Dissertations / Theses: 'Ultrasonic imaging – Data processing'

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Gorfu, Yonael. "Development of a low power ultrasonic data acquisition and imaging system." Thesis, University of Strathclyde, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314583.

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Zhao, Fangwei. "Multiresolution analysis of ultrasound images of the prostate." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0028.

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[Truncated abstract] Transrectal ultrasound (TRUS) has become the urologist’s primary tool for diagnosing and staging prostate cancer due to its real-time and non-invasive nature, low cost, and minimal discomfort. However, the interpretation of a prostate ultrasound image depends critically on the experience and expertise of a urologist and is still difficult and subjective. To overcome the subjective interpretation and facilitate objective diagnosis, computer aided analysis of ultrasound images of the prostate would be very helpful. Computer aided analysis of images may improve diagnostic accuracy by providing a more reproducible interpretation of the images. This thesis is an attempt to address several key elements of computer aided analysis of ultrasound images of the prostate. Specifically, it addresses the following tasks: 1. modelling B-mode ultrasound image formation and statistical properties; 2. reducing ultrasound speckle; and 3. extracting prostate contour. Speckle refers to the granular appearance that compromises the image quality and resolution in optics, synthetic aperture radar (SAR), and ultrasound. Due to the existence of speckle the appearance of a B-mode ultrasound image does not necessarily relate to the internal structure of the object being scanned. A computer simulation of B-mode ultrasound imaging is presented, which not only provides an insight into the nature of speckle, but also a viable test-bed for any ultrasound speckle reduction methods. Motivated by analysis of the statistical properties of the simulated images, the generalised Fisher-Tippett distribution is empirically proposed to analyse statistical properties of ultrasound images of the prostate. A speckle reduction scheme is then presented, which is based on Mallat and Zhong’s dyadic wavelet transform (MZDWT) and modelling statistical properties of the wavelet coefficients and exploiting their inter-scale correlation. Specifically, the squared modulus of the component wavelet coefficients are modelled as a two-state Gamma mixture. Interscale correlation is exploited by taking the harmonic mean of the posterior probability functions, which are derived from the Gamma mixture. This noise reduction scheme is applied to both simulated and real ultrasound images, and its performance is quite satisfactory in that the important features of the original noise corrupted image are preserved while most of the speckle noise is removed successfully. It is also evaluated both qualitatively and quantitatively by comparing it with median, Wiener, and Lee filters, and the results revealed that it surpasses all these filters. A novel contour extraction scheme (CES), which fuses MZDWT and snakes, is proposed on the basis of multiresolution analysis (MRA). Extraction of the prostate contour is placed in a multi-scale framework provided by MZDWT. Specifically, the external potential functions of the snake are designated as the modulus of the wavelet coefficients at different scales, and thus are “switchable”. Such a multi-scale snake, which deforms and migrates from coarse to fine scales, eventually extracts the contour of the prostate

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Wylie, Stephen Robert. "An underwater ultrasonic imaging system." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266220.

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Basoglu, Chris. "A generalized programmable system and efficient algorithms for ultrasound backend processing /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5978.

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曾偉明 and Wai-ming Peter Tsang. "Computer aided ultrasonic flaw detection and characterization." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B31231007.

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Lai, Di. "Independent component analysis (ICA) applied to ultrasound image processing and tissue characterization /." Online version of thesis, 2009. http://hdl.handle.net/1850/11367.

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Brand, Ulrich. "Optical data processing in high-NA imaging." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393167.

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Bañuelos, Saucedo Miguel Angel. "Signal and data processing for THz imaging." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/signal-and-data-processing-for-thz-imaging(58a646f3-033b-4771-b1dc-d1f9fc6dfbf0).html.

