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Krieg, F., J. Kirchhof, S. Kodera, S. Lugin, A. Ihlow, T. Schwender, G. del Galdo, F. Römer, and A. Osman. "SAFT processing for manually acquired ultrasonic measurement data with 3D smartInspect." Insight - Non-Destructive Testing and Condition Monitoring 61, no. 11 (November 1, 2019): 663–69. http://dx.doi.org/10.1784/insi.2019.61.11.663.
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The architecture and implementation of a system for synthetic aperture focusing technique (SAFT) reconstruction on ultrasonic data acquired using a hand-held device is described. The reconstruction and the measurement process are performed simultaneously, with the goal of providing instantaneous highly focused visual feedback to the engineer. The implementation is based on the 3D smartInspect system that is currently being developed at Fraunhofer Institute for Nondestructive Testing IZFP. This system assists engineers by recording, displaying and protocolling manually acquired data. In this paper, it is shown that it is possible to enhance this system by adding simultaneous SAFT processing on top of the existing functionality. This improves the imaging quality of the system. Possible limitations on the imaging quality are investigated by real-world hardware set-ups using numerical studies.
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Mayer, Klaus, Karl-Jörg Langenberg, Martin Krause, Boris Milmann, and Frank Mielentz. "Characterization of Reflector Types by Phase-Sensitive Ultrasonic Data Processing and Imaging." Journal of Nondestructive Evaluation 27, no. 1-3 (July 1, 2008): 35–45. http://dx.doi.org/10.1007/s10921-008-0035-3.
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Gao, Xiao Ming. "The Implement of B-Ultrasonic Image Acquisition Based on Camera Interface." Applied Mechanics and Materials 513-517 (February 2014): 3801–4. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.3801.
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B-ultrasonic is widely used in medical diagnostics and other fields, because of its non-invasive, no radiation, etc. Early B-ultrasonic with analog imaging system cant achieve B-ultrasonic image processing, data storage and other operations. With the development of computer technology and electronic technology, Digital B-ultrasonic systems are increasingly used in actual diagnosis, the paper through the use of digital imaging system to achieve B-ultrasonic front ultrasound imaging, reuse embedded microcontrollers Camera interface for B-ultrasonic acquisition of image data, and on this platform to achieve a B-ultrasonic application software development. System testing show that the system data acquisition is stability, and easy to operate, reliable, also can be widely used in medical and industrial ultrasonic fields. Key words: B-ultrasonic; Data Acquisition; Camera; Digitizing
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Gehlbach, Steve M., and F. Graham Sommer. "Frequency Diversity Speckle Processing." Ultrasonic Imaging 9, no. 2 (April 1987): 92–105. http://dx.doi.org/10.1177/016173468700900202.
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Ultrasonic waveform data from a tissue-mimicking phantom containing low contrast targets was digitized, stored and processed prior to creating and displaying ultrasonic images. Speckle reduction was performed by digital filtering of the waveform data with appropriately spaced and weighted digital filters, prior to both coherent and incoherent image averaging. The resultant images showed increased signal-to-noise ratios, consistent with theory. Better definition of low contrast target boundaries was noted in the processed, compared to unprocessed, images. Incoherent and coherent processing were investigated, and appeared to be equivalent.
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Hoyle, C., M. Sutcliffe, P. Charlton, S. Mosey, and I. Cooper. "Limited-angle ultrasonic tomography back-projection imaging." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 1 (January 1, 2021): 20–28. http://dx.doi.org/10.1784/insi.2021.63.1.20.
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Ultrasonic inspection of through-transmission is limited due to the inability to obtain defect depth information. Loss of signal is used as the only indicator, providing lateral defect information. This is often a problem in ultrasonic inspection. Radiographic acquisition techniques, where the X-ray source acts as the transmitter and the detector as the receiver, are conceptionally similar to ultrasonic through-transmission. In the latter, the tomography back-projection method is used to reconstruct images of an object that has been subjected to a minimum of 180° of rotation, to allow for full coverage of the item. In this paper, a novel approach based on back-projection is presented to improve image resolution and defect detectability. Two ultrasonic transducers in through-transmission configuration are utilised to capture data for image processing. The rotation of the transmitter and receiver is not possible in this set-up and, therefore, the reconstruction relies on the artificial generation of a limited rotation. Two probes are aligned either side of the material and are used to gather the ultrasonic signals. These signals are processed before the reconstruction algorithm is applied to them. Various processing and imaging reconstruction algorithms are explored, building on the basic back-projection method to obtain images that are better focused. This technique could be used within materials where there are high attenuation levels and, therefore, traditional pulse-echo is not feasible.
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Deng, Yufeng, Ned C. Rouze, Mark L. Palmeri, and Kathryn R. Nightingale. "Ultrasonic Shear Wave Elasticity Imaging Sequencing and Data Processing Using a Verasonics Research Scanner." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 64, no. 1 (January 2017): 164–76. http://dx.doi.org/10.1109/tuffc.2016.2614944.
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Naik, H. Rama Murthy, J. Jerald, and N. Rajesh Mathivanan. "Impact Damage Detection in GFRP Laminates through Ultrasonic Imaging." Advanced Materials Research 585 (November 2012): 337–41. http://dx.doi.org/10.4028/www.scientific.net/amr.585.337.
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Composite materials are increasingly used in aerospace, naval and automotive vehicles due to their high specific strength and stiffness. In the area of Non destructive testing, ultrasonic C-scans are used frequently to detect defects in composite components caused during fabrication and damage resulting from service conditions. Ultrasonic testing uses transmission of high frequency sound waves into a material to detect imperfections or to locate changes in material properties. The most commonly used ultrasonic testing technique is pulse echo and through transmission wherein sound is introduced into a test object and reflections (echoes) are returned to a receiver from internal imperfections. Under low-velocity impact loading delaminating is observed to be a major failure mode. This report presents the use of above two techniques to detect the damage in glass fiber reinforced plastic (GFRP) laminates. Pulse echo is used to locate the exact position of damage and through transmission is used to know the magnitude of damage in composite. This paper work will be carried out on two different thicknesses and at impact energy levels varying from 7 to 53J. The ensuring delamination damage will be determined by ultrasonic C-scans using the pulse-echo immersion method for through transmission. Delamination areas were quantified accurately by processing the raw image data using a digital image processing technique. Based on the data obtained, correlation will be established between the delamination area and the impact energy.
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Ma, Hong Wei, Ming Dong, Yuan Chen, and Qing Hua Mao. "Development of Ultrasonic Automatic Testing System for Flaws of Rotary Parts." Applied Mechanics and Materials 128-129 (October 2011): 575–79. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.575.
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In order to conquer the disadvantages of undetection, misjudgment and low-efficiency in ultrasonic A-scan testing for rotary parts, an ultrasonic automatic imaging system was developed, and automatic scan device was specially designed for rotary parts. Moreover, the testing software was programmed by LabWindows/CVI, which achieves the acquisition and processing of ultrasonic signals, and displays A, B, C, D and P-scan image. On the basis of storing A-scan data and transforming non-isotropic resolution B-scan image into isotropic one, P-scan imaging is realized. Medium filtering was applied to A-scan signal and C-scan image and the Signal-to-Noise is improved. The experimental results show that this system has well achieved numeralization, automatization and imaging of ultrasonic testing.
