRI监控HIFU损伤活体兔肝VX2瘤的影像学观察%Imaging observation of MRI guided HIFU destroying rabbit liver VX2 tumor in vivo

    Institute of Scientific and Technical Information of China (English)

    沈洁

    2012-01-01

    目的 观察高强度聚焦超声(HIFU)损伤20例活体兔肝VX2瘤的磁共振成像(MRI)监控图像,探讨MRI图像变化及其与实际损伤的关系.方法 HIFU以点辐照的方式逐层覆盖20例活体兔肝VX2瘤,并在HFIU术前及术后即刻扫描快速自旋回波(TSE)序列T1加权像(T1WI)、T2WI及增强T1WI.观察MRI图像变化,并取瘤体组织作2,3,5-氯化三苯基四氮唑(TTC)染色及苏木素-伊红染色,进行病理检查.结果 MRI图像改变能较准确地反映HIFU术后即刻瘤体内部损伤情况.结论 MRI能有效监控及评价HIFU损伤活体兔肝VX2瘤的效果.%Objective To observe the magnetic resonance imaging(MRI) monitoring images of liver VX2 tumors which were destroyed by high intensity focused ultrasound(HIFU) in 20 rabbits in vivo and to explore the changes of MRI images and their relation to the actual damage. Methods HIFU irradiation covered liver VX2 tumors of 20 rabbits,layer by layer in way of focus point. T1-weighted image(T1WI) ,T2WI and enhanced T1WI of turbo spin-echo(TSE) sequence were performed before and instantly after HIFU treatment. Changes of MRI image were observed. Tumor tissue were taken for pathological examination using 2,3,5-tri-phenyl-2H-tetrazolium chloride(TTC) staining and hematoxylin-eosin staining. Results MRI images could accurately reflect the internal lesions in tumor immediately after HIFU treatment. Conclusion MRI can effectively monitor and evaluate the effects of HIFU on destroying rabbit liver VX2 tumor in vivo.

  20. Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU: Pilot Study in a Swine Model.

    Directory of Open Access Journals (Sweden)

    Merel Huisman

    Full Text Available Ultrasound (US-guided high intensity focused ultrasound (HIFU has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system.Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160-300 W. Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson's trichrome and toluidine blue staining.All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation.Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post

  1. Modified Adaptive Weighted Averaging Filtering Algorithm for Noisy Image Sequences

    Institute of Scientific and Technical Information of China (English)

    LI Weifeng; YU Daoyin; CHEN Xiaodong

    2007-01-01

    In order to avoid the influence of noise variance on the filtering performances, a modified adaptive weighted averaging (MAWA) filtering algorithm is proposed for noisy image sequences. Based upon adaptive weighted averaging pixel values in consecutive frames, this algorithm achieves the filtering goal by assigning smaller weights to the pixels with inappropriate estimated motion trajectory for noise. It only utilizes the intensity of pixels to suppress noise and accordingly is independent of noise variance. To evaluate the performance of the proposed filtering algorithm, its mean square error and percentage of preserved edge points were compared with those of traditional adaptive weighted averaging and non-adaptive mean filtering algorithms under different noise variances. Relevant results show that the MAWA filtering algorithm can preserve image structures and edges under motion after attenuating noise, and thus may be used in image sequence filtering.

  2. Word Identification in Noise

    OpenAIRE

    Pisoni, David B.

    1996-01-01

    Speech intelligibility has traditionally been measured by presenting words mixed in noise to listeners for identification at several different signal-to-noise ratios. The words are produced in isolation or in sentence contexts where the predictability of specific items can be varied. Psychometric functions are typically obtained relating signal-to-noise ratio to percent correct recognition. Error analyses are often carried out by examining response confusions to construct similarity spaces fo...

  3. Multidimensional Speckle Noise Model

    OpenAIRE

    Fàbregas Xavier; López-Martínez Carlos; Pottier Eric

    2005-01-01

    One of the main problems of SAR imagery is the presence of speckle noise, originated by the inherent coherent nature of this type of systems. For one-dimensional SAR systems it has been demonstrated that speckle can be considered as a multiplicative noise term. Nevertheless, this simple model cannot be exported when multidimensional SAR imagery is addressed. This paper is devoted to present the latest advances into the definition of a multidimensional speckle noise model which does not depen...

  4. Nuclear spin noise imaging

    OpenAIRE

    Müller, Norbert; Jerschow, Alexej

    2006-01-01

    NMR images were obtained from the proton spin noise signals of a water-containing phantom, which was placed in the highly tuned, low-noise resonant circuit of a cryogenically cooled NMR probe in the presence of systematically varied magnetic field gradients. The spatially resolved proton spin density was obtained from the raw signal by a modified projection–reconstruction protocol. Although spin noise imaging is inherently less sensitive than conventional magnetic resonance imaging, it afford...

  5. Aircrafts' taxi noise emission

    OpenAIRE

    Asensio Rivera, César; Pagán Muñoz, Raúl; López Navarro, Juan Manuel

    2008-01-01

    During planning stages, when noisy activity has not been implanted or while evaluating operation changes, it is necessary to find an environmental noise mapping prediction tool for future scenarios. When an activity is already implanted, it is possible to measure noise emissions, but this is expensive, so prediction tools can also be useful. Because of these reasons, for the last 10 years, as a response to the increasing concern for noise pollution in developed countries, several simulation m...

  6. Acceptable noise level

    DEFF Research Database (Denmark)

    Olsen, Steen Østergaard; Nielsen, Lars Holme; Lantz, Johannes;

    2012-01-01

    The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjec...... using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli....

  7. Traffic Noise Propagating from Vibration of Railway Wagon

    Directory of Open Access Journals (Sweden)

    Shao-Yi Hsia

    2013-01-01

    Full Text Available Traffic noise has become a serious environmental hazard as more cars are purchased and driven. To help objectively and subjectively reduce perceived noise load, methods to analyze traffic noise offer an important means of creating a design to reduce noise output from main sources and transmission routes. Acoustic analysis using BEASY and dynamic analysis using ANSYS are conducted to forecast noise at a distance of 15 m from a railway wagon travelling at 100 km/h. This noise is based on structural vibration only and it excludes other noise sources from the railway wagon. The simulation results demonstrate that the overall noise at 15 m from a railway wagon car is 85.1 dB(L from linear energy weighting calculation and 72.9 dB(A from the A-weighting calculation. In this study, noise level propagating from vibration of the railway wagon is measured or calculated using A-weighting filter to simulate the frequency response of the human ear. The study results can be useful to factories, companies, or organizations and can provide an important resource and help reduce traffic noise. This can be achieved by predetermining the test location and structure configuration and adapting local planning and thus preventing excessive traffic noise in residential areas.

  8. Partially informed noise traders

    OpenAIRE

    Aase, Knut K.; Bjuland, Terje; Øksendal, Bernt

    2012-01-01

    The single auction equilibrium of Kyle’s (1985) is studied, in which noise traders may be partially informed, or alternatively they can be manipulated. Unlike Kyle’s assumption that the quantity traded by the noise traders is independent of the asset value, we assume that the noise traders are able to correlate their trade with the true price. This has several implications for the equilibrium, one being that the informed trader’s expected profits decrease as the noise traders’ ability to corr...

  9. On 1/f Noise

    OpenAIRE

    Li, Ming; Zhao, Wei

    2012-01-01

    Due to the fact that 1/f noise gains the increasing interests in the field of biomedical signal processing and living systems, we present this introductive survey that may suffice to exhibit the elementary and the particularities of 1/f noise in comparison with conventional random functions. Three theorems are given for highlighting the particularities of 1/f noise. The first says that a random function with long-range dependence (LRD) is a 1/f noise. The secondindicates that a heavy-tailed r...

  10. Noise through Quantum Pumps

    OpenAIRE

    Polianski, M. L.; Vavilov, M. G.; Brouwer, P.W.

    2002-01-01

    We study the current noise through an unbiased quantum electron pump and its mesoscopic fluctuations for arbitrary temperatures and beyond the bilinear response. In the bilinear regime, we find the full distributions of the noise power and the current-to-noise ratio for a chaotic quantum dots with single-channel and many-channel ballistic point contacts. For a dot with many-channel point contacts we also calculate the ensemble-averaged noise at arbitrary temperature and pumping strength. In t...

  11. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  12. Detection and Cancellation of Jamming Signal Noise Using Digital Filters for Radar Applications

    OpenAIRE

    Ch. Anoosha; Ch. Kusmakumari; Nirmala, M.

    2013-01-01

    This paper considers the problem of detecting and classifying a radar target signal from a jamming signal produced from a target jammer source. Jamming is intentional emission of radio frequency signals to interfere with the operation of a radar by saturating its receiver with noise or false information. In order to distill the features of radar echo-signal affected by strong jamming noise, the adaptive filters are used to remove the noise and recover the radar echo-signal. An Adaptive filter...

  13. Desired Accuracy Estimation of Noise Function from ECG Signal by Fuzzy Approach

    OpenAIRE

    Vahabi, Zahra; Kermani, Saeed

    2012-01-01

    Unknown noise and artifacts present in medical signals with non-linear fuzzy filter will be estimated and then removed. An adaptive neuro-fuzzy interference system which has a non-linear structure presented for the noise function prediction by before Samples. This paper is about a neuro-fuzzy method to estimate unknown noise of Electrocardiogram signal. Adaptive neural combined with Fuzzy System to construct a fuzzy Predictor. For this system setting parameters such as the number of Membershi...

  14. Noise and Health: How does noise affect us?

    NARCIS (Netherlands)

    Miedema, H.M.E.

    2001-01-01

    Noise annoyance is a primary indication that noise is a problem, and by itself noise annoyance means that the quality of life is adversely affected. Results from noise annoyance research are presented that make possible a detailed evaluation of noise exposures with respect to the annoyance induced.

  15. Sounds and Noises. A Position Paper on Noise Pollution.

    Science.gov (United States)

    Chapman, Thomas L.