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This thesis presents the research made on signal and data processing for THz imaging, with emphasis in noise analysis and tomography in amplitude contrast using a THz time-domain spectrometry system. A THz computerized tomography system was built, tested and characterized. The system is controlled from a personal computer using a program developed ad hoc. Detail is given on the operating principles of the system’s numerous optical and THz components, the design of a computer-based fast lock-in amplifier, the proposal of a local apodization method for reducing spurious oscillations in a THz spectrum, and the use of a parabolic interpolation of integrated signals as a method for estimating THz pulse delay. It is shown that our system can achieve a signal-to-noise ratio of 60 dB in spectrometry tests and 47 dB in tomography tests. Styrofoam phantoms of different shapes and up to 50x60 mm is size are used for analysis. Tomographic images are reconstructed at different frequencies from 0.2 THz to 2.5 THz, showing that volume scattering and edge contrast increase with wavelength. Evidence is given that refractive losses and surface scattering are responsible of high edge contrast in THz tomography images reconstructed in amplitude contrast. A modified Rayleigh roughness factor is proposed to model surface transmission scattering. It is also shown that volume scattering can be modelled by the material’s attenuation coefficient. The use of 4 mm apertures as spatial filters is compared against full beam imaging, and the limitations of Raleigh range are also addressed. It was estimated that for some frequencies between 0.5 THz and 1 THz the Rayleigh range is enough for the tested phantoms. Results on the influence of attenuation and scattering at different THz frequencies can be applied to the development of THz CW imaging systems and as a point of departure for the development of more complex scattering models.

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Rydell, Joakim. "Advanced MRI Data Processing." Doctoral thesis, Linköping : Department of Biomedical Engineering, Linköpings universitet, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10038.

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R, S. Umesh. "Algorithms for processing polarization-rich optical imaging data." Thesis, Indian Institute of Science, 2004. http://hdl.handle.net/2005/96.

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This work mainly focuses on signal processing issues related to continuous-wave, polarization-based direct imaging schemes. Here, we present a mathematical framework to analyze the performance of the Polarization Difference Imaging (PDI) and Polarization Modulation Imaging (PMI). We have considered three visualization parameters, namely, the polarization intensity (PI), Degree of Linear Polarization (DOLP) and polarization orientation (PO) for comparing these schemes. The first two parameters appear frequently in literature, possibly under different names. The last parameter, polarization orientation, has been introduced and elaborated in this thesis. We have also proposed some extensions/alternatives for the existing imaging and processing schemes and analyzed their advantages. Theoretically and through Monte-Carlo simulations, we have studied the performance of these schemes under white and coloured noise conditions, concluding that, in general, the PMI gives better estimates of all the parameters. Experimental results corroborate our theoretical arguments. PMI is shown to give asymptotically efficient estimates of these parameters, whereas PDI is shown to give biased estimates of the first two and is also shown to be incapable of estimating PO. Moreover, it is shown that PDI is a particular case of PMI. The property of PDI, that it can yield estimates at lower variances has been recognized as its major strength. We have also shown that the three visualization parameters can be fused to form a colour image, giving a holistic view of the scene. We report the advantages of analyzing chunks of data and bootstrapped data under various circumstances. Experiments were conducted to image objects through calibrated scattering media and natural media like mist, with successful results. Scattering media prepared with polystyrene microspheres of diameters 2.97m, 0.06m and 0.13m dispersed in water were used in our experiments. An intensified charge coupled device (CCD) camera was used to capture the images. Results showed that imaging could be performed beyond optical thickness of 40, for particles with 0.13m diameter. For larger particles, the depth to which we could image was much lesser. An experiment using an incoherent source yielded better results than with coherent sources, which we attribute to the speckle noise induced by coherent sources. We have suggested a harmonic based imaging scheme, which can perhaps be used when we have a mixture of scattering particles. We have also briefly touched upon the possible post processing that can be performed on the obtained results, and as an example, shown segmentation based on a PO imaging result.

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Chen, Z. "The applications of ultrasonic imaging and signal processing in two-phase flow measurement." Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/10516.