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Müller, Sabine, Ernst Niederleithinger, and Thomas Bohlen. "Reverse Time Migration: A Seismic Imaging Technique Applied to Synthetic Ultrasonic Data." International Journal of Geophysics 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/128465.
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Ultrasonic echo testing is a more and more frequently used technique in civil engineering to investigate concrete building elements, to measure thickness as well as to locate and characterise built-in components or inhomogeneities. Currently the Synthetic Aperture Focusing Technique (SAFT), which is closely related to Kirchhoff migration, is used in most cases for imaging. However, this method is known to have difficulties to image steeply dipping interfaces as well as lower boundaries of tubes, voids or similar objects. We have transferred a processing technique from geophysics, the Reverse Time Migration (RTM) method, to improve the imaging of complicated geometries. By using the information from wide angle reflections as well as from multiple events there are fewer limitations compared to SAFT. As a drawback the required computing power is significantly higher compared to the techniques currently used. Synthetic experiments have been performed on polyamide and concrete specimens to show the improvements compared to SAFT. We have been able to image vertical interfaces of step-like structures as well as the lower boundaries of circular objects. It has been shown that RTM is a step forward for ultrasonic testing in civil engineering.
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Liang, Haidong-Dong, Chun Sing Louis Tsui, Michael Halliwell, and Peter N. T. Wells. "Continuous wave ultrasonic Doppler tomography." Interface Focus 1, no. 4 (June 2011): 665–72. http://dx.doi.org/10.1098/rsfs.2011.0018.
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In continuous wave ultrasonic Doppler tomography (DT), the ultrasonic beam moves relative to the scanned object to acquire Doppler-shifted frequency spectra which correspond to cross-range projections of the scattering and reflecting structures within the object. The relative motion can be circular or linear. These data are then backprojected to reconstruct the two-dimensional image of the object cross section. By using coherent processing, the spatial resolution of ultrasonic DT is close to an order of magnitude better than that of traditional pulse-echo imaging at the same ultrasound frequency.
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Tran, Dai Quoc, Ju-Won Kim, Kassahun Demissie Tola, Wonkyu Kim, and Seunghee Park. "Artificial Intelligence-Based Bolt Loosening Diagnosis Using Deep Learning Algorithms for Laser Ultrasonic Wave Propagation Data." Sensors 20, no. 18 (September 17, 2020): 5329. http://dx.doi.org/10.3390/s20185329.
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The application of deep learning (DL) algorithms to non-destructive evaluation (NDE) is now becoming one of the most attractive topics in this field. As a contribution to such research, this study aims to investigate the application of DL algorithms for detecting and estimating the looseness in bolted joints using a laser ultrasonic technique. This research was conducted based on a hypothesis regarding the relationship between the true contact area of the bolt head-plate and the guided wave energy lost while the ultrasonic waves pass through it. First, a Q-switched Nd:YAG pulsed laser and an acoustic emission sensor were used as exciting and sensing ultrasonic signals, respectively. Then, a 3D full-field ultrasonic data set was created using an ultrasonic wave propagation imaging (UWPI) process, after which several signal processing techniques were applied to generate the processed data. By using a deep convolutional neural network (DCNN) with a VGG-like architecture based regression model, the estimated error was calculated to compare the performance of a DCNN on different processed data set. The proposed approach was also compared with a K-nearest neighbor, support vector regression, and deep artificial neural network for regression to demonstrate its robustness. Consequently, it was found that the proposed approach shows potential for the incorporation of laser-generated ultrasound and DL algorithms. In addition, the signal processing technique has been shown to have an important impact on the DL performance for automatic looseness estimation.
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Ye, Jiaxing, Shunya Ito, and Nobuyuki Toyama. "Computerized Ultrasonic Imaging Inspection: From Shallow to Deep Learning." Sensors 18, no. 11 (November 7, 2018): 3820. http://dx.doi.org/10.3390/s18113820.
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For many decades, ultrasonic imaging inspection has been adopted as a principal method to detect multiple defects, e.g., void and corrosion. However, the data interpretation relies on an inspector’s subjective judgment, thus making the results vulnerable to human error. Nowadays, advanced computer vision techniques reveal new perspectives on the high-level visual understanding of universal tasks. This research aims to develop an efficient automatic ultrasonic image analysis system for nondestructive testing (NDT) using the latest visual information processing technique. To this end, we first established an ultrasonic inspection image dataset containing 6849 ultrasonic scan images with full defect/no-defect annotations. Using the dataset, we performed a comprehensive experimental comparison of various computer vision techniques, including both conventional methods using hand-crafted visual features and the most recent convolutional neural networks (CNN) which generate multiple-layer stacking for representation learning. In the computer vision community, the two groups are referred to as shallow and deep learning, respectively. Experimental results make it clear that the deep learning-enabled system outperformed conventional (shallow) learning schemes by a large margin. We believe this benchmarking could be used as a reference for similar research dealing with automatic defect detection in ultrasonic imaging inspection.
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Wang, Chuangnan, Thomas Connolley, Iakovos Tzanakis, Dmitry Eskin, and Jiawei Mi. "Characterization of Ultrasonic Bubble Clouds in A Liquid Metal by Synchrotron X-ray High Speed Imaging and Statistical Analysis." Materials 13, no. 1 (December 20, 2019): 44. http://dx.doi.org/10.3390/ma13010044.
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Quantitative understanding of the interactions of ultrasonic waves with liquid and solidifying metals is essential for developing optimal processing strategies for ultrasound processing of metal alloys in the solidification processes. In this research, we used the synchrotron X-ray high-speed imaging facility at Beamline I12 of the Diamond Light Source, UK to study the dynamics of ultrasonic bubbles in a liquid Sn-30wt%Cu alloy. A new method based on the X-ray attenuation for a white X-ray beam was developed to extract quantitative information about the bubble clouds in the chaotic and quasi-static cavitation regions. Statistical analyses were made on the bubble size distribution, and velocity distribution. Such rich statistical data provide more quantitative information about the characteristics of ultrasonic bubble clouds and cavitation in opaque, high-temperature liquid metals.
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Nguyen, Luan T., and Erik H. Saenger. "Guided ultrasonic wavefield cross-correlation with a curved array for high-resolution plate inspection." Journal of Geophysics and Engineering 17, no. 3 (February 27, 2020): 451–62. http://dx.doi.org/10.1093/jge/gxaa004.
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Abstract We present in this work an ultrasonic imaging technique based on wavefield cross-correlation that has potential for high-resolution inspecting of plates and plate-like structures. A curved transmit/receive array setup is used for acquiring wide-aperture waveform data beneficial for applying the presented imaging condition. An additional dispersion analysis using waveform data received by a linear array allows one to reveal the excited guided wave modes and possibly determine the shear wave velocity as an input parameter in the 3D wavefield simulation. Using synthetic but realistic data generated by realistic 3D simulations, we demonstrate the invariance of the time reversal process and the capability of the presented imaging approach for ultrasonic testing based on Lamb waves. In addition to the ability to localise and size multiple defects simultaneously, this imaging approach does not require baseline data and involves only minimal waveform data pre-processing.
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Mohammadkhani, Reza, Luca Zanotti Fragonara, Janardhan Padiyar M., Ivan Petrunin, João Raposo, Antonios Tsourdos, and Iain Gray. "Improving Depth Resolution of Ultrasonic Phased Array Imaging to Inspect Aerospace Composite Structures." Sensors 20, no. 2 (January 20, 2020): 559. http://dx.doi.org/10.3390/s20020559.