    This position paper focuses on noise pollution and the problems and solutions associated with this form of pollution. The paper is divided into the following five sections: Noise and the Ear, Noise Measurement, III Effects of Noise, Acoustics and Action, and Programs and Activities. The first section identifies noise and sound, the beginnings of…

  16. Adaptive wiener image restoration kernel

    Science.gov (United States)

    Yuan, Ding

    2007-06-05

    A method and device for restoration of electro-optical image data using an adaptive Wiener filter begins with constructing imaging system Optical Transfer Function, and the Fourier Transformations of the noise and the image. A spatial representation of the imaged object is restored by spatial convolution of the image using a Wiener restoration kernel.

  17. Adaptive Lighting

    OpenAIRE

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive LightingAdaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled i...

  18. MOWER ATTACHMENT NOISE

    OpenAIRE

    Mosdzianowski, G.

    1990-01-01

    The noise produced by grass mowing attachments fitted to small tractors and combining a number of rotary blades with a total cutting width of up to 120 cm was investigated. The paper develops a noise reduction concept based on an analysis of sound sources.

  19. Noise-induced linearisation

    OpenAIRE

    Dykman, Mark; Luchinsky, D. G.; Mannella, R.; McClintock, Peter V. E.; Short, H. E.; Stein, N. D.; Stocks, N. G.

    1994-01-01

    It is found that the response of a nonlinear dynamical system can be linearised, and its frequency dispersion diminished, by the addition of external noise of sufficient intensity. Taking as an example an overdamped bistable system driven by a low-frequency periodic field, this noise-induced linearisation is investigated through analogue electronic experiments. The wider implications are considered.

  20. Mediality is Noise

    DEFF Research Database (Denmark)

    Prior, Andrew

    This PhD is concerned with the use of noise as a material within media arts practice, especially in ‘post-digital’ contexts such as glitch electronica, glitch art and uses of old media. It examines the relationship between informational culture and noise, exploring the ways in which the structuring...

  1. Acceptable noise level

    DEFF Research Database (Denmark)

    Olsen, Steen Østergaard; Nielsen, Lars Holme; Lantz, Johannes;

    2012-01-01

    The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjects...

  2. Noise Pollution, Teachers' Edition.

    Science.gov (United States)

    O'Donnell, Patrick A.; Lavaroni, Charles W.

    One of three in a series about pollution, this teacher's guide for a unit on noise pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of noise pollution and involves students in processes of…

  3. EDA noise analysis

    International Nuclear Information System (INIS)

    Using orCAD Pspice EDA software, the circuit simulation and the analysis such as transient analysis, noise analysis, temperature analysis, are made for charge-sensitive preamplifier. By calculation and comparison, the result shows circuit noise responses according to the temperature changes. (authors)

  4. A Combined Feedback and Noise Cancellation Algorithm for Binaural Hearing Aids

    OpenAIRE

    Lee, H. -W.; JEON, M.-Y.

    2011-01-01

    This paper proposes an adaptive algorithm for the combined acoustic feedback and noise cancellation in the binaural hearing aids. The proposed algorithm is based on dual microphones for feedback cancellation and the beamforming method for noise cancellation. The coefficients of feedback canceller are updated after subtracting the speech signal from the input signal by dual microphones. And the noise canceller reduces the noise signal in the residual signal excluding the speech by the beam...

  5. A new similarity measure for nonlocal filtering in the presence of multiplicative noise

    OpenAIRE

    Teuber, Tanja; Lang, Annika

    2011-01-01

    This paper presents a new similarity measure and nonlocal filters for images corrupted by multiplicative noise. The considered filters are generalizations of the nonlocal means filter of Buades et al., which is known to be well suited for removing additive Gaussian noise. To adapt to different noise models, the patch comparison involved in this filter has first of all to be performed by a suitable noise dependent similarity measure. To this purpose, we start by studying a probabilistic measur...

  6. Low Complexity Expert Dependent Noise Filtration Algorithm

    Directory of Open Access Journals (Sweden)

    Sasi Rekha.Sanivarapu

    2012-06-01

    Full Text Available In this paper, a flexible and robust wavelet based image denoising algorithm is proposed, which adapts itself to various and unknown types of noise as well as to the preference of the medical expert: a single tuning parameter is used to balance the preservation of relevant details against the degree of noise reduction. We employ a preliminary coefficient classification technique to empirically estimate the statistical distributions of the coefficients that represent useful image features on the one hand and mainly noise on the other. The proposed algorithm is of low-complexity, both in its implementation and execution time. The results show that its usefulness for denoising and enhancement of the CT, Ultrasound and Magnetic Resonance images

  7. Speckle Noise Reduction in Medical Ultrasound Images

    Directory of Open Access Journals (Sweden)

    Faouzi Benzarti

    2012-03-01

    Full Text Available Ultrasound imaging is an incontestable vital tool for diagnosis, it provides in non-invasive manner the internal structure of the body to detect eventually diseases or abnormalities tissues. Unfortunately, the presence of speckle noise in these images affects edges and fine details which limit the contrast resolution and make diagnostic more difficult. In this paper, we propose a denoising approach which combines logarithmic transformation and a non linear diffusion tensor. Since speckle noise is multiplicative and nonwhite process, the logarithmic transformation is a reasonable choice to convert signal-dependent or pure multiplicative noise to an additive one. The key idea from using diffusion tensor is to adapt the flow diffusion towards the local orientation by applying anisotropic diffusion along the coherent structure direction of interesting features in the image. To illustrate the effective performance of our algorithm, we present some experimental results on synthetically and real echographic images.

  8. Active noise control technology. Active soon seigyo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, M.; Kokubo, F.; Tanaka, S.; Yao, K. (Sharp Corp., Osaka (Japan))

    1994-05-10

    The signal processing method of the Active Noise Control (ANC) system was studied. The principle of ANC is to output secondary sound waves having opposite phase, identical amplitude from the control point of the sound wave of the primary sound source, and eliminate the noise by interference. As application fields, there are air conditioner ducts and compressors as one dimensional noise source, and automobile and axial fan as three dimensional noise source. In order to improve the stability of coefficient renewal algorithm of Adaptive Digital Filter (ADF), for generation of opposite phase noise, DC-LMS algorithm which can control the rise in gain of specified frequency zone was proposed. Furthermore, with the purpose of reducing the amount of operation, the introduction of lattice type AR filter was tested for the stability of the filter in IIR-ADF (Infinite Impulse Response Adaptive Digital Filter) and its application process. The applicability studies of these improved methods on the noise inside of ducts were actually measured, and the effect was verified. For the multi-channel control of 3 dimensional noise source, reference scanning method to reduce the filter operation was proposed. In the partial space noise eliminating experiment, it was made clear that it possesses equivalent effect to error scanning method. 11 refs., 14 figs., 1 tab.

  9. Noise removal in nuclear medicine images by using multi resolution

    International Nuclear Information System (INIS)

    A novel flexible and dynamic algorithm for noise removal in nuclear medicine images is proposed. The images have a very low signal-to-noise ratio and the total number of registered photons is relatively small. The algorithm removes the noise from both the images original spatial domain and from the wavelet transform domain. In the spatial domain it uses both the autocorrelation technique in order to remove the noise that appears in a from of isolated pixels around the objects of interest and the information that each image contains about the signal in its neighbouring images. In the transform domain the wavelet coefficients filtration is carried out with a filter bank which meets the near-perfect reconstruction condition and is adapted to the signal. In addition, the coefficients that correspond to noise and are about to be discarded are selected by using a non uniform threshold which is adapted to the spatial varying noise level. Criteria for selection of an optimal decomposition level for the NM images are defined. In order to suppress the noise, multi resolution characteristics of both the signal and noise are used.(Author)

  10. Substation noise screening tool

    Energy Technology Data Exchange (ETDEWEB)

    Maybee, Nigel; Everton, Pascal [HFP Acoustical Consultants Corp. (Canada)], email: nigel.maybee@hfpacoustical.com; Chow, Vincent [Altalink Management Ltd. (Canada)], email: Vincent.Chow@AltaLink.ca

    2011-07-01

    Alberta noise regulations require energy-related facilities to conduct predictions on sound levels, especially for large and medium noise sources. This is usually done with well-known modelling software, but that can be disadvantageous when assessing the noise impact of smaller noise sources, such as transformer substations. This paper focuses on the development of a spreadsheet substation noise screening tool to assess the noise impact of a small transformer substation with precision and ease-of-use. Three aspects must be considered: transformer sound levels, which can be provided by the manufacturer or extracted from accepted sound level references; sound power calculations, which depend on the substation size and operating regime; and sound propagation calculations, which take into account the distance of the receptor from the substation and sound absorption by the air and ground. Comparison of results obtained with this tool with results generated by standard sound modelling software shows the utility, accuracy and ease-of-use of this screening method for assessing the noise impact of transformer substations.

  11. Noise and Hearing Loss Prevention

    Science.gov (United States)

    ... Follow us on Twitter Noise Manufacturing Construction SafeInSound Noise and Hearing Loss on the NIOSH Science Blog ... Topics Publications and Products Programs Contact NIOSH NIOSH NOISE AND HEARING LOSS PREVENTION Recommend on Facebook Tweet ...

  12. Noise: sound reactive fashion

    OpenAIRE

    Paiva, André; Catarino, André P.; Cabral, Isabel; Carvalho, Helder

    2015-01-01

    Sound and noise have an important influence in our daily lives. They can positively or negatively change our quality of life. Given the idea that it is harder to ignore what we see, rather than what we hear, the team developed a garment that senses environmental noise and shows it through lighting, to make people aware of the noise around them. The garment chosen was a jacket, with a deliberately provocative design. It is the authors’ intention to study the integration of lighting in garments...

  13. Noise blind test

    OpenAIRE

    H. Cadet

    2006-01-01

    In the aim of characterizing site condition for seismic risk, the microtremor or ambient noise studies have been developed. The main objective of this blind test is to check of the reliability of results, to observe the user subjectivity (array choice, parameters that are user depend) in the noise recordings analyze. Noise records were analysed on single-station with H/V method and with several sensors for array method to determine the dispersion characteristics of the surface-wave part of th...