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The applications of ultrasonic imaging and signal processing in two-phase flow measurement have been investigated in this thesis. The scattering by single and many scatterers was studied experimentally and numerically. The statistical properties of the scattered waves from many scatterers were examined and the corresponding results are presented. Ultrasonic transmission/reflection mode tomography was introduced. The theories of reflection mode computerised tomography were developed, by which reflectivity functions and scattering amplitude functions can be reconstructed. Image restoration and interpretation methods are presented. Computer simulation of ultrasonic measurements were carried out. A ultrasonic tomographic imaging system was developed, in which fan-shaped sound beam insonification was employed. Static physical models were used to simulate two-phase flows. In order to speed up the data acquisition of a tomographic imaging system, the single receiver mode and multiple receiver mode data acquisition arrangements were studied by experiments. Experiments on imaging small and large objects were carried out. Several signal and image processing methods were examined. A modified histogram equalisation algorithm was developed for processing the resultant ultrasonic images. The experiment results show that the proposed image reconstruction methods are satisfactory. Possible future developments are proposed.

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Chen, Zhenxiang. "The applications of ultrasonic imaging and signal processing in two-phase flow measurement." Thesis, Cranfield University, 1996. http://dspace.lib.cranfield.ac.uk/handle/1826/10516.

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The applications of ultrasonic imaging and signal processing in two-phase flow measurement have been investigated in this thesis. The scattering by single and many scatterers was studied experimentally and numerically. The statistical properties of the scattered waves from many scatterers were examined and the corresponding results are presented. Ultrasonic transmission/reflection mode tomography was introduced. The theories of reflection mode computerised tomography were developed, by which reflectivity functions and scattering amplitude functions can be reconstructed. Image restoration and interpretation methods are presented. Computer simulation of ultrasonic measurements were carried out. A ultrasonic tomographic imaging system was developed, in which fan-shaped sound beam insonification was employed. Static physical models were used to simulate two-phase flows. In order to speed up the data acquisition of a tomographic imaging system, the single receiver mode and multiple receiver mode data acquisition arrangements were studied by experiments. Experiments on imaging small and large objects were carried out. Several signal and image processing methods were examined. A modified histogram equalisation algorithm was developed for processing the resultant ultrasonic images. The experiment results show that the proposed image reconstruction methods are satisfactory. Possible future developments are proposed.

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Eichert, James J., James F. Carbary, Priscilla L. McKerracher, and Lora L. Suther. "Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) Data Processing Center (DPC)." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/608394.

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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California
The nine sensors and one image processor of the Ultraviolet and Visible Imaging and Spectrographic Imaging (UVISI) instrument aboard the Midcourse Space Experiment (MSX) satellite can potentially generate up to three gigabytes of data of data per day. The UVISI Data Processing Center (DPC) must execute a multitude of complex processing functions in a 24-hour operational window, verify the UVISI data and also provide a compact, quantified record of the verification. The Center additionally must support higher-level data analysis functions. Data processing functions are divided into pipeline processing and data conversion processing. Pipeline processing, which consists of the main pipeline process, Pipeline, and several auxiliary processes is responsible for generating Data Quality Indices (DQI) that summarize sensor performance and Data Measurement Indices (DMI) that summarize sensor measurements. Both sets of indices provide scientists and engineers with a compact, easily-reviewed record of instrument performance. The conversion process, Convert, supports data analysis by converting raw telemetry into scientific/engineering units. On a pixel-by-pixel basis, Convert provides functions for dark-correction, flat-fielding, gain and gate adjustment, non-linearity correction, and count-to-photon conversion. Operating in conjunction with Convert, a pointing utility, Point, is used to determine the locations of selected objects in inertial space. The accomplishment of these myriad tasks relies on a state-of-the-art computer network using multiple workstations. Normal DPC operations are fully automated but remain flexible enough to allow prompt intervention by the UVISI Performance Assessment Team (PAT).

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Zheng, Xing. "Ultrasound image processing and transmission for medical diagnosis /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20ZHENGX.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.
Includes bibliographical references (leaves 66-69). Also available in electronic version. Access restricted to campus users.

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15

Managuli, Ravi A. "Programmable ultrasound color flow system /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6064.

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16

Roy, Simon A. "Data processing pipelines tailored for imaging Fourier-transform spectrometers." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25682/25682.pdf.