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In this paper, we present challenges and achievements in development and use of a compact ultrasonic Phased Array (PA) module with signal processing and imaging technology for autonomous non-destructive evaluation of composite aerospace structures. We analyse two different sets of ultrasonic scan data, acquired from 5 MHz and 10 MHz PA transducers. Although higher frequency transducers promise higher axial (depth) resolution in PA imaging, we face several signal processing challenges to detect defects in composite specimens at 10 MHz. One of the challenges is the presence of multiple echoes at the boundary of the composite layers called structural noise. Here, we propose a wavelet transform-based algorithm that is able to detect and characterize defects (depth, size, and shape in 3D plots). This algorithm uses a smart thresholding technique based on the extracted statistical mean and standard deviation of the structural noise. Finally, we use the proposed algorithm to detect and characterize defects in a standard calibration specimen and validate the results by comparing to the designed depth information.
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Saidov, B. B., and V. F. Telezhkin. "OPTO-ULTRASONIC COMMUNICATION CHANNELS." Bulletin of the South Ural State University. Ser. Computer Technologies, Automatic Control & Radioelectronics 20, no. 4 (December 2020): 55–62. http://dx.doi.org/10.14529/ctcr200406.
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Ultrasound is widely used in various applications, such as monitoring the state of structures, biomed-ical ultrasound imaging, and information (data) transmission. Ultrasonic transceivers are one of the modern communication systems, both for short-range and remote access. Indeed, the technology of the process of transmitting information using communication channels based on ultrasonic (US) vi-brations and the physical implementation of transmission using optical fiber are widely used in con-ditions of confidentiality of data processing. At the same time, the needs of wireless and wired communication demanded the development of more advanced applications (software, hardware solutions). In particular, new challenges have arisen requiring transceivers to have high frequency, wide bandwidth and compact size. Aim. Consider the “technology – opto-ultrasonic” approach used in data transmission and reception channels. This technology involves the generation of ultrasound by a pulse using the optical-acoustic effect, followed by the reception and processing of ultrasonic vibrations. Optical ultrasonic transceivers based on the photo-acoustic (US) principle of operation have great potential, in particular, to obtain the necessary: (super high) frequency of the transmitted signal; wide bandwidth (speed); ease of use as transceivers; low manufacturing cost. Materials and methods. Various methods of spectral analysis (Fourier and Wavelet) have been in-vestigated to ensure the achievement of the above goal. Results. Compared to traditional technolo-gies of information reception and transmission, optical ultrasonic transceivers provide high-frequency communication, wide bandwidth and compact size. Conclusion. The paper investigates the methods of spectral analysis (Fourier and Wavelet) and proposes, based on these studies, possi-ble options for the implementation of optical ultrasonic transceivers that can generate ultrasonic pulses with a duration on a nanosecond scale using an ultrafast laser and receive confidential data with a high degree of security. At the same time, by combining the principle of generating photo-acoustic ultrasound with the use of optical fiber, it is possible to obtain compact and inexpensive ul-trasonic transceivers.
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Anderson, Brian E. "Signal Processing: Data analysis, machine learning, and imaging sources." Journal of the Acoustical Society of America 146, no. 4 (October 2019): 2870. http://dx.doi.org/10.1121/1.5136960.
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Li, Qiu Feng, Hong Guang Liu, Hui Cong Ma, and Zhen Hua Chen. "Study on Improved Computed Tomography Algorithm in Concrete Structure." Applied Mechanics and Materials 189 (July 2012): 401–5. http://dx.doi.org/10.4028/www.scientific.net/amm.189.401.
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In ultrasonic CT of concrete structure, ray tracing technology based on SNELL principle is far more meet the characteristics of ultrasonic propagation. Inversion algorithm of tomography imaging is to solve large sparse equations. Simultaneous iterative reconstruction technique (SIRT) algorithm solves the problem from the mathematical view. According to engineering application, A improved imaging reconstruction method is proposed in the basis. During the data processing of simulation, the data weighting matrix is introduced to increase the proportion of effective information firstly; And then the units without ray passing through is merged with its adjacent units so that the slow-wave in reconstruction section could be changed smoothly by using unit merger method and ensure high resolution in middle section; And finally the image of CT reconstruction is obtained. Simulation results show that the improved algorithm is effective and could meet engineering requirement.
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Eyding, Jens, Christian Fung, Wolf-Dirk Niesen, and Christos Krogias. "Twenty Years of Cerebral Ultrasound Perfusion Imaging—Is the Best yet to Come?" Journal of Clinical Medicine 9, no. 3 (March 17, 2020): 816. http://dx.doi.org/10.3390/jcm9030816.
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Over the past 20 years, ultrasonic cerebral perfusion imaging (UPI) has been introduced and validated applying different data acquisition and processing approaches. Clinical data were collected mainly in acute stroke patients. Some efforts were undertaken in order to compare different technical settings and validate results to gold standard perfusion imaging. This review illustrates the evolution of the method, explicating different technical aspects and milestones achieved over time. Up to date, advancements of ultrasound technology as well as data processing approaches enable semi-quantitative, gold standard proven identification of critically hypo-perfused tissue in acute stroke patients. The rapid distribution of CT perfusion over the past 10 years has limited the clinical need for UPI. However, the unexcelled advantage of mobile application raises reasonable expectations for future applications. Since the identification of intracerebral hematoma and large vessel occlusion can also be revealed by ultrasound exams, UPI is a supplementary multi-modal imaging technique with the potential of pre-hospital application. Some further applications are outlined to highlight the future potential of this underrated bedside method of microcirculatory perfusion assessment.
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Guo, Xufei, Yan Han, and Pengfei Nie. "Ultrasound Imaging Algorithm: Half-Matrix Focusing Method Based on Reciprocity." Mathematical Problems in Engineering 2021 (February 2, 2021): 1–11. http://dx.doi.org/10.1155/2021/8888469.
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The ultrasonic phased array total focusing method (TFM) has the advantages of high imaging signal-to-noise ratio (SNR) and high defect resolution, but the problem of large amount data capturing and processing limits its practical industrial applications. To reduce the imaging calculation demand of the total focusing method, a half-matrix focusing method (HFM) is proposed based on the acoustic reciprocity. The method simplifies the calculation process of full-matrix data capturing (FMC) and total focus imaging. The experimental results show that the signal obtained by the linear array transceiver sensor is highly consistent, and the imaging resolution and signal-to-noise ratio of the half-matrix focusing method are slightly lower than those of full-matrix focusing method and higher than those of the B-scan imaging. However, compared with TFM, data acquisition and computational efficiency using the HFM have been improved significantly.
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Herment, A., J. P. Guglielmi, P. Péronneau, and Ph Dumée. "High-Resolution, Reflection Mode Tomographic Imaging Part II: Application to Echography." Ultrasonic Imaging 11, no. 1 (January 1989): 22–41. http://dx.doi.org/10.1177/016173468901100102.