  14. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.

    2015-08-19

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  15. Hypermedicalization in White Noise.

    Science.gov (United States)

    Benson, Josef

    2015-09-01

    The Nazis hijacked Germany's medical establishment and appropriated medical language to hegemonize their ideology. In White Noise, shifting medical information stifles the public into docility. In Nazi Germany the primacy of language and medical authority magnified the importance of academic doctors. The muddling of identities caused complex insecurities and the need for psychological doubles. In White Noise, Professor Gladney is driven by professional insecurities to enact a double in Murray. Through the manipulation of language and medical overreach the U.S., exemplified in the novel White Noise, has become a hypermedicalized society where the spirit of the Hippocratic Oath has eroded. PMID:24458659

  16. Quantum phase slip noise

    Science.gov (United States)

    Semenov, Andrew G.; Zaikin, Andrei D.

    2016-07-01

    Quantum phase slips (QPSs) generate voltage fluctuations in superconducting nanowires. Employing the Keldysh technique and making use of the phase-charge duality arguments, we develop a theory of QPS-induced voltage noise in such nanowires. We demonstrate that quantum tunneling of the magnetic flux quanta across the wire yields quantum shot noise which obeys Poisson statistics and is characterized by a power-law dependence of its spectrum SΩ on the external bias. In long wires, SΩ decreases with increasing frequency Ω and vanishes beyond a threshold value of Ω at T →0 . The quantum coherent nature of QPS noise yields nonmonotonous dependence of SΩ on T at small Ω .

  17. Photon shot noise

    OpenAIRE

    Beenakker, C. W. J.; Patra, M.

    1999-01-01

    A recent theory is reviewed for the shot noise of coherent radiation propagating through a random medium. The Fano factor P/I (the ratio of the noise power and the mean transmitted current) is related to the scattering matrix of the medium. This is the optical analogue of Buttiker's formula for electronic shot noise. Scattering by itself has no effect on the Fano factor, which remains equal to 1 (as for a Poisson process). Absorption and amplification both increase the Fano factor above the P...

  18. Potential of neuro-fuzzy methodology to estimate noise level of wind turbines

    Science.gov (United States)

    Nikolić, Vlastimir; Petković, Dalibor; Por, Lip Yee; Shamshirband, Shahaboddin; Zamani, Mazdak; Ćojbašić, Žarko; Motamedi, Shervin

    2016-01-01

    Wind turbines noise effect became large problem because of increasing of wind farms numbers since renewable energy becomes the most influential energy sources. However, wind turbine noise generation and propagation is not understandable in all aspects. Mechanical noise of wind turbines can be ignored since aerodynamic noise of wind turbine blades is the main source of the noise generation. Numerical simulations of the noise effects of the wind turbine can be very challenging task. Therefore in this article soft computing method is used to evaluate noise level of wind turbines. The main goal of the study is to estimate wind turbine noise in regard of wind speed at different heights and for different sound frequency. Adaptive neuro-fuzzy inference system (ANFIS) is used to estimate the wind turbine noise levels.

  19. Adaptive Endpoint Detection Based on Subband Speech

    Institute of Scientific and Technical Information of China (English)

    张文军; 谢剑英

    2003-01-01

    An adaptive endpoint detection algorithm based on band energy and adaptive smoothing algorithm is described.This algorithm utilizes the capability of adaptive smoothing algorithm that intensifies the discontinuity between local areas. The band energy features are selected because of their usefulness in detecting high energy regions (in the incoming signal) and making the distinction between speech and noise. Heuristic "edge-focusing" is used to endpoint detection to save the time in iteration.

  20. Adaptive Filter in SAR Interferometry Derived DEM

    Institute of Scientific and Technical Information of China (English)

    XU Caijun; WANG Hua; WANG Jianglin; GE Linlin

    2005-01-01

    In this paper, the performance of median filter, elevation dependent adaptive sigma median filter, and directionally dependent adaptive sigma median filter are tested on both InSAR Tandem DEM and simulated high-level noisy DEM. Through the comparison, the directionally dependent adaptive sigma median filter is proved to be the most effective one not only in the noise removing but also in the boundary preserve.

  1. Noise upon the Sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity’s (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...... samplerate of the shimmer and jitter. A harmonic model introduces individual and common irregularity, and adds a correlation control. The model has been implemented in max/msp and used in contemporary music compositions....

  2. Noise upon the sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other Sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity's (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...... samplerate of the shimmer and jitter. A harmonic model introduces individual and common irregularity, and adds a correlation control. The model has been implemented in max/msp and used in contemporary Music compositions....

  3. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  4. Geometry And Quantum Noise

    CERN Document Server

    Barbon, Jose L F

    2014-01-01

    We study the fine structure of long-time quantum noise in correlation functions of AdS/CFT systems. Under standard assumptions of quantum chaos for the dynamics and the observables, we estimate the size of exponentially small oscillations and trace them back to geometrical features of the bulk system. The noise level is highly suppressed by the amount of dynamical chaos and the amount of quantum impurity in the states. This implies that, despite their missing on the details of Poincare recurrences, `virtual' thermal AdS phases do control the overall noise amplitude even at high temperatures where the thermal ensemble is dominated by large AdS black holes. We also study EPR correlations and find that, in contrast to the behavior of large correlation peaks, their noise level is the same in TFD states and in more general highly entangled states.

  5. Occupational Noise Exposure

    Science.gov (United States)

    ... the ear drum and are transmitted to the middle and inner ear. In the middle ear three small bones called the malleus (or ... quiet area). Restricting worker presence to a suitable distance away from noisy equipment. Controlling noise exposure through ...

  6. Noise and Neuronal Heterogeneity

    CERN Document Server

    Barber, Michael J

    2010-01-01

    We consider signal transaction in a simple neuronal model featuring intrinsic noise. The presence of noise limits the precision of neural responses and impacts the quality of neural signal transduction. We assess the signal transduction quality in relation to the level of noise, and show it to be maximized by a non-zero level of noise, analogous to the stochastic resonance effect. The quality enhancement occurs for a finite range of stimuli to a single neuron; we show how to construct networks of neurons that extend the range. The range increases more rapidly with network size when we make use of heterogeneous populations of neurons with a variety of thresholds, rather than homogeneous populations of neurons all with the same threshold. The limited precision of neural responses thus can have a direct effect on the optimal network structure, with diverse functional properties of the constituent neurons supporting an economical information processing strategy that reduces the metabolic costs of handling a broad...

  7. Adaptive antennas and receivers

    CERN Document Server

    Weiner, Melvin M

    2005-01-01

    In our modern age of remote sensing, wireless communication, and the nearly endless list of other antenna-based applications, complex problems require increasingly sophisticated solutions. Conventional antenna systems are no longer suited to high-noise or low-signal applications such as intrusion detection. Detailing highly effective approaches to non-Gaussian weak signal detection, Adaptive Antennas and Receivers provides an authoritative introduction to state-of-the-art research on the modeling, testing, and application of these technologies.Edited by innovative researcher and eminent expert

  8. Experimental investigation of MRgHIFU sonication with interleaved electronic and mechanical displacement of the focal point for transrectal prostate application

    Science.gov (United States)

    Petrusca, Lorena; Ngo, Jacqueline; Brasset, Lucie; Blanc, Emmanuel; Murillo, Adriana; Auboiroux, Vincent; Cotton, François; Chapelon, Jean-Yves; Salomir, Rares

    2012-08-01

    High intensity focused ultrasound (HIFU) under MRI guidance may provide minimally invasive treatment for localized prostate cancer. In this study, ex vivo and in vivo experiments were performed using a prostate-dedicated endorectal phased array (16 circular elements arranged on a truncated spherical cap of radius 60 mm) and a translation-rotation mechanical actuator in order to evaluate the lesion formation and the potential interest of dual-modality (electronic and mechanical) interleaved displacement of the focus for volumetric sonication paradigms. Different sonication sequences, including elementary lesions, line scan, slice sweeping and volume sonications, were investigated with a clinical 1.5 T MR scanner. Two orthogonal planes (axial and sagittal) were simultaneously monitored using rapid MR thermometry (PRFS method) and the temperature and thermal dose maps were displayed in real time. No RF interferences were detected in MR acquisition during sonications. The shape of the thermal lesions in vivo was examined at day 5 post-treatment by MRI follow-up (T2w sequence and Gd-T1w-TFE) and postmortem histological analysis. This study suggests that electronic displacement of the focus (along the ultrasound propagation axis) interleaved with mechanical X-Z translations and rotation around B0 can be a suitable modality to treat patient-specific sizes and shapes of a pathologic tissue. The electronic displacement of focus (achieved in less than 0.1 s) is an order of magnitude faster than the mechanical motion of the HIFU device (1 s latency). As an example, for an in vivo volumetric sonication with foci between 32 and 47 mm (7 successive line scans, 11 lines/slice, 4 foci/line) with applied powers between 17.4 and 39.1 Wac, a total duration of sonication of 408.1 s was required to ablate a volume of approximately 5.7 cm3 (semi-chronic lesion measured at day 5), while the maximum temperature elevation reached was 30 °C. While electronic focusing is necessary to speed

  9. Noise Secured Internet

    OpenAIRE

    Barbosa, Geraldo A.

    2005-01-01

    This work shows how a secure Internet can be implemented through a fast key distribution system that uses physical noise to protect the transmitted information. Starting from a shared random sequence $K_0$ between two (or more) users, longsequences $R$ of random bits can be shared. The signals sent over the Internet are deterministic but have a built-in Nature-made uncertainty that protects the shared sequences. After privacy amplification the shared $R$ random bits --encrypted by noise-- are...

  10. Nonequilibrium spin noise spectroscopy

    OpenAIRE

    Li, Fuxiang; Pershin, Yuriy V.; Slipko, Valeriy A.; Sinitsyn, Nikolai A.