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17

Maas, Luis C. (Luis Carlos). "Processing strategies for functional magnetic resonance imaging data sets." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/85262.

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Thesis (Ph.D.)--Harvard--Massachusetts Institute of Technology Division of Health Sciences and Technology, 1999.
Includes bibliographical references (leaves 108-118).
by Luis Carlos Maas, III.
Ph.D.

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18

Gai, Huawen. "Ultrasonic techniques for flow imaging : front-end transducers, image reconstruction algorithms and system design." Thesis, University of Manchester, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387579.

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19

Baiotto, Ricardo. "Imaging methodologies applied on phased array ultrasonic data from austenitic welds and claddings." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/186162.

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A crescente tendência de utilização de materiais austeníticos soldados e cladeados em componentes críticos em alguns setores industriais, como nas indústrias de óleo&gás e nuclear, leva a um aumento na demanda sobre ensaios não-destrutivos confiáveis na avaliação de sua integridade estrutural. Dentre os métodos utilizados na inspeção de soldas cladeados austeníticos estão os métodos de ultrassom por phased array, que são normalmente utilizados na detecção e localização de defeitos. No entanto, componentes com esse tipo de microestrutura são difíceis de inspecionar por phased array devido a anisotropia e inomogeneidade causadas pela microestrutura de grãos grosseiros que costumam levar ao aumento do nível de ruído, ao deslocamento de indicações e ao surgimento de indicações falsas. Sendo assim, a seleção de um método de phased array apropriado precisa levar em conta a habilidade do método em superar os problemas causados pela anisotropia e inomogeneidade. Esta tese apresenta dois métodos de imagem por phased array ultrassônico não-convencionais pensados como formas de ajudar na determinação da integridade de componentes onde soldas e cladeados austeníticos estão presentes. Ambos os métodos tem como base o método de foco total (TFM), sendo que o primeiro é uma extensão do método de leis de atraso adaptativas chamado Método de Foco Total de Atraso Adaptativo (ADTFM) e o segundo método usa fatores de coerência associado à imagens de TFM. A partir dos métodos de imagem aplicados é possível aumentar significativamente a qualidade das imagens por ultrassom em comparação com as imagens padrão obtidas por TFM, especialmente quando foi possível utilizar ambos os métodos combinados.
The increasing trend to use austenitic welded and cladded materials in critical components employed in some industrial sectors, such as the oil&gas and nuclear industries, leads to an increasing demand for their non-destructive assessment by reliable non-destructive methods. Among the methods used to access the integrity of austenitic welds and claddings are the Ultrasonic Phased Array methods, which are usually used to detect the presence and determine the position of defects. However, austenitic welds and claddings are challenging to inspect with Phased Array methods due to the anisotropy and inhomogeneity caused by their coarse grain microstructure, which is capable of increasing noise levels, misplace indications and create false indications. Therefore, the selection of an appropriate phased array method needs to take into account the method’s ability to overcome the impairment caused by anisotropy and inhomogeneity. This thesis presents two non-conventional methods based on ultrasonic phased array imaging techniques designed to assist the structural integrity assessment of components where austenitic welds and clads are present. Both proposed methods are based on the Total Focusing Method (TFM); the first approach is an expansion of the adaptive delay laws concept named Adaptive Delay Total Focusing Method (ADTFM), while the second method uses the coherence weights combined with the TFM images. From the imaging methods applied it was possible to significantly increase the quality of the ultrasonic images in comparison with the standard TFM, primarily when it was possible to combine both approaches.

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Herrmann, Felix J. "Seismic imaging and processing with curvelets." European Association of Geoscientists & Engineers, 2007. http://hdl.handle.net/2429/582.

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Bennett, Michael J. "Signal processing techniques for ultrasonic tissue Doppler and real-time B-mode imaging in cardiology." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/10779.