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Principles of high-resolution, ultrasonic imaging using data acquisition by a compound scanning with a sector echograph are presented. The signal processing is based on both deconvolution and reflection mode tomography. Three of the methods that can be derived from these principles are selected due to their lower computation costs. Applications of these methods to synthetic data and test targets demonstrate that, with respect to 2D deconvolution, they offer: a gain in computation time of more than 8, an improvement in resolution of the order of 10 and an increase of S/N ratio of the order of 4. Finally, both the effects of limited acquisition angular window and of a variable propagation speed are illustrated.
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Ahmed, Hasan, and Jung-Ryul Lee. "Development of autonomous target recognition and scanning technology for pulse-echo ultrasonic propagation imager." Structural Health Monitoring 19, no. 4 (September 24, 2019): 1064–74. http://dx.doi.org/10.1177/1475921719874823.
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This article proposes a pulse-echo ultrasonic propagation imaging system that is capable of autonomous target recognition and scanning an area of a customizable shape for the non-destructive evaluation of structural defects. The proposed system employs through-the-thickness bulk waves for ultrasonic inspection, which is achieved by joining two laser beams: one each for the ultrasonic wave generation and sensing. Moreover, the system is capable of autonomously suggesting a suitable inspection area for a specimen placed in front of the scanning head. The scan area delimitation algorithm uses the specimen image and ascertains the specimen border by means of edge and contour detection operations, following which a scan area closely conforming to the specimen boundary is suggested. The system can scan an area of any arbitrary shape, thereby preventing any wasteful operations that may result from fixed shape (rectangular or square) scanning. A Q-switched laser is used for generating the aforementioned ultrasonic waves, while a laser Doppler vibrometer is used for sensing these signals. A dual-axis automated translation stage is applied for raster scanning of the specimen, and a data acquisition card is employed for taking measurements. A camera mounted on the scan head is used for imaging the specimen for the scan area detection. Graphical user interface software controls all the individual blocks of the system, while implementing the required image processing, scan area detection, signal acquisition, signal processing, and result display. The graphical user interface is created in C++ using the Qt framework. Moreover, Qt Widgets for Technical Applications is used for the result display, and the Open Source Computer Vision Library is employed for the implementation of basic image processing algorithms. Multi-threading is used for real-time updating of the scan results while the scanning is ongoing.
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Yamamoto, Tokuo, and Howoong Shon. "Data processing for high‐resolution 3‐D subbottom imaging system ‘‘kite.’’." Journal of the Acoustical Society of America 91, no. 4 (April 1992): 2464. http://dx.doi.org/10.1121/1.403046.
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Sun, Hong Chun, Da Long Zhang, and Shao Kun Wu. "Overview of Ultrasound Imaging Algorithms Based on Synthetic Aperture Focusing Technique." Advanced Materials Research 712-715 (June 2013): 2051–54. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.2051.
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Synthetic aperture focusing ultrasound imaging technique used signal processing method to analysis ultrasonic echo data. It let the performance of transducer with small apertures be as well as the transducer with large aperture. It can still obtain high azimuth resolution image and form three-dimensional image, when it was operated at lower operating frequency. This paper describes the history and the theory of synthetic aperture focusing ultrasound imaging technology. It also contains the development of the synthetic aperture focusing ultrasound imaging technology in China and at abroad. And lots of excellent synthetic aperture focusing ultrasound imaging algorithms were listed in this paper. We analyzed the deficiencies and problems of the existing ultrasound focusing algorithms. And we made forecast about the development of synthetic aperture technology in nondestructive testing.
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Durgadevi, P., and S. Vijayalakshmi. "Deep Survey and Comparative Analysis of Medical Image Processing." Journal of Computational and Theoretical Nanoscience 17, no. 5 (May 1, 2020): 2321–29. http://dx.doi.org/10.1166/jctn.2020.8890.
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Biomedical picture handling has encountered emotional extension, and has been an interdisciplinary research field drawing in skill from connected arithmetic, PC sciences, building, insights, material science, science and medication. PC helped indicative handling has just turned into a critical piece of clinical daily schedule. Joined by a surge of new advancement of high innovation and utilization of different imaging modalities, more difficulties emerge; for instance, how to process and dissect a huge volume of pictures so top notch data can be delivered for sickness findings and treatment. The foremost destinations of this course are to give a prologue to essential ideas and strategies for medicinal picture preparing and to advance interests for further examination and research in restorative imaging handling. We will present the Medical Image Processing and abridge related research work here and portray late cutting edge strategies Restorative imaging is regularly seen to assign the arrangement of procedures that noninvasively produce pictures of the inside part of the body. The arrangement of numerical opposite issues has been done with the help of therapeutic imaging. The ultrasonic weight waves and echoes that go inside the tissue to demonstrate the inward structure in medical ultrasonography. In projectional radiography X-beam radiation, which is grouped with respect to its rates and tissue types such as bone, muscle, and fat. As the quality of medical imaging affects analysis that medical image processing has become a vital and the clinical applications wants to store and retrieve images for future purpose needs some suitable process to store those images in details. The paper discusses the general concept of medical image processing.
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Rejani, Sofia, Abdellatif Khamlichi, and Abdellah El-Hajjaji. "Robustness of ultrasonic detection of flaws by using synthetic aperture focusing technique." MATEC Web of Conferences 191 (2018): 00012. http://dx.doi.org/10.1051/matecconf/201819100012.
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One of the challenging problems in non-destructive evaluation is related to identification and sizing of flaws. A high resolution image of the scanned part is required. This allows, through using adequate post-processing of data, to perform localisation and sizing of a flaw. Several techniques have been introduced recently for this purpose. These include among others the synthetic aperture focusing technique, inverse wave-field extrapolation and the total focusing method. However, large uncertainties are affecting the inverse problem solution as provided by these methods when dealing with small defects. It was recognized that reconstruction based on the ultrasonic synthetic aperture focusing technique elaborated in frequency domain provides high resolution imaging even at large distances. This work focused on this promising procedure for the special case of ultrasonic imaging of flaws in 2D elastic medium under plane strain conditions, where the image is provided by a B-scan. Robustness of detection was investigated through perturbing the radargram by white noise and assessed as function of noise energy. It was found that synthetic aperture focusing technique is insensitive to noise.
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Lifshitz, Ilan, Peder C. Pedersen, and Peter A. Lewin. "Reconstruction of the Acoustical Impedance Profile of a Multilayer Medium." Ultrasonic Imaging 14, no. 1 (January 1992): 40–68. http://dx.doi.org/10.1177/016173469201400104.
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The recovery of the acoustical reflectivity function and impedance profile of a layered medium from bandlimited and noisy pulse-echo ultrasonic data is considered. The effects of the transducer and the noise are reduced using Wiener filtering. With further signal processing and a priori knowledge of the attenuation and the velocity profiles, the compensated coefficients of the reflectivity function and the impedance profile are recovered. The reconstruction techniques are presented analytically, and are also evaluated in an experimental setup composed of a conventional pulse echo system, a data acquisition and a data processing system. Under experimental conditions, the RMS errors in the estimation of the compensated acoustical discrete impedance profile were within 3% of the calculated values.
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Mai, Jerome J., Fermin A. Lupotti, and Michael F. Insana. "Vascular Elasticity from Regional Displacement Estimates." Ultrasonic Imaging 25, no. 3 (July 2003): 171–92. http://dx.doi.org/10.1177/016173460302500305.