    2013-01-01

    Spin Noise Spectroscopy (SNS) is an experimental approach to obtain correlators of mesoscopic spin fluctuations in time by purely optical means. We explore the information that this technique can provide when it is applied to a weakly non-equilibrium regime when an electric current is driven through a sample by an electric field. We find that the noise power spectrum of conducting electrons experiences a shift, which is proportional to the strength of the spin-orbit coupling for electrons mov...

  11. Noise in Biology

    OpenAIRE

    Tsimring, Lev S

    2014-01-01

    Noise permeates biology on all levels, from the most basic molecular, sub-cellular processes to the dynamics of tissues, organs, organisms, and populations. The functional roles of noise in biological processes can vary greatly. Along with standard, entropy-increasing effects of producing random mutations, diversifying phenotypes in isogenic populations, limiting information capacity of signaling relays, it occasionally plays more surprising constructive roles by accelerating the pace of evol...

  12. Gravitational Wave Confusion Noise

    OpenAIRE

    Cornish, Neil J.

    2003-01-01

    One of the greatest challenges facing gravitational wave astronomy in the low frequency band is the confusion noise generated by the vast numbers of unresolved galactic and extra galactic binary systems. Estimates of the binary confusion noise suffer from several sources of astrophysical uncertainty, such as the form of the initial mass function and the star formation rate. There is also considerable uncertainty about what defines the confusion limit. Various ad-hoc rules have been proposed, ...

  13. ENDOGENOUS NOISE TRADERS

    OpenAIRE

    Salomonsson, Marcus

    2006-01-01

    We construct a parsimonious model of a financial market where the marginal investor is an endogenous noise trader. Such a trader anticipates that future shocks may force him to exit his position. In compensation he requires a higher return. We show that the original seller of the asset pays the required return. This can only be optimal if the seller has access to an investment opportunity that gives a sufficiently high return, compared to the noise trader's investment opportunities. We also s...

  14. Noise Stabilized Random Attractor

    OpenAIRE

    Finn, J.M.; Tracy, E. R.; Cooke, W. E.; Richardson, A. S.

    2005-01-01

    A two dimensional flow model is introduced with deterministic behavior consisting of bursts which become successively larger, with longer interburst time intervals between them. The system is symmetric in one variable x and there are bursts on either side of x = 0, separated by the presence of an invariant manifold at x = 0. In the presence of arbitrarily small additive noise in the x direction, the successive bursts have bounded amplitudes and interburst intervals. This system with noise is ...

  15. Active road noise reduction

    OpenAIRE

    Vraničar, Primož

    2012-01-01

    Theoretical principle of noise cancellation can be realized in the ideal studio conditions, but when the experiment is put into actual space and realized, we can see that the sound only partly cancels itself, on some frequencies more and on some less. However, in construction engineering we are not only dealing with certain frequencies but with frequency spectrums, if not with the whole frequency field. It is relatively hard to control the noise in traffic. We are dealing with a larger freque...

  16. Gas plant environmental noise

    International Nuclear Information System (INIS)

    In September 1988, the Energy Resources Conservation Board which regulates the Alberta oil and gas industry tightened its environmental noise guidelines by a factor of 10. New nighttime maximum permissible noise levels as low as 40 dBA are now enforceable in rural areas. The directive is retroactively applicable upon residential complaints and necessitated the use of radical innovations for industry to comply. Details are presented of noise and noise parameters, acoustic fields, dissipation, absorption and diffraction. Major sources of gas plant noise are engine and turbine exhausts, air coolers and cooling towers, purge blowers for electric motors, piping and valves, and flares. Attenuation techniques include silencers, berms and dykes, acoustic lagging and housing, variable speed drives, and stack induced air draft cooler. Recommendations for noise abatement include: house all rotating equipment in acoustically lined buildings; muffle engine exhausts and purge blower vents with reactive silencers where possible; choose electric over engine driven equipment; keep a good mix of engine speeds, fan speeds, and blade counts to reduce tonal spikes; don't rely on berms or dykes; choose water cooling towers over aerial coolers and fit aerial coolers with variable speed drive fans; experiment with stack induced draft coolers where water cooling is not an option; and use process speed valves where possible over bypass valving. 18 figs

  17. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

    Active noise control - the reduction of noise by generating an acoustic signal that actively interferes with the noise - has become an active area of basic research and engineering applications. The aim of this book is to present all of the basic knowledge one needs for assessing how useful active noise control will be for a given problem and then to provide some guidance for designing, setting up, and tuning an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the book is short and descriptive. It leaves for more advanced texts or research monographs all mathematical details and proofs concerning vibrations, signal processing and the like. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include: basic acoustics; human perception and sound; sound intensity...

  18. Low-rank Matrix Factorization under General Mixture Noise Distributions

    OpenAIRE

    Cao, Xiangyong; Zhao, Qian; Meng, Deyu; Chen, Yang; Xu, Zongben

    2016-01-01

    Many computer vision problems can be posed as learning a low-dimensional subspace from high dimensional data. The low rank matrix factorization (LRMF) represents a commonly utilized subspace learning strategy. Most of the current LRMF techniques are constructed on the optimization problems using L1-norm and L2-norm losses, which mainly deal with Laplacian and Gaussian noises, respectively. To make LRMF capable of adapting more complex noise, this paper proposes a new LRMF model by assuming no...

  19. CMOS image sensor noise reduction method for image signal processor in digital cameras and camera phones

    Science.gov (United States)

    Yoo, Youngjin; Lee, SeongDeok; Choe, Wonhee; Kim, Chang-Yong

    2007-02-01

    Digital images captured from CMOS image sensors suffer Gaussian noise and impulsive noise. To efficiently reduce the noise in Image Signal Processor (ISP), we analyze noise feature for imaging pipeline of ISP where noise reduction algorithm is performed. The Gaussian noise reduction and impulsive noise reduction method are proposed for proper ISP implementation in Bayer domain. The proposed method takes advantage of the analyzed noise feature to calculate noise reduction filter coefficients. Thus, noise is adaptively reduced according to the scene environment. Since noise is amplified and characteristic of noise varies while the image sensor signal undergoes several image processing steps, it is better to remove noise in earlier stage on imaging pipeline of ISP. Thus, noise reduction is carried out in Bayer domain on imaging pipeline of ISP. The method is tested on imaging pipeline of ISP and images captured from Samsung 2M CMOS image sensor test module. The experimental results show that the proposed method removes noise while effectively preserves edges.

  20. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... distributed differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial...

  1. Noise composed of multiplication of two dichotomous noises

    Institute of Scientific and Technical Information of China (English)

    Li Jing-Hui

    2008-01-01

    In this paper, we introduce a noise which is composed of multiplication of two dichotomous noises, and derive the probability density and the statistical properties of this noise. The obtained results can help study the resonant activation phenomenon, the phenomenon of stochastic resonance, the transport of particles, and the nonequilibrium (phase) transition for the systems driven by this noise.

  2. Noise pollution from wind turbine gears loudness of structural noise sources related to gears

    International Nuclear Information System (INIS)

    The purpose of the project has been to develop a method for determination of the structure-borne noise source strength of the gearbox in a typical modern Danish wind turbine construction, with special reference to the tonal noise emission form the turbines. Through study and evaluation of eight potential methods, a simple method has ben formulated. The method is based on measurements of the free vibration velocity level on the gearbox in a load test bed. The relation between this source strength measure and the gearbox related noise from wind turbines has been documented by measurements made during the project together with earlier measurements. The method is intended as a tool for the wind turbine manufacturer, for control of the gearbox related noise from the wind turbines, due to structure-borne noise from the gearbox. It may be used for preparation of specifications to the gearbox manufacturer on test procedure and acceptable source strength levels. Also, it may be used for evaluation of the transmission and radiation of gearbox related noise, for example in order to uncover weaknesses in a prototype turbine. Suggestions for adaptation and evolution of the method has been given, thereby improving the strength of the method for the individual wind turbine manufacturer. (au) 19 refs

  3. An Adaptive Unscented Kalman Filtering Algorithm for MEMS/GPS Integrated Navigation Systems

    OpenAIRE

    Jianhua Cheng; Daidai Chen; Rene Jr. Landry; Lin Zhao; Dongxue Guan

    2014-01-01

    MEMS/GPS integrated navigation system has been widely used for land-vehicle navigation. This system exhibits large errors because of its nonlinear model and uncertain noise statistic characteristics. Based on the principles of the adaptive Kalman filtering (AKF) and unscented Kalman filtering (AUKF) algorithms, an adaptive unscented Kalman filtering (AUKF) algorithm is proposed. By using noise statistic estimator, the uncertain noise characteristics could be online estimated to adaptively com...

  4. Aircraft noise - Different ways to monitor the noise load

    Science.gov (United States)

    Bekebrede, G.

    Measures taken by the Dutch government to reduce aircraft-noise disturbances including the establishment of noise zones in which subsequent building is forbidden, while already existing homes are provided with noise insulation are discussed. To ensure accurate noise monitoring, the following recommendations were made by the NLR: (1) regular noise load calculations, utilizing aircraft noise and performance data, the air traffic mix, and flight route information; (2) flight track monitoring, performed by a computerized Flight Track and Aircraft Noise Monitoring System which identifies all aircraft deviating from the prescribed track (i.e., flying over congested regions); and (3) actual noise monitoring, to guard the noise level at a specific noise-sensitive area in close proximity to the airfield, such as a hospital.

  5. Research of Anti-Noise Image Salient Region Extraction Method

    Directory of Open Access Journals (Sweden)

    Bing XU

    2014-01-01

    Full Text Available The existing image salient region extraction technology is mostly suitable for processing noise-free images, and there is a lack of studies on the impact of noise on images. In this study the adaptive kernel function was employed in image salient region detection. The salient property of a region was determined by the dissimilarities between the pixels of the image region and its surroundings. The dissimilarity was measured as a decreasing function associated with adaptive kernel regression. The proposed algorithm used multi-scale fusion method to obtain the salient region of the whole image. As adaptive kernel function has strong anti-noise characteristics, the proposed algorithm was characterized with the same robustness. A numerical simulation experiment was conducted on salient region extraction of images with noise and without noise. A comparison between this study’s results and two existing salient region extraction methods revealed that the proposed method in this study was superior in its extraction accuracy of image salient regions and could reduce interference of image noise.