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Coronary heart disease is the most common cause of death in the UK affecting more than one in five men and one in six women. The cause is generally a constriction of the coronary arteries which supply the heart muscle, or myocardium with blood. In around 95% of cases, the constriction is caused by the process of arteriosclerosis which results in the development of a plaque on the vessel wall. Even though these plaques tend to develop quite slowly, they are sometimes liable to sudden rupture, which causes clotting of the blood in the vessel and hence a sudden reduction in the supply of blood to the myocardium. This thesis is concerned with the signal processing techniques which are used in the form of Doppler Tissue Imaging (DTI) and real-time B-Mode imaging to study the motion of cardiac structures. Although these techniques are well suited to this task, improvements in B-mode contrast resolution and DTI velocity resolution are required if image quality and quantitative measurements are to reach a more acceptable level. Results are presented which demonstrate that the accuracy of the velocity estimations made using DTI can be improved with the use of model based signal processing techniques. The use of the fractional Fourier transform is explored in the context of coded excitation, which is a technique to allow improvements in imaging depth and axial resolution and results are shown which show that this technique is able to offer improvements similar to matched filtering. The combined techniques of empirical mode decomposition and the Hilbert spectrum are used to demonstrate a new interpretation of the physical process underlying non-linear acoustic wave propagation and the existing technique of tissue harmonic imaging.

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Greenaway, Richard Scott. "Image processing and data analysis algorithm for application in haemocytometry." Thesis, University of Hertfordshire, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263063.

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Killingback, Alban Leo Tobias. "Characterisation and data processing for applications of electrical impedance tomography." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389110.

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Tsang, Kwok-hon. "Design of an aperture-domain imaging method and signal acquisition hardware for ultrasound-based vector flow estimation." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572315.

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Hardy, Robert James John. "Problems of imaging the crust in deep water." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335749.

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Weston, Miles. "Advanced ultrasonic digital imaging and signal processing for applications in the field of non-destructive testing." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/advanced-ultrasonic-digital-imaging-and-signal-processing-for-applications-in-the-field-of-nondestructive-testing(12406082-d270-43a0-8520-aed175695115).html.

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Non-destructive testing (NDT) is the process of non-invasive material examination. Within this field, ultrasonic inspection is one method of examination used to detect flaws in structural and functional industrial components, to assess their structural integrity and fitness for service. Conventional NDT ultrasonic array techniques transmit on multiple elements in parallel, according to a focal law, which facilitates beam steering, focussing and scanning within the test component. Received signals are then 'stacked' to generate images of the test component. With the advent of affordable high speed computing, novel data acquisition techniques based on sequential transmission are now able to be developed, which allow images to be generated using advanced signal processing and image reconstruction algorithms. One such data acquisition technique known as Full Matrix Capture (FMC), has received considerable research attention in recent years, largely because it allows fully focused images of test components to be generated. This project provides an improved understanding of the FMC technique and associated signal processing algorithms. It achieves this through the development of novel inspection techniques and signal processing algorithms. Collectively algorithms developed within this work were termed Sequential Phased Array (SPA). Initially comparisons were made between conventional ultrasonic techniques and the SPA algorithms in terms of image quality and speed of inspection. A novel approach was then suggested to facilitate inspection through dual-layered media, separated by a refractive interface using the SPA algorithms. The use of sparse arrays to enhance the speed of inspection using the SPA algorithms was also investigated, and the trade-off between speed of inspection against image degradation was addressed. Finally a novel approach to calibration of a FMC based system was developed, in order to provide uniform image sensitivity during inspection.

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Herrmann, Felix J., Gilles Hennenfent, and Peyman P. Moghaddam. "Seismic imaging and processing with curvelets." European Association of Geoscientists & Engineers, 2007. http://hdl.handle.net/2429/552.

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In this paper, we present a nonlinear curvelet-based sparsity-promoting formulation for three problems in seismic processing and imaging namely, seismic data regularization from data with large percentages of traces missing; seismic amplitude recovery for subsalt images obtained by reverse-time migration and primary-multiple separation, given an inaccurate multiple prediction. We argue why these nonlinear formulations are beneficial.

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Thomas, Seimon M. "Signal and neutral processing techniques for the interpretation of mobile robot ultrasonic range data." Thesis, Cardiff University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246116.