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A recently-developed ultrasonic technique for measuring elastic properties of vascular tissue is evaluated using computer simulations, phantom and in vivo human measurements. A time sequence of displacement images is measured over the cardiac cycle to describe the spatial and temporal patterns of deformation surrounding arteries. This information is combined with a mathematical model to estimate an elastic modulus. Computer simulations of ultrasonic echo data from deformed tissues are analyzed to define a signal processing approach. Measurements in flow phantoms, with and without vessel-simulating channel walls, provide an assessment of the accuracy and precision of this technique for vascular elasticity measurements. Finally, preliminary results for the stiffness index (β) in a study group of healthy human volunteers are compared with previously reported data. We find that careful measurement technique is required to control measurement variability.
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Jammali, Adel, Afif Belkacem, Kamel Besbes, and Manell E. Zakharia. "Planar synthetic aperture processing (P‐SAS) to real acoustic data of underwater imaging." Journal of the Acoustical Society of America 123, no. 5 (May 2008): 3899. http://dx.doi.org/10.1121/1.2935870.
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Schiefler, Nivaldo, Joaquim Maia, Fabio Schneider, Acácio Zimbico, Amauri Assef, and Eduardo Costa. "Generation and Analysis of Ultrasound Images Using Plane Wave and Sparse Arrays Techniques." Sensors 18, no. 11 (October 28, 2018): 3660. http://dx.doi.org/10.3390/s18113660.
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Ultrasonic imaging is one of the most important techniques to help medical diagnosis. However, obtaining high quality images requires the acquisition, processing, and storage of a large amount of data. In this work, we evaluated a new ultrasound imaging technique based on plane wave and sparse arrays to increase the scan rate and reduce the amount of data amount to be stored. The performance of the proposed method was tested using simulated echo data (from Field II) and phantom data acquired using a Verasonics system equipped with a L11-4v linear array transducer. The tests were done using 128 elements for transmission and 128, 65, 44, and 23 elements sparsely distributed for reception. The simulated data were compared with images obtained with the Delay and Sum (DAS) method and the experimental data were compared with those acquired from Verasonics. The obtained results using the Full Width at Half Maximum (FWHM) criteria at −6 dB showed that the images generated by the proposed method were similar in terms of resolutions (axial and lateral) and contrast to the simulated and the Verasonics commercial ones, indicating that the sparse reception proposed method is suitable for ultrasound imaging.
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Klimonda, Ziemowit, Jerzy Litniewski, Piotr Karwat, and Andrzej Nowicki. "Spatial and Frequency Compounding in Application to Attenuation Estimation in Tissue." Archives of Acoustics 39, no. 4 (March 1, 2015): 519–27. http://dx.doi.org/10.2478/aoa-2014-0056.
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Abstract The soft tissue attenuation is an interesting parameter from medical point of view, because the value of attenuation coefficient is often related to the state of the tissue. Thus, the imaging of the attenuation coefficient distribution within the tissue could be a useful tool for ultrasonic medical diagnosis. The method of attenuation estimation based on tracking of the mean frequency changes in a backscattered signal is presented in this paper. The attenuation estimates are characterized by high variance due to stochastic character of the backscattered ultrasonic signal and some special methods must be added to data processing to improve the resulting images. The following paper presents the application of Spatial Compounding (SC), Frequency Compounding (FC) and the combination of both. The resulting parametric images are compared by means of root-mean-square errors. The results show that combined SC and FC techniques significantly improve the quality and accuracy of parametric images of attenuation distribution.
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Samimi, Kayvan, and Tomy Varghese. "Lower Bound on Estimation Variance of the Ultrasonic Attenuation Coefficient Using the Spectral-Difference Reference-phantom Method." Ultrasonic Imaging 39, no. 3 (October 20, 2016): 151–71. http://dx.doi.org/10.1177/0161734616674329.
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Ultrasonic attenuation is one of the primary parameters of interest in Quantitative Ultrasound (QUS). Non-invasive monitoring of tissue attenuation can provide valuable diagnostic and prognostic information to the physician. The Reference Phantom Method (RPM) was introduced as a way of mitigating some of the system-related effects and biases to facilitate clinical QUS applications. In this paper, under the assumption of diffuse scattering, a probabilistic model of the backscattered signal spectrum is used to derive a theoretical lower bound on the estimation variance of the attenuation coefficient using the Spectral-Difference RPM. The theoretical lower bound is compared to simulated and experimental attenuation estimation statistics in tissue-mimicking (TM) phantoms. Estimation standard deviation (STD) of the sample attenuation in a region of interest (ROI) of the TM phantom is measured for various combinations of processing parameters, including Radio-Frequency (RF) data block length (i.e., window length) from 3 to 17 mm, RF data block width from 10 to 100 A-lines, and number of RF data blocks per attenuation estimation ROI from 3 to 10. In addition to the Spectral-Difference RPM, local attenuation estimation for simulated and experimental data sets was also performed using a modified implementation of the Spectral Fit Method (SFM). Estimation statistics of the SFM are compared to theoretical variance predictions from the literature.1 Measured STD curves are observed to lie above the theoretical lower bound curves, thus experimentally verifying the validity of the derived bounds. This theoretical framework benefits tissue characterization efforts by isolating processing parameter ranges that could provide required precision levels in estimation of the ultrasonic attenuation coefficient using Spectral Difference methods.
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Zhang, Haiyan, Mintao Shao, Guopeng Fan, Hui Zhang, Wenfa Zhu, and Qi Zhu. "Phase Coherence Imaging for Near-Surface Defects in Rails Using Cross-Correlation of Ultrasonic Diffuse Fields." Metals 9, no. 8 (August 8, 2019): 868. http://dx.doi.org/10.3390/met9080868.
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In this paper, phase coherence imaging is proposed to improve spatial resolution and signal-to-noise ratio (SNR) of near-surface defects in rails using cross-correlation of ultrasonic diffuse fields. The direct signals acquired by the phased array are often obscured by nonlinear effects. Thus, the output image processed by conventional post-processing algorithms, like total focus method (TFM), has a blind zone close to the array. To overcome this problem, the diffuse fields, which contain spatial phase correlations, are applied to recover Green’s function. In addition, with the purpose of improving image quality, the Green’s function is further weighted by a special coherent factor, sign coherence factor (SCF), for grating and side lobes suppression. Experiments are conducted on two rails and data acquisition is completed by a commercial 32-element phased array. The quantitative performance comparison of TFM and SCF images is implemented in terms of the array performance indicator (API) and SNR. The results show that the API of SCF is significantly lower than that of TFM. As for SNR, SCF achieved a better SNR than that of TFM. The study in this paper provides an experimental reference for detecting near-surface defects in the rails.
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Blyth, Matthew, Naoki Sakiyama, Hiroshi Hori, Hiroaki Yamamoto, Hiroshi Nakajima, Syed Muhammad Fahim Ud Din, Adam Haecker, and Mark G. Kittridge. "Revealing Hidden Information: High-Resolution Logging-While-Drilling Slowness Measurements and Imaging Using Advanced Dual Ultrasonic Technology." Petrophysics – The SPWLA Journal of Formation Evaluation and Reservoir Description 62, no. 1 (February 1, 2021): 89–108. http://dx.doi.org/10.30632/pjv62n1-2021a6.