  6. Light weight polarized polypropylene foam for noise shielding

    Science.gov (United States)

    Zelfer, Travis J.; Warne, Derik S.; Korde, Umesh A.

    2009-03-01

    The high levels of noise generated during launch can destroy sensitive equipment on space craft. Passive damping systems, like acoustic blankets, work to reduce the high frequency noise but do little to the low frequency noise (foams with high piezoelectric coupling constants are being used as new types of actuators and sensors. Further impedance control through the inverse piezoelectric effect will lead to a new "semi-active" approach that will reduce low frequency noise levels. Combining layers of conventional nonpiezoelectric foam and ferroelectret materials with a multiple loop feedback system will give a total damping effect that is adaptable over a wide band of low frequencies. This paper covers the manufacturing methods that were used to make polarized polypropylene foam, to test the foam for its polarized response and its noise shielding ability.

  7. Novel effect of interplay of internal and external noise on the dynamics of calcium oscillations

    International Nuclear Information System (INIS)

    Graphical abstract: When the external noise is small (D ≤ 0.8), R goes through a maximum at an optimal system size V, indicating the occurring of internal-noise stochastic resonance (INSR), and the curves become higher with the increases of D, which shows that INSR can be enhanced by the external noise in a certain range of external noise intensity ((D ≤ 0.8). If D > 0.8, R monotonically increases and the peak disappears. When D increases further, the R curve becomes lower. Research highlights: → External noise coherence resonance (ENCR) can be suppressed by internal noise. → Internal noise stochastic resonance (INSR) can be enhanced by external noise. → When INSR occurs, the optimal system size can be regulated by the external noise. - Abstract: Using a mesoscopic stochastic model, the effect of interplay of external and internal noise on the dynamics of calcium oscillations was studied. When the system was tuned near a Hopf bifurcation point and driven by external noise or internal noise only, the existence of external noise coherence resonance (ENCR) or internal-noise stochastic resonance (INSR) was found, respectively. When both of the noises were considered, it was found that ENCR could be suppressed by internal noise, while INSR could be enhanced by external noise in a certain range of external noise intensity. It was also interesting to note that the optimal system size can be regulated by the external noise when the INSR occurs. The cell system may adapt to adjust the optimal size according to the external noise, indicating some kind of self-tuning mechanism involved in stochastic calcium dynamics.

  8. Noise Control and Noise Evaluation in Aircraft Engines

    OpenAIRE

    石井, 達哉; Ishii, Tatsuya

    2002-01-01

    Aircraft engine noise emitted for example by the jet exhaust, fan, compressor, turbine and combustor is the predominant factor in total aircraft noise during take-off and landing. As a result of enormous efforts to alleviate engine noise, noise levels have been improved by more than 20 dB compared to the first generation of airliners. However, the growing volume of air transport means that further noise reduction is still required. With this background, we decided to concentrate on two techni...

  9. Does Masking Matter? Shipping Noise and Fish Vocalizations.

    Science.gov (United States)

    Neenan, Sarah T V; Piper, Rayner; White, Paul R; Kemp, Paul; Leighton, Timothy G; Shaw, Peter J

    2016-01-01

    Shipping creates large near-field background noises at levels similar to or higher than fish vocalizations and in the same critical bandwidths. This noise has the potential to "mask" biologically important signals and prevent fish from hearing them; any interference with the detection and recognition of sounds may impact fish survival. The Lombard effect, whereby vocalizations are altered to reduce or exclude masking effects, is an adaptation that has been observed in mammals and birds. Research is needed to establish whether the Lombard effect occurs in fish to gain a better understanding of the implications of noise pollution on fish populations. PMID:26611028

  10. Reducing environmental noise impacts: A USAREUR noise management program handbook

    Science.gov (United States)

    Feather, Timothy D.; Shekell, Ted K.

    1991-06-01

    Noise pollution is a major environmental problem faced by the U.S. Army in Europe. Noise-related complaints from German citizens can escalate into intense political issues in German communities. This in turn hampers efficient operation of military training and often times threatens the Army's mission. In order to remedy these problems, USAREUR has developed a noise management program. A successful noise management program will limit the impact of unavoidable noise on the populace. This report, a component of the noise management program, is a reference document for noise management planning. It contains guidelines and rules-of-thumb for noise management. This document contains procedures which operation and training level personnel can understand and apply in their day to day noise management planning. Noise mitigation tips are given. Basic technical information that will aid in understanding noise mitigation is provided along with noise management through land use planning. Noise management for specific components of the military community, (airfields, base operations, training areas, and housing and recreation areas) are addressed. The nature of noise generated, means of noise abatement at the source, path, and receiver (both physical and organizational/public relations methods), and a case study example are described.

  11. A Review of Decision Based Impulse Noise Removing Algorithms

    Directory of Open Access Journals (Sweden)

    SnehalAmbulkar

    2014-04-01

    Full Text Available Noises is an unwanted factor in digital image and videos, hiding the details and destroying image information. Hence denoising has great importance to restore the details and to improve the quality measures. This paper takes a look towards different type of noise found in digital images, Denoising domains, and classification of denoising filters. Some denoising filters like Median filter (MF, Adaptive median filter (AMF and simple adaptive median filters (SAMF are described and compared briefly. A new approach is proposed for video denoising using combination of median filters with multiple views.

  12. Can TRUS Power Doppler Predict the Preservation of Erectile Function in HIFU Treatment of Localised Prostate Cancer? — A Preliminary Study

    Science.gov (United States)

    Hoh, I. M.; Calleary, J. G.; Moore, C.; Emberton, M.; Allen, C.

    2006-05-01

    Perhaps the single most significant unifying feature in men diagnosed with organ confined prostate cancer is the hope of erectile preservation in the treatment that offers cure. Although it is not 100% certain that the preservation of neurovascular bundle (NVB) can actually lead to intact sexual function, there is evidence that non-sparing nerve radical prostatectomy has a much higher incidence of impotence compared to nerve-sparing ones. The idea to monitor NVB flow can be realized using a simple power Doppler technique that was done before and after HIFU. The NVB flow was found intact in all patients (n=14). Tumescence returned in 93% of patients with a mean time of 6 weeks for this to occur. The erectile function score, IIEF-15 decreased by a third but shows a trend towards recovery. This preliminary study demonstrates the feasibility of transrectal power Doppler as a monitoring tool to provide immediate feedback on the NVB flow which was found intact in all patients. Although early reports of the tumescence proved encouraging, its full impact on erectile function will require longer follow-up.

  13. High-intensity focused ultrasound (HIFU) using Sonablate{trade mark, serif} devices for the treatment of localized prostate cancer: 13-year experience

    Science.gov (United States)

    Uchida, Toyoaki; Tomonaga, Tetsuro; Shoji, Sunao; Kim, Hakushi; Nagata, Yoshihiro

    2012-11-01

    To report on the long-term results of high-intensity focused ultrasound (HIFU) in the treatment of localized prostate cancer. Eight hundred and eighty-four men with prostate cancer treated with Sonablate® (SB) devices were included. All patients were followed for more than 2 years. The patients were divided into three groups: in the first group, 419 patients were treated with SB200/500 from 1999 to 2006; in the second group, 263 patients were treated with SB 500 ver. 4 from 2005 to 2009: in the third group, 202 patients were treated with SB 500 TCM from 2007 up to present. Biochemical failure was defined according to the Phoenix definition (PSA nadir + 2 ng/ml). The mean age, PSA, Gleason score, operation time, and follow-up period in each group were 68, 66 and 67 years, 11.2, 9.7 and 9.3 ng/ml, 6.2, 6.6 and 6.7, 167, 101 and 106 min, and 56, 48 and 36 months, respectively. The biochemical disease-free rate (bDFR) in each group at 5 years was, respectively, 54%, 61% and 84%, and was 50% at 10 years in the SB200/500 group (pcultural and economic vectors have caused a shift from to minimally invasive techniques.

  14. Distinguishing the Noise and image structures for detecting the correction term and filtering the noise by using fuzzy rules

    Directory of Open Access Journals (Sweden)

    Sridevi.Ravada,

    2011-07-01

    Full Text Available A fuzzy filter is constructed from a set of fuzzy IF-THEN rules, these fuzzy rules come either from human experts or by matching input-output pairs .in this paper we propose a new fuzzy filter for the noise reduction of images corrupted with additive noise. here in this approach ,initially fuzzy derivatives for all eight directions that is N,E,W,S, NE,NW,SE,SW are calculated using “fuzzy IF-THEN rules “ and membership functions . Further the fuzzy derivative values obtained are used in the fuzzy smoothing for determining the correction term. Finally correction term can be added to the processed pixel value. Iteratively apply the fuzzy filter to reduce the noise and at each and every iteration membership function iscalculated based on the remaining noise level. A statistical model for the noise distribution can be incorporated to relate the homogeneity to the adaptation scheme of the membership functions.

  15. Adaptive Lighting

    DEFF Research Database (Denmark)

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper

    2015-01-01

    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... the investigations of lighting scenarios carried out in two test installations: White Cube and White Box. The test installations are discussed as large-scale experiential instruments. In these test installations we examine what could potentially occur when light using LED technology is integrated and...

  16. Noise and Function

    CERN Document Server

    Weinstein, Steven

    2016-01-01

    Noise is widely understood to be something that interferes with a signal or process. Thus, it is generally thought to be destructive, obscuring signals and interfering with function. However, early in the 20th century, mechanical engineers found that mechanisms inducing additional vibration in mechanical systems could prevent sticking and hysteresis. This so-called "dither" noise was later introduced in an entirely different context at the advent of digital information transmission and recording in the early 1960s. Ironically, the addition of noise allows one to preserve information that would otherwise be lost when the signal or image is digitized. As we shall see, the benefits of added noise in these contexts are closely related to the phenomenon which has come to be known as stochastic resonance, the original version of which appealed to noise to explain how small periodic fluctuations in the eccentricity of the earth's orbit might be amplified in such a way as to bring about the observed periodic transiti...