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Zhu, Hui, and 朱暉. "Deformable models and their applications in medical image processing." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31238075.

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Lee, Jae-Min. "Characterization of spatial and temporal brain activation patterns in functional magnetic resonance imaging data." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013024.

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Tsang, Kwok-hon, and 曾國瀚. "Design of an aperture-domain imaging method and signal acquisition hardware for ultrasound-based vector flow estimation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572315.

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Siu, Ka Wai. "Numerical algorithms for data analysis with imaging and financial applications." HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/550.

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In this thesis, we study modellings and numerical algorithms to data analysis with applications to image processing and financial forecast. The thesis is composed of two parts, namely the tensor regression and data assimilation methods for image restoration.;We start with investigating the tensor regression problem in Chapter 2. It is a generalization of a classical regression in order to adopt and analyze much more information by using multi-dimensional arrays. Since the regression problem is subject to multiple solutions, we propose a regularized tensor regression model to the problem. By imposing a low-rank property of the solution and considering the structure of the tensor product, we develop an algorithm which is suitable for scalable implementations. The regularization method is used to select useful solutions which depend on applications. The proposed model is solved by the alternating minimization method and we prove the convergence of the objective function values and iterates by the maximization-minimization (MM) technique. We study different factors which affects the performance of the algorithm, including sample sizes, solution ranks and the noise levels. Applications include image compressing and financial forecast.;In Chapter 3, we apply filtering methods in data assimilation to image restoration problems. Traditionally, data assimilation methods optimally combine a predictive state from a dynamical system with real partially observations. The motivation is to improve the model forecast by real observation. We construct an artificial dynamics to the non-blind deblurring problems. By making use of spatial information of a single image, a span of ensemble members is constructed. A two-stage use of ensemble transform Kalman filter (ETKF) is adopted to deblur corrupted images. The theoretical background of ETKF and the use of artificial dynamics by stage augmentation method are provided. Numerical experiments include image and video processing.;Concluding remarks and discussion on future extensions are included in Chapter 4.

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Tian, Jialin. "Reconstruction of irregularly sampled interferograms in imaging Fourier transform spectrometry." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-06072004-131354/unrestricted/tian%5Fjialin%5F200405%5Fphd.pdf.

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Dhillon, Ravinder. "Diagnostic imaging pathways." University of Western Australia. School of Medicine and Pharmacology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0126.

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[Truncated abstract] Hypothesis: There is deficiency in the evidence base and scientific underpinning of existing diagnostic imaging pathways (DIP) for diagnostic endpoints. Objective: a) To carry out systematic review of literature in relation to use of diagnostic imaging tests for diagnosis and investigation of 78 common clinical problems, b) To identify deficiencies and controversies in existing diagnostic imaging pathways, and to develop a new set of consensus based pathways for diagnostic imaging (DIP) supported by evidence as an education and decision support tool for hospital based doctors and general practitioners, c) To carry out a trial dissemination, implementation and evaluation of DIP. Methods: 78 common clinical presentations were chosen for development of DIP. For general practitioners, clinical topics were selected based on the following criteria: common clinical problem, complex in regards to options available for imaging, subject to inappropriate imaging resulting in unnecessary expenditure and /or radiation exposure, and new options for imaging of which general practitioners may not be aware. For hospital based junior doctors and medical students, additional criteria included: acute presentation when immediate access to expert radiological opinion may be lacking and clinical problem for which there is a need for education. Systematic review of the literature in relation to each of the 78 topics was carried out using Ovid, Pubmed and Cochrane Database of Systematic Reviews. ... The electronic environment and the method of delivery provided a satisfactory medium for dissemination. Getting DIP implemented required vigorous effort. Knowledge of diagnostic imaging and requesting behaviour tended to become more aligned with DIP following a period of intensive marketing. Conclusions: Systematic review of literature and input and feedback from various clinicians and radiologists led to the development of 78 consensus based Diagnostic Imaging Pathways supported by evidence. These pathways are a valuable decision support tool and are a definite step towards incorporating evidence based medicine in patient management. The clinical and academic content of DIP is of practical use