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A new logging-while-drilling (LWD) acoustic tool has been developed with novel ultrasonic pitch-catch and pulse-echo technologies. The tool enables both high-resolution slowness and reflectivity images, which cannot be addressed with conventional acoustic logging. Measuring formation elastic-wave properties in complex, finely layered formations is routinely attempted with sonic tools that measure slowness over a receiver array with a length of 2 ft or more depending upon the tool design. These apertures lead to processing results with similar vertical resolutions, obscuring the true slowness of any layering occurring at a finer scale. If any of these layers present significantly different elastic-wave properties than the surrounding rock, then they can play a major role in both wellbore stability and hydraulic fracturing but can be absent from geomechanical models built on routine sonic measurements. Conventional sonic tools operate in the 0.1- to 20-kHz frequency range and can deliver slowness information with approximately 1 ft or more depth of investigation. This is sufficient to investigate the far-field slowness values but makes it very challenging to evaluate the near-wellbore region where tectonic stress redistribution causes pronounced azimuthal slowness variation. This stress-induced slowness variation is important because it is also a key driver of wellbore geomechanics. Moreover, in the presence of highly laminated formations, there can be a significant azimuthal variation of slowness due to layering that is often beyond the resolution of conventional sonic tools due to their operating frequency. Finally, in horizontal wells, multiple layer slownesses are being measured simultaneously because of the depth of investigation of conventional sonic tools. This can cause significant interpretational challenges. To address these challenges, an entirely new design approach was needed. The novel pitch-catch technology operates over a wide frequency range centered at 250 kHz and contains an array of receivers having a 2-in. receiver aperture. The use of dual ultrasonic technology allows the measurement of high-resolution slowness data azimuthally as well as reflectivity and caliper images. The new LWD tool was run in both vertical and horizontal wells and directly compared with both wireline sonic and imaging tools. The inch-scale slownesses obtained show characteristic features that clearly correlate to the formation lithology and structure indicated by the images. These features are completely absent from the conventional sonic data due to its comparatively lower vertical resolution. Slowness images from the tool reflect the formation elastic-wave properties at a fine scale and show dips and lithological variations that are complementary to the data from the pulse-echo images. The physics of the measurement are discussed, along with its ability to measure near-wellbore slowness, elastic-wave properties, and stress variations. Additionally, the effect of the stress-induced, near-wellbore features seen in the slowness images and the pulse-echo images is discussed with the wireline dipole shear anisotropy processing.
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Culshaw, B., S. G. Pierce, and W. J. Staszekski. "Condition monitoring in composite materials: An integrated systems approach." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 212, no. 3 (May 1, 1998): 189–202. http://dx.doi.org/10.1243/0959651981539398.
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This paper presents the results of a collaborative project, the objective of which was to investigate the potential offered by combining ultrasonic Lamb wave interrogation of composite material structures, insonifying the whole structure, with a single wavefront integrating optical fibre detector. The system, which was designed primarily for condition monitoring rather than defect imaging, proved to be capable of detecting small (centimetre square) delaminations, millimetre-sized holes and impact damages of a few joules, all with insonification wavelengths of the order of 2 cm. Data extraction proved to be extremely important since the damage-detection process relies essentially on analysing scattering signatures rather than attempting to image defects and damage. The system—dubbed SISCO (Structurally Integrated Systems for comprehensive evaluation of COmposites)—indicates that self-monitoring structures can be efficiently designed using controlled insonification and a relatively sparse sensor array, presenting a contrast to the more conventional imaging approach involving far more complex sensing arrays and detection and signal processing algorithms.
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Chen, Yuling, Yang Lou, and Jesse Yen. "Dynamic Transmit–Receive Beamforming by Spatial Matched Filtering for Ultrasound Imaging with Plane Wave Transmission." Ultrasonic Imaging 39, no. 4 (March 1, 2017): 207–23. http://dx.doi.org/10.1177/0161734617692017.
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During conventional ultrasound imaging, the need for multiple transmissions for one image and the time of flight for a desired imaging depth limit the frame rate of the system. Using a single plane wave pulse during each transmission followed by parallel receive processing allows for high frame rate imaging. However, image quality is degraded because of the lack of transmit focusing. Beamforming by spatial matched filtering (SMF) is a promising method which focuses ultrasonic energy using spatial filters constructed from the transmit–receive impulse response of the system. Studies by other researchers have shown that SMF beamforming can provide dynamic transmit–receive focusing throughout the field of view. In this paper, we apply SMF beamforming to plane wave transmissions (PWTs) to achieve both dynamic transmit–receive focusing at all imaging depths and high imaging frame rate (>5000 frames per second). We demonstrated the capability of the combined method (PWT + SMF) of achieving two-way focusing mathematically through analysis based on the narrowband Rayleigh–Sommerfeld diffraction theory. Moreover, the broadband performance of PWT + SMF was quantified in terms of lateral resolution and contrast from both computer simulations and experimental data. Results were compared between SMF beamforming and conventional delay-and-sum (DAS) beamforming in both simulations and experiments. At an imaging depth of 40 mm, simulation results showed a 29% lateral resolution improvement and a 160% contrast improvement with PWT + SMF. These improvements were 17% and 48% for experimental data with noise.
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He, Jiaze, Daniel C. Rocha, and Paul Sava. "Guided wave tomography based on least-squares reverse-time migration." Structural Health Monitoring 19, no. 4 (October 19, 2019): 1237–49. http://dx.doi.org/10.1177/1475921719880296.
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A key to successful damage diagnostics and quantification is damage imaging through ultrasonic guided wave tomography. We propose the implementation of least-squares reverse-time migration in a circular array for damage imaging in an aluminum plate. The theory of least-squares reverse-time migration is formulated for guided wave applications along with the summary of an efficient optimization algorithm: the conjugate gradient method. Numerical simulation and laboratory experiments are used to evaluate its performance with a circular array setup. In order to improve the data processing efficiency, the concept of using a limited number of actuators but a relatively large number of sensors is tested. Studies are conducted on three numerical cases, including a rectangular-shaped damage site, a complex-shaped damage site, and six other damage sites varying in size. As an inversion-based method, least-squares reverse-time migration shows significantly improved shape reconstruction with the amplitude quantification capability, compared to conventional reverse-time migration. Our experimental data are generated by piezoelectric wafers as actuators, measured by a scanning laser Doppler vibrometer to form a circular array on an aluminum plate, with a rectangular notch located in the inner region of the array. The damage images using experimental data show consistency in both the simulations using Born scattering and in altered material properties in the damaged region. According to the comparison, least-squares reverse-time migration for guided wave tomography is a promising technology to provide high-resolution large area damage imaging for plate-like structures.
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Rodenacker, Karsten, Klaus Hahn, Gerhard Winkler, and Dorothea P. Auer. "SPATIO-TEMPORAL DATA ANALYSIS WITH NON-LINEAR FILTERS: BRAIN MAPPING WITH fMRI DATA." Image Analysis & Stereology 19, no. 3 (May 3, 2011): 189. http://dx.doi.org/10.5566/ias.v19.p189-194.
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Spatio-temporal digital data from fMRI (functional Magnetic Resonance Imaging) are used to analyse and to model brain activation. To map brain functions, a well-defined sensory activation is offered to a test person and the hemodynamic response to neuronal activity is studied. This so-called BOLD effect in fMRI is typically small and characterised by a very low signal to noise ratio. Hence the activation is repeated and the three dimensional signal (multi-slice 2D) is gathered during relatively long time ranges (3-5 min). From the noisy and distorted spatio-temporal signal the expected response has to be filtered out. Presented methods of spatio-temporal signal processing base on non-linear concepts of data reconstruction and filters of mathematical morphology (e.g. alternating sequential morphological filters). Filters applied are compared by classifications of activations.