  17. Airport noise and teratogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, L.D.; Layde, P.M.; Erickson, J.D.

    1979-07-01

    It has been suggested that exposure to high-noise levels near major airports may cause increased incidence of birth defects in the offspring of parents residing near these airports. Using data gathered in Metropolitan Atlanta during 1970 to 1972, we compared the rates of seventeen categories of defects in high- and low-noise census tracts. No significant differences were observed. However, when we subdivided the category of central nervous system defects into several subcategories of specific defects, we noted a significantly increased incidence of spina bifida without hydrocephalus in the high-noise areas. Because of the small number of cases associated with this finding we did a matched case-control study using all cases of central nervous system defects born during the years 1968 to 1976. No significantly increased risk for residents in the high-noise areas was noted in this study. It is our opinion that noise or other factors associated with residence near airports are unlikely to be important environmental teratogens.

  18. Extraaural effects of noise

    Energy Technology Data Exchange (ETDEWEB)

    Marth, E.; Gruber, M.; Koeck, M.; Moese, J.R.; Gallasch, E.; Fueger, G.F.

    This study investigates the effects of a short-term exposition (15 sec) to an indifferent, broad spectrum of noise. Noise levels were set at 85 dB(A) and 110 dB(A). Stress mediators and compensatory mechanisms were studied in 30 test persons. The study was particularly concerned with the metabolic processes providing energy for fight or flight reactions. Most importantly triglycerides are hydrolysed in order to be able to produce the fatty acids that are released. This catabolism is a function of an ACTH-activated lipase. In 93% of the person tested, triglycerides decreased by 7 to 40% of the initial concentration. Blood sugar reaction can be described in two phases: Initially, there was a slight increase in the blood sugar concentration; at higher noise levels, it was followed by a slight decrease. This behaviour was even more characteristic of the insulin concentration. At 85 dB(A), no significant difference concentration was found compared with the levels previous to noise exposition. At 110 dB(A), there was a significant decrease in the insulin level. Vaso constriction of the peripheral blood vessels is a useful parameter for the stress caused by noise. This was shown by registering the finger pulse during the test.

  19. Intensify Denoisy Image Using Adaptive Multiscale Product Thresholding

    Directory of Open Access Journals (Sweden)

    Mr. Anup T. Gadre,

    2015-06-01

    Full Text Available This Paper presents a wavelet-based multiscale products thresholding scheme for noise suppression of magnetic resonance images. This paper proposed a method based on image de-noising and edge enhancement of noisy multidimensional imaging data sets. Medical images are generally suffered from signal dependent noises i.e. speckle noise and broken edges. Most of the noises signals appear from machine and environment generally not contribute to the tissue differentiation. But, the noise generated due to above mentioned reason causes a grainy appearance on the image, hence image enhancement is required. For the intent of image denoising, Adaptive Multiscale Product Thresholding based on 2-D wavelet transform is used. In this method, contiguous wavelet sub bands are multiplied to improve edge structure while reducing noise. In multiscale products, boundaries can be successfully distinguished from noise. Adaptive threshold is designed and forced on multiscale products as an alternative of wavelet coefficients or recognize important features. For the edge enhancement. Canny Edge Detection Algorithm is used with scale multiplication technique. Simulation results shows that the planned technique better suppress the Poisson noise among several noises i.e. salt & pepper, speckle noise and random noise. The Performance of Image Intesification can be estimate by means of PSNR, MSE.

  20. Traffic noise and cardiovascular disease

    OpenAIRE

    Selander, Jenny

    2010-01-01

    Traffic noise is an increasing problem in urban areas worldwide, but health effects in relation to traffic noise exposure are not well understood. Several studies show that noise may give rise to acute stress reactions, possibly leading to cardiovascular effects, but the evidence is limited on cardiovascular risks associated with traffic noise exposure. Cardiovascular effects have been indicated for other environmental stressors such as occupational noise exposure and job ...

  1. Monitoring of Noise During Ganeshotsav

    OpenAIRE

    Mrs. P. Saler; Mr. Satyasheel Vibhute

    2011-01-01

    Sound is a form of energy emitted by a vibrating body causing change in pressure of the surrounding elastic medium through which energy is transmitted. Noise has been defined as unwanted sound. Noise is a disturbance to the human environment which is escalating at a high rate. There are numerous effects of noise on human and environment due to the increase in noise pollution slowly, insensibly; we seem to accept noise and the physiological and psychological deterioration that accompanies it a...

  2. Lower Hearing Threshold by Noise

    Institute of Scientific and Technical Information of China (English)

    龙长才; 邵峰; 张燕萍; 秦佑国

    2004-01-01

    We demonstrate that noise can be a benefit factor that enables us to hear weaker signals. We measured the hearing thresholds of subjects for pure tone in different noise levels. The results show that pure tone thresholds with noise of some levels are lower than that without noise. The largest down-shift of the threshold by noise among the examined subjects is 5. 7dB, and the smallest is 1.7dB.

  3. Adaptive Computing.

    Science.gov (United States)

    Harrell, William

    1999-01-01

    Provides information on various adaptive technology resources available to people with disabilities. (Contains 19 references, an annotated list of 129 websites, and 12 additional print resources.) (JOW)

  4. ADAPT Dataset

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Diagnostics and Prognostics Testbed (ADAPT) Project Lead: Scott Poll Subject Fault diagnosis in electrical power systems Description The Advanced...

  5. Road Traffic Noise

    Science.gov (United States)

    Beckenbauer, Thomas

    Road traffic is the most interfering noise source in developed countries. According to a publication of the European Union (EU) at the end of the twentieth century [1], about 40% of the population in 15 EU member states is exposed to road traffic noise at mean levels exceeding 55 dB(A). Nearly 80 million people, 20% of the population, are exposed to levels exceeding 65 dB(A) during daytime and more than 30% of the population is exposed to levels exceeding 55 dB(A) during night time. Such high noise levels cause health risks and social disorders (aggressiveness, protest, and helplessness), interference of communication and disturbance of sleep; the long- and short-term consequences cause adverse cardiovascular effects, detrimental hormonal responses (stress hormones), and possible disturbance of the human metabolism (nutrition) and the immune system. Even performance at work and school could be impaired.

  6. Study of active noise control system for a commercial HVAC unit

    Science.gov (United States)

    Devineni, Naga

    Acoustic noise is a common problem in everyday life. If the appliances that are present in the work and living areas generate noise then it's a serious problem. One such appliance is the Heating, Ventilation and Air-conditioning system (HVAC) in which blower fan and compressor units are housed together. Operation of a HVAC system creates two kinds of noise. One is the noise due to the air flow and the other is the result of the compressor. Both of them exhibit different signal properties and need different strategies to control them. There has been previous efforts in designing noise control systems that can control noise from the HVAC system. These include passive methods which use sound absorption materials to attenuate noise and active methods which cancel noise by generating anti-noise. Passive methods are effective in limiting the high frequency noise, but are inefficient in controlling low frequency noise from the compressor. Compressor noise is one of the strong low frequency components that propagate through the walls, therefore there is need for deploying active signal processing methods that consider the signal properties into consideration to cancel the noise acoustically. The quasi periodic nature of the compressor noise is exploited in noise modeling which aids in implementing an adaptive linear prediction filter in estimating the anti noise [12]. In this thesis, a multi channel architecture has been studied for a specific HVAC system in order to improve noise cancellation by creating larger quiet zone. In addition to the multi-channel architecture, a real time narrow band Active Noise Control (ANC) was employed to cancel noise under practical conditions.

  7. Cross-band noise model refinement for transform domain Wyner–Ziv video coding

    DEFF Research Database (Denmark)

    Huang, Xin; Forchhammer, Søren

    2012-01-01

    TDWZ video coding trails that of conventional video coding solutions, mainly due to the quality of side information, inaccurate noise modeling and loss in the final coding step. The major goal of this paper is to enhance the accuracy of the noise modeling, which is one of the most important aspects...... influencing the coding performance of DVC. A TDWZ video decoder with a novel cross-band based adaptive noise model is proposed, and a noise residue refinement scheme is introduced to successively update the estimated noise residue for noise modeling after each bit-plane. Experimental results show...... that the proposed noise model and noise residue refinement scheme can improve the rate-distortion (RD) performance of TDWZ video coding significantly. The quality of the side information modeling is also evaluated by a measure of the ideal code length....

  8. Application of High Order X-LMS Filter for Active Noise Control

    Directory of Open Access Journals (Sweden)

    N.V.K.Mahalakshmi

    2014-06-01

    Full Text Available In this paper active noise is controlled by using higher order X-LMS (least mean square filter. This technique is based on X-NLMS (normalized least mean square, also known as traditional acoustic noise cancellation (ANC scheme. It cancels the wideband noise from the corrupted speech signal. The active noise reducing headphone is probably the most successful application of active control of sound – the technology of cancelling sound with sound i.e., by using anti-noise signal. This report presents an outlined technical review of noise cancellation in headphones. The principles of passive noise attenuation are presented after which active attenuation is introduced showing how the two complement the attenuation performance. In real-time environment, the number of different applications in which adaptive techniques are being successfully used that are echo cancellation, equalization of dispersive channels, system identification, signal enhancement, noise cancelling and control.

  9. Least Squares Inference on Integrated Volatility and the Relationship between Efficient Prices and Noise

    DEFF Research Database (Denmark)

    Nolte, Ingmar; Voev, Valeri

    The expected value of sums of squared intraday returns (realized variance) gives rise to a least squares regression which adapts itself to the assumptions of the noise process and allows for a joint inference on integrated volatility (IV), noise moments and price-noise relations. In the iid noise...... increasing" type of dependence and analyze its ability to cope with the empirically observed price-noise dependence in quote data. In the empirical section of the paper we apply the LS methodology to estimate the integrated volatility as well as the noise properties of 25 liquid stocks both with midquote and...... transaction price data. We find that while iid noise is an oversimplification, its non-iid characteristics have a decidedly negligible effect on volatility estimation within our framework, for which we provide a sound theoretical reason. In terms of noise-price endogeneity, we are not able to find empirical...