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Brandner, Paul A., James A. Venning, and Bryce W. Pearce. "Wavelet analysis techniques in cavitating flows." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2126 (July 9, 2018): 20170242. http://dx.doi.org/10.1098/rsta.2017.0242.
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Cavitating and bubbly flows involve a host of physical phenomena and processes ranging from nucleation, surface and interfacial effects, mass transfer via diffusion and phase change to macroscopic flow physics involving bubble dynamics, turbulent flow interactions and two-phase compressible effects. The complex physics that result from these phenomena and their interactions make for flows that are difficult to investigate and analyse. From an experimental perspective, evolving sensing technology and data processing provide opportunities for gaining new insight and understanding of these complex flows, and the continuous wavelet transform (CWT) is a powerful tool to aid in their elucidation. Five case studies are presented involving many of these phenomena in which the CWT was key to data analysis and interpretation. A diverse set of experiments are presented involving a range of physical and temporal scales and experimental techniques. Bubble turbulent break-up is investigated using hydroacoustics, bubble dynamics and high-speed imaging; microbubbles are sized using light scattering and ultrasonic sensing, and large-scale coherent shedding driven by various mechanisms are analysed using simultaneous high-speed imaging and physical measurement techniques. The experimental set-up, aspect of cavitation being addressed, how the wavelets were applied, their advantages over other techniques and key findings are presented for each case study. This paper is part of the theme issue ‘Redundancy rules: the continuous wavelet transform comes of age’.
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Urosevic, Milovan, Ganesh Bhat, and Marcos Hexsel Grochau. "Targeting nickel sulfide deposits from 3D seismicreflection data at Kambalda, Australia." GEOPHYSICS 77, no. 5 (September 1, 2012): WC123—WC132. http://dx.doi.org/10.1190/geo2011-0514.1.
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The greenstone belts of the Yilgarn Craton, Western Australia, host numerous Archaean gold, nickel, and iron ore deposits. These deposits typically are found in complex geologic structures hidden by a deep, heterogeneous, and often conductive regolith profile. This added complexity limits the depth of penetration for the potential field methods, but at the same time opens new revenue possibilities through the application of seismic methods. To explore this opportunity, we acquired high-resolution, experimental, 3D seismic data over Lake Lefroy in Kambalda, Western Australia. The main objective was to map exceptionally complex, deep structures associated with Kambalda dome. Survey design used 3D ray tracing to improve the distribution of the common reflection points across ultramafic-basalt contacts which host numerous small, high-grade nickel sulfide deposits. A combination of small explosive sources, high-shot/receiver density, and exceptionally good coupling over the ultrasalty lake surface produced seismic data of very high quality. Processing focused on computation of accurate static and dynamic corrections, whereas imaging was helped by the existing geologic model. Advanced volumetric interpretation supported by seismic forward modeling was used to guide mapping of the main lithological interfaces and structures. Forward modeling was carried out using rock properties obtained from ultrasonic measurements and one borehole, drilled in the proximity of the 3D seismic volume. Using this information, geometric constraints based on the typical size of ore bodies found in this mine and a simple window-based seismic attribute, several new targets were proposed. Three of these targets subsequently have been drilled and new zones of mineralization were intercepted. The case study presented demonstrates that high-quality, high-resolution, 3D seismic data combined with volumetric seismic interpretation could become a primary methodology for exploration of deep, small, massive sulfide deposits distributed across the Kambalda area.
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Greenhalgh, Stewart A., Iain M. Mason, and Cvetan Sinadinovski. "In‐mine seismic delineation of mineralization and rock structure." GEOPHYSICS 65, no. 6 (November 2000): 1908–19. http://dx.doi.org/10.1190/1.1444875.
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Significant progress has been made towards the goal of generating detailed seismic images as an aid to mine planning and exploration at the Kambalda nickel mines of Western Australia. Crosshole and vertical‐seismic‐profiling instrumentation, including a slimline multi‐element hydrophone array, three‐component geophone sensors, and a multishot detonator sound source, have been developed along with special seismic imaging software to map rock structure. Seismic trials at the Hunt underground mine established that high frequency (> 1 kHz) signals can be propagated over distances of tens of meters. Tomographic as well as novel 3-D multicomponent reflection imaging procedures have been applied to the data to produce useful pictures of the ore‐stope geometry and host rock. Tomogram interpretation remains problematic because velocity changes not only relate to differing rock types and/or the presence of mineralisation, but can also be caused by alteration/weathering and other rock condition variations. Ultrasonic measurements on rock core samples help in assigning velocity values to lithology, but geological assessment of tomograms remains ambiguous. Reflection imaging is complicated by the presence of strong tube‐wave to body‐wave mode conversion events present in the records, which obscure the weak reflection signatures. Three‐dimensional reflection data processing, especially three‐component analysis, is time consuming and difficult to perform. Notwithstanding the difficulties, the seismic migrations at the Hunt mine show a striking correlation with the known geology. Combined seismic and radar surveying from available underground boreholes and mine drivages is probably needed in the future to more confidently delineate mineralisation.
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Zhang, Qinghui, Yufeng Zhang, Yi Zhou, Kun Zhang, Kexin Zhang, and Lian Gao. "An Ultrasound Simulation Model for the Pulsatile Blood Flow Modulated by the Motion of Stenosed Vessel Wall." BioMed Research International 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/8502873.
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This paper presents an ultrasound simulation model for pulsatile blood flow, modulated by the motion of a stenosed vessel wall. It aims at generating more realistic ultrasonic signals to provide an environment for evaluating ultrasound signal processing and imaging and a framework for investigating the behaviors of blood flow field modulated by wall motion. This model takes into account fluid-structure interaction, blood pulsatility, stenosis of the vessel, and arterial wall movement caused by surrounding tissue’s motion. The axial and radial velocity distributions of blood and the displacement of vessel wall are calculated by solving coupled Navier-Stokes and wall equations. With these obtained values, we made several different phantoms by treating blood and the vessel wall as a group of point scatterers. Then, ultrasound echoed signals from oscillating wall and blood in the axisymmetric stenotic-carotid arteries were computed by ultrasound simulation software, Field II. The results show better consistency with corresponding theoretical values and clinical data and reflect the influence of wall movement on the flow field. It can serve as an effective tool not only for investigating the behavior of blood flow field modulated by wall motion but also for quantitative or qualitative evaluation of new ultrasound imaging technology and estimation method of blood velocity.
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Aref, Mohamed, Ramy Abdlaty, Mohamed Abbass, Ibrahim Aboughaleb, Ayman Nassar, and Abou-Bakr Youssef. "Optical Signature Analysis of Liver Ablation Stages Exploiting Spatio-Spectral Imaging." Journal of Biomedical Photonics & Engineering 7, no. 2 (June 29, 2021): 020306. http://dx.doi.org/10.18287/jbpe21.07.020306.