  10. Shot Noise in Graphene

    OpenAIRE

    DiCarlo, L.; Williams, J.R.; Zhang, Yiming; McClure, D. T.; Marcus, C. M.

    2007-01-01

    We report measurements of current noise in single- and multi-layer graphene devices. In four single-layer devices, including a p-n junction, the Fano factor remains constant to within +/-10% upon varying carrier type and density, and averages between 0.35 and 0.38. The Fano factor in a multi-layer device is found to decrease from a maximal value of 0.33 at the charge-neutrality point to 0.25 at high carrier density. These results are compared to theoretical predictions for shot noise in balli...

  11. Community response to noise

    Directory of Open Access Journals (Sweden)

    Takashi Yano

    2012-01-01

    Full Text Available Activities from 2008 to 2011 by ICBEN community response to noise team were summarized. That is, individual community-based indexes such as community tolerance Level, Zuricher Fluglarm Index (ZFI and Frankfurter Fluglarm Index (FFI/FNI were newly proposed, differences in railway bonus between Europe and Asia were discussed by a Swedish survey, socio-acoustic surveys were reported from developing countries, and annoyance equivalents and dominant source models were proposed as the adequate combined noise model. Furthermore, not only negative, but also positive aspects of sound were discussed as soundscape studies. Finally, seven items were listed as future team activities.

  12. Noise Source Location Optimization

    Directory of Open Access Journals (Sweden)

    Ed O’Keefe

    1994-01-01

    Full Text Available This article describes a method to determine locations of noise sources that minimize modal coupling in complex acoustic volumes. Using the acoustic source scattering capabilities of the boundary element method, predictions are made of mode shape and pressure levels due to various source locations. Combining knowledge of the pressure field with a multivariable function minimization technique, the source location generating minimum pressure levels can be determined. The analysis also allows for an objective comparison of “best/worst” locations. The technique was implemented on a personal computer for the U.S. Space Station, predicting 5–10 dB noise reduction using optimum source locations.

  13. Noise sources and noise suppression in CMOS imagers

    Science.gov (United States)

    Pain, Bedabrata; Cunningham, Thomas J.; Hancock, Bruce R.

    2004-01-01

    Mechanisms for noise coupling in CMOS imagers are complex, since unlike a CCD, a CMOS imager has to be considered as a full digital-system-on-a-chip, with a highly sensitive front-end. In this paper, we analyze the noise sources in a photodiode CMOS imager, and model their propagation through the signal chain to determine the nature and magnitude of noise coupling. We present methods for reduction of noise, and present measured data to show their viability. For temporal read noise reduction, we present pixel signal chain design techniques to achieve near 2 electrons read noise. We model the front-end reset noise both for conventional photodiode and CTIA type of pixels. For the suppression of reset noise, we present a column feedback-reset method to reduce reset noise below 6 electrons. For spatial noise reduction, we present the design of column signal chain that suppresses both spatial noise and power supply coupling noise. We conclude by identifying problems in low-noise design caused by dark current spatial distribution.

  14. Adaptive Denoising and Equalization of Infrared Wireless CDMA System

    Directory of Open Access Journals (Sweden)

    Fernando Xavier N.

    2005-01-01

    Full Text Available Infrared has abundant, unregulated bandwidth enabling rapid deployment at low cost. However, safety limits on power emission levels (IEC825, large noise due to ambient lighting, and multipath dispersion remain as hurdles in diffused indoor environments. Especially, the high-frequency periodic interference produced by fluorescent lights is a major concern. Spread spectrum techniques enable low-power operation and noise rejection, at the expense of large processing gain. In this paper, we quantify the noise received and propose an adaptive FIR filter to jointly cancel the multipath dispersion and the fluorescent light noise in an infrared CDMA system. From analytical and simulation results, the adaptive filter significantly enhances the noise rejection capability of the CDMA system and tracks well the quasistationary indoor wireless channel. Our results show tenfold improvement in the BER for a given SNR and processing gain due to the adaptive filter. The filter also performs well in the multiuser environment.

  15. 晚期胰体癌HIFU消融效果与CT靶皮距的相关性%Correlation between ablation effect and CT target skin distance in HIFU on advanced pancreatic body cancer

    Institute of Scientific and Technical Information of China (English)

    葛辉玉; 苗立英; 熊六林; 王金锐; 贾建文; 郑粹闪

    2013-01-01

    Objective To explore the correlation between ablation effect and CT target skin distance (TSD) of advanced pancreatic body carcinoma in high intensity focused ultrasound (HIFU) therapy. Methods Positive ablation associated with HIFU was the tumor ablated over 30% (group A), otherwise it was negative ablation (group B). The correlation between ablation effect and CT TSD was analyzed based on 20 patients of adenocarcinoma of pancreatic body in the late stage that received HIFU therapy. Results The difference of CT TSD between group A and group B was significant (P<0. 05). Increasing of CT TSD by 1 cm would cause reduction of tumor ablation effect by 0. 31. ROC curve predicted that when CT TSD was 7. 15 cm, the sensitivity and specificity of ablation effect was 80. 00% and 70. 00%, respectively, and AUC was 0. 81 (P=0. 02). With reference to clinical practice, 7 cm was set as the critical value for CT TSD in HIFU therapy. Taking this value of CT TSD, the sensitivity and specificity of tumor ablation effect was 77. 80% and 72. 70% , respectively, OR = 9. 33. Conclusion The ablation effect negatively relates to CT TSD in HIFU therapy for pancreatic body carcinomas 7 cm of CT TSD can be set as the critical value for HIFU indications.%目的 探讨晚期胰体癌HIFU消融效果与CT靶皮距的相关性.方法 将HIFU消融体积比>30%定为A组,即存在与HIFU相关的消融;≤30%定为B组,即不明确存在与HIFU相关的消融.根据上述分组,对20例晚期胰体癌肿物消融效果与CT靶皮距的相关性进行分析.结果 A组与B组之间CT靶皮距差异有统计学意义(P<0.05),且CT靶皮距每增加1 cm,消融效果降低0.31倍;ROC曲线显示,当CT靶皮距为7.15 cm时,其预测消融效果的敏感度为80.00%,特异度为70.00%,曲线下面积为0.81(P=0.02).结合临床,将7 cm作为CT靶皮距的分界值,预测消融效果的敏感度和特异度分别为77.80%和72.70%,OR值为9.33.结论 晚期胰体癌HIFU消融效

  16. Spin Hall noise

    NARCIS (Netherlands)

    Kamra, A.; Witek, F.P.; Meyer, S.; Huebl, H.; Geprägs, S.; Gross, R.; Bauer, G.E.W.; Goennenwein, S.T.B.

    2014-01-01

    We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle α between the magnetization and the transport direction. The results are consistent wit

  17. Exploring Noise: Sound Pollution.

    Science.gov (United States)

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  18. Fast Link Adaptation for MIMO-OFDM

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Kant, Shashi; Wehinger, Joachim;

    2010-01-01

    We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple-input–mult......We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple...

  19. Noise synthesis for the Virtual Community Noise Simulator

    OpenAIRE

    Arntzen, M.

    2013-01-01

    Aircraft noise imposes restrictions on possible growth of airports. Noise mitigation measures can be based long-term predictive models but would benefit from high-fidelity simulation of the audible effects. To this end the NLR uses its Virtual Community Noise Simulator (VCNS). Several modelling steps and an application will be demonstrated in this article as to show the promising future of aircraft noise synthesis.

  20. SPEECH ENHANCEMENT BASED ON DYNAMIC NOISE ESTIMATION WITHIN AUTO-CORRELATION DOMAIN

    Institute of Scientific and Technical Information of China (English)

    吴亚栋; 吴旭辉

    2002-01-01

    Most noise suppression algorithms of single channel use the mean of noisy segments to estimate the characteristics of noise spectrum, ignoring the estimation of noise in speech segments. Therefore, when the energy level of noise varies with the time, the performance of removing noise will be degraded. To solve this problem, a speech enhancement approach based on dynamic noise estimation within correlation domain was proposed. This method exploits the characteristics that noise energy mainly concentrates on 0 th-order correlation coefficients, signal is auto-correlated but signal and noise, noise and noise are uncorrelated, then estimates and decomposes the noise, thus helps to solve the above-mentioned problem. The results of recognition experiments on speech signals of 15 Chinese cities' names corrupted by noise of exhibition hall shows, this approach is better than SS (Spectral Subtraction) method, adapts better to the variances of energy levels of speech signal corrupted by noise, has some practicability to improve the robustness of recognition systems under noisy environment.

  1. Hybrid Active Noise Control using Adjoint LMS Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Hyun Do; Hong, Sik Ki [Dankook University (Korea, Republic of)

    1998-07-01

    A multi-channel hybrid active noise control(MCHANC) is derived by combining hybrid active noise control techniques and adjoint LMS algorithms, and this algorithm is applied to an active noise control system in a three dimensional enclosure. A MCHANC system uses feed forward and feedback filters simultaneously to cancel noises in an enclosure. The adjoint LMs algorithm, in which the error is filtered through an adjoint filter of the secondary channel, is also used to reduce the computational burden of adaptive filters. The overall attenuation performance and convergence characteristics of MCHANC algorithm is better than both multiple-channel feed forward algorithms and multiple-channel feedback algorithms. In a large enclosure, the acoustic reverberation can be very long, which means a very high order feed forward filter must be used to cancel the reverberation noises. Strong reverberation noises are generally narrow band and low frequency, which can be effectively predicted and canceled by a feedback adaptive filters. So lower order feed forward filter taps can be used in MCHANC algorithm which combines advantages of fast convergence and small excess mean square error. In this paper, computer simulations and real time implementations is carried out on a TMS320C31 processor to evaluate the performance of the MCHANC systems. (author). 11 refs., 11 figs., 1 tab.