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Background and Objective: Thermal ablation modalities such as Radiofrequency ablation (RFA) / Microwave ablation (MWA) are deliberately used for marginally invasive tumor removal by escalating tissue temperature. For precise tumor extinguish, thermal ablation outcomes need routine monitoring for tissue necrosis in a challenging research task. The study aims to exploit hyperspectral imaging (HSI) to evaluate the impact of the liver tissue ablation. Materials and Methods: RFA with temperature range (≥80 °C) was accomplished on the ex vivo animal liver and evaluated using a spectral camera (400~1000 nm). The spectral signatures were extracted from the HSI data after the following processing steps: capturing three spectral data cubes for each liver sample with total 7-samples (before ablation, after ablation, and after ablation with sample slicing) using an HSI optical configuration. The custom HSI processing comprises “Top-hat and Bottom-hat transform” combined with “watershed transform” image segmentation to increase the intensity for a region of interest (ROI) of the investigated tissue, linking spectral and spatial data. Additionally, statistical analysis for HSI data was performed to exclusively select the best spectral band that discriminates between the normal, thermally-damaged, and ablated liver regions. Results: The variation of the optical parameters for the investigated liver samples provides variable interaction with the light diffuse reflection (Ŗd) over the spectrum range (400~1000 nm). Where, the extracting spectral information of the various tissue zones from the induced RFA linked to the hemoglobin, methemoglobin, and water permits variations. The generated spectral image after image enhancement utilizing “Top-hat and Bottom-hat transform” followed by “watershed segmentation”, showed high contrast between normal and thermal regions at a wavelength (600 nm). However, the wavelength (900 nm) shows a high variance between the normal and ablated regions. Finally, delineation of the thermal and ablated regions on the complemented enhanced image. Conclusion: HSI is considered a promising optical noninvasive technique for monitoring the RFA toward enhancing the ablation-based treatment for liver tumor outcomes.
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CAITI, ANDREA, MARIA PALMESE, and ANDREA TRUCCO. "RISK ASSESSMENT OF SEAFLOOR WASTE: ACOUSTICAL IMAGING OF BURIED WASTE." Journal of Computational Acoustics 13, no. 02 (June 2005): 385–401. http://dx.doi.org/10.1142/s0218396x05002694.
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This work describes some of the ongoing activities in the framework of the EU-sponsored project SITAR aimed at developing acoustic methods for imaging of waste barrels/containers of small dimension buried in unconsolidated sea sediments. In particular, the work relies on acoustic sub-bottom scattering measurement techniques, with adaptive geometrical configuration of the transmitting/receiving system. The approach ultimately leads to a full 3D measurement of the acoustic scattered field, including bottom and sub-bottom effects, plus the scattering due to buried objects in the scene. The 3D dense acoustic image is then processed in order to automatically extract relevant object(s) features, as size, 3D orientation, impedance contrast; this is obtained through a sequence of processing steps including filtering, enhancement, restoration and image segmentation. Preliminary results obtained with simulative data are presented: data are obtained by modeling the surfaces of both seabed and object(s) as a dense, random grid of discrete scatterers, following the Rayleigh reflection coefficient, and integrating the response of the scatterers. The effects due to absorption and refraction moving from water to sediments are also considered. Sediment volume inhomogeneities are modeled by a random distribution of small asymmetric scattering volumes, characterized by their 3D dimensions, density, and reflection coefficient. A volume growing segmentation approach has been applied, showing efficient segmentation capabilities, and robustness to uncertainty.
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Wang, Bing, Shuncong Zhong, Tung-Lik Lee, Kevin S. Fancey, and Jiawei Mi. "Non-destructive testing and evaluation of composite materials/structures: A state-of-the-art review." Advances in Mechanical Engineering 12, no. 4 (April 2020): 168781402091376. http://dx.doi.org/10.1177/1687814020913761.
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Composite materials/structures are advancing in product efficiency, cost-effectiveness and the development of superior specific properties. There are increasing demands in their applications to load-carrying structures in aerospace, wind turbines, transportation, medical equipment and so on. Thus, robust and reliable non-destructive testing of composites is essential to reduce safety concerns and maintenance costs. There have been various non-destructive testing methods built upon different principles for quality assurance during the whole lifecycle of a composite product. This article reviews the most established non-destructive testing techniques for detection and evaluation of defects/damage evolution in composites. These include acoustic emission, ultrasonic testing, infrared thermography, terahertz testing, shearography, digital image correlation, as well as X-ray and neutron imaging. For each non-destructive testing technique, we cover a brief historical background, principles, standard practices, equipment and facilities used for composite research. We also compare and discuss their benefits and limitations and further summarise their capabilities and applications to composite structures. Each non-destructive testing technique has its own potential and rarely achieves a full-scale diagnosis of structural integrity. Future development of non-destructive testing techniques for composites will be directed towards intelligent and automated inspection systems with high accuracy and efficient data processing capabilities.
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Graves, Edward E., Andrea Pirzkall, Tracy R. Mcknight, Daniel B. Vigneron, David A. Larson, Lynn J. Verhey, Michael Mcdermott, Susan Chang, and Sarah J. Nelson. "USE OF PROTON MAGNETIC RESONANCE SPECTROSCOPIC IMAGING DATA IN PLANNING FOCAL RADIATION THERAPIES FOR BRAIN TUMORS." Image Analysis & Stereology 21, no. 2 (May 3, 2011): 69. http://dx.doi.org/10.5566/ias.v21.p69-76.
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Advances in radiation therapy for malignant neoplasms have produced techniques such as Gamma Knife radiosurgery, capable of delivering an ablative dose to a specific, irregular volume of tissue. However, efficient use of these techniques requires the identification of a target volume that will produce the best therapeutic response while sparing surrounding normal brain tissue. Accomplishing this task using conventional computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) techniques has proven difficult because of the difficulties in identifying the effective tumor margin. Magnetic resonance spectroscopic imaging (MRSI) has been shown to offer a clinically-feasible metabolic assessment of the presence and extent of neoplasm that can complement conventional anatomic imaging. This paper reviews current Gamma Knife protocols and MRSI acquisition, reconstruction, and interpretation techniques, and discusses the motivation for including magnetic resonance spectroscopy findings while planning focal radiation therapies. A treatment selection and planning strategy incorporating MRSI is then proposed, which can be used in the future to assess the efficacy of spectroscopy-based therapy planning.
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Karaman, M., and M. O'Donnell. "Subaperture processing for ultrasonic imaging." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 45, no. 1 (January 1998): 126–35. http://dx.doi.org/10.1109/58.646917.
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Tao, L., X. R. Ma, H. Tian, and Z. X. Guo. "PHASE SUPERPOSITION PROCESSING FOR ULTRASONIC IMAGING." Journal of Sound and Vibration 193, no. 5 (June 1996): 1015–21. http://dx.doi.org/10.1006/jsvi.1996.0328.
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García Nocetti, D. F., J. Solano González, M. F. Valdivieso Casique, R. Ortiz Ramírez, and E. Moreno Hernández. "Parallel Processing in Real-Time Ultrasonic Imaging." IFAC Proceedings Volumes 30, no. 3 (April 1997): 293–97. http://dx.doi.org/10.1016/s1474-6670(17)44506-x.
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Haridasan, G. "Developments of Ultrasonic Imaging and Image Processing." IETE Technical Review 11, no. 1 (January 1994): 37–41. http://dx.doi.org/10.1080/02564602.1994.11437416.
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