  2. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, F.R.; Poulsen, Torben

    2001-01-01

    The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

  3. Annoyance of low frequency noise and traffic noise

    DEFF Research Database (Denmark)

    Mortensen, Frank Rysgaard; Poulsen, Torben

    2000-01-01

    The annoyance of different low frequency noise sources was determined and compared to the annoyance from traffic noise. Twenty-two test subjects participated in laboratory listening tests. The sounds were presented by loudspeakers in a listening room and the spectra of the low frequency noises were...

  4. Noise sensitivity and reactions to noise and other environmental conditions

    NARCIS (Netherlands)

    Miedema, H.M.E.; Vos, H.

    2003-01-01

    This article integrates findings from the literature and new results regarding noise sensitivity. The new results are based on analyses of 28 combined datasets (N=23 038), and separate analyses of a large aircraft noise study (N=10939). Three topics regarding noise sensitivity are discussed, namely,

  5. The Traffic Noise Index: A Method of Controlling Noise Nuisance.

    Science.gov (United States)

    Langdon, F. J.; Scholes, W. E.

    This building research survey is an analysis of the social nuisance caused by urban motor ways and their noise. The Traffic Noise Index is used to indicate traffic noises and their effects on architectural designs and planning, while suggesting the need for more and better window insulation and acoustical barriers. Overall concern is for--(1)…

  6. Evaluating noise abatement measures using strategic noise maps

    NARCIS (Netherlands)

    Borst, H.C.; Miedema, H.M.E.; Laan, W.P.N. van der; Lohman, W.J.A.

    2006-01-01

    Noise annoyance due to transportation is widespread in industrialized countries and in urban areas in the developing countries. The European Noise Directive (END) requires an assessment of the noise situation as well as the formulation of action plans for the reduction of the number of people harmfu

  7. A new method for adaptive color image filtering

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An adaptive color image filter (ACIF) is proposed in this note. Through analyzing noise corruption of color image, efficient locally adaptive filters are chosen for image enhancement. The proposed adaptive color image filter combines advantages of both nonlinear vector filters and linear filters, it attenuates noise and preserves edges and details very well. Experimental results show that the proposed filter performs better than vector median filter, directional-distance filter, directional-magnitude vector filter, adaptive nearest-neighbor filter, and -trimmed mean filter.

  8. Rapidly converging multichannel controllers for broadband noise and vibrations

    NARCIS (Netherlands)

    Berkhoff, A.P.

    2010-01-01

    Applications are given of a preconditioned adaptive algorithm for broadband multichannel active noise control. Based on state-space descriptions of the relevant transfer functions, the algorithm uses the inverse of the minimum-phase part of the secondary path in order to improve the speed of converg

  9. An Adaptive UKF Based SLAM Method for Unmanned Underwater Vehicle

    OpenAIRE

    Hongjian Wang; Guixia Fu; Juan Li; Zheping Yan; Xinqian Bian

    2013-01-01

    This work proposes an improved unscented Kalman filter (UKF)-based simultaneous localization and mapping (SLAM) algorithm based on an adaptive unscented Kalman filter (AUKF) with a noise statistic estimator. The algorithm solves the issue that conventional UKF-SLAM algorithms have declining accuracy, with divergence occurring when the prior noise statistic is unknown and time-varying. The new SLAM algorithm performs an online estimation of the statistical parameters of unknown system noise by...

  10. Blue-noise remeshing with farthest point optimization

    KAUST Repository

    Yan, Dongming

    2014-08-01

    In this paper, we present a novel method for surface sampling and remeshing with good blue-noise properties. Our approach is based on the farthest point optimization (FPO), a relaxation technique that generates high quality blue-noise point sets in 2D. We propose two important generalizations of the original FPO framework: adaptive sampling and sampling on surfaces. A simple and efficient algorithm for accelerating the FPO framework is also proposed. Experimental results show that the generalized FPO generates point sets with excellent blue-noise properties for adaptive and surface sampling. Furthermore, we demonstrate that our remeshing quality is superior to the current state-of-the art approaches. © 2014 The Eurographics Association and John Wiley & Sons Ltd.

  11. Application of Tamura texture analysis in monitoring HIFU ablation of rabbit VX2 breast tumor%Tamura 纹理分析在声像图监控 HIFU 消融兔 VX2乳腺肿瘤中的应用

    Institute of Scientific and Technical Information of China (English)

    闵加艳; 邹建中; 郭宇; 王冬

    2012-01-01

    To evaluate Tamura texture parameters in judging the coagulative necrosis of target tissues under the treatment of the high intensity focused ultrasound (HIFU). Methods Totally 120 New Zealand rabbits were randomly divided into 3 groups according to different irradiation intensities of HIFU for 3 s targeted on the VX2 breast tumors of the rabbits, i. e. 90 W group (n = 40) , 120 W group (n = 40) and 150 W group (n = 40). The ultrasonography obtained before and immediately after irradiation and 3 eigenvalues of Tamura texture parameters (directionality, roughness and contrast) were extracted. By selecting these obtained parameters through a support vector machine, the data were analyzed. Results The sensitivity, specificity and accuracy rate of Tamura texture analyses was 89. 71% (61/68) , 69. 23% (36/52) and 80. 83% (97/120) , of gray was 57. 35% (39/68), 63. 46% (33/52) and 60. 00% (72/120). The sensitivity and accuracy rate of the former were higher than those of the latter (both P<0. 001). The accuracy rate of Tamura texture analyses in 90 W group and 120 W were higher than that of gray [77. 50% (31/40) vs 50. 00% (20/40) , P=0. 011; 80. 00% (32/40) vs 55. 00% (22/40) , P = 0.017]. Conclusion With more advantages than gray evaluation, Tamura texture analysis is applicable for the judgment of coagulative necrosis.%目的 探讨Tamura纹理参数对声像图监控高强度聚焦超声(HIFU)辐照下靶组织凝固性坏死情况的评价效果.方法 根据HIFU辐照兔VX2乳腺肿瘤的辐照强度,将120只新西兰白兔随机分为90 W、120 W、150W组,每组40只,辐照时间均为3 s.采集辐照前和辐照后即刻的声像图,提取Tamura纹理参数中的方向度、粗糙度和对比度;通过支撑适量机筛选,获得决策超平面,并对结果进行分析.结果 Tamura判断凝固性坏死的敏感度为89.71%(61/68),特异度为69.23%(36/52),准确率为80.83%(97/120);灰度判断凝固性坏死的敏感度为57.35%(39/68),

  12. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is ... I find additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound ...

  13. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other words......, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like...... spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier....

  14. Multichannel active control of random noise in a small reverberant room

    DEFF Research Database (Denmark)

    Laugesen, Søren; Elliott, Stephen J.

    1993-01-01

    An algorithm for multichannel adaptive IIR (infinite impulse response) filtering is presented and applied to the active control of broadband random noise in a small reverberant room. Assuming complete knowledge of the primary noise, the theoretically optimal reductions of acoustic energy are init...

  15. Design and Implementation of Noise Free Audio Speech Signal Using Fast Block Least Mean Square Algorithm

    Directory of Open Access Journals (Sweden)

    J. Jebastine

    2012-06-01

    Full Text Available This paper describes the development of an adaptive noise cancellation algorithm for effective recognition of speech signal and also to improve SNR for an adaptive step size input. An adaptive filter with Fast Block Least Mean square Algorithm is designed for noise free audio (speech/music signals. The signal input used is a audio speech signal which could be in the form of a recorded voice. The filter used is adaptive filter and the algorithm used is Fast Block LMS algorithm. A Gaussian noise is added to this input signal and given as a input to the Fast Block LMS. The algorithm is implemented in Matlab and was tested for noise cancellation in speech signals. A Simulink model is designed which results in a noise free audio speech signal at the output. The FBLMS algorithm is computationally efficient in noise cancellation. The noise level in speech signal can be 1 mild, 2 moderate, 3 severe. The SNR is estimated by varying the adaptive step size.

  16. SVD-Based Optimal Filtering Technique for Noise Reduction in Hearing Aids Using Two Microphones

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Maj

    2002-04-01

    Full Text Available We introduce a new SVD-based (Singular value decomposition strategy for noise reduction in hearing aids. This technique is evaluated for noise reduction in a behind-the-ear (BTE hearing aid where two omnidirectional microphones are mounted in an endfire configuration. The behaviour of the SVD-based technique is compared to a two-stage adaptive beamformer for hearing aids developed by Vanden Berghe and Wouters (1998. The evaluation and comparison is done with a performance metric based on the speech intelligibility index (SII. The speech and noise signals are recorded in reverberant conditions with a signal-to-noise ratio of 0 dB and the spectrum of the noise signals is similar to the spectrum of the speech signal. The SVD-based technique works without initialization nor assumptions about a look direction, unlike the two-stage adaptive beamformer. Still, for different noise scenarios, the SVD-based technique performs as well as the two-stage adaptive beamformer, for a similar filter length and adaptation time for the filter coefficients. In a diffuse noise scenario, the SVD-based technique performs better than the two-stage adaptive beamformer and hence provides a more flexible and robust solution under speaker position variations and reverberant conditions.

  17. How CANMET tests noise pollution

    Energy Technology Data Exchange (ETDEWEB)

    Savich, M.U.

    1983-07-01

    The paper describes a noise control program that CANMET has developed to protect miners from permanent hearing loss. Studies at a uranium mine at Elliot Lake were used to reach three objectives: first to identify main underground job categories by noise exposure index; second to measure cyclical noise; and third to establish the effectiveness of ear muffs used in mines. Some of the data obtained is included. Several recommendations for noise control are made.

  18. Adaptive transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-01-01

    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  19. Practical Ranges of Loudness Levels of Various Types of Environmental Noise, Including Traffic Noise, Aircraft Noise, and Industrial Noise

    Directory of Open Access Journals (Sweden)

    Sabine A. Janssen

    2011-05-01

    Full Text Available In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A‑weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels.

  20. Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise.

    Science.gov (United States)

    Salomons, Erik M; Janssen, Sabine A

    2011-06-01

    In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A-weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels. PMID:21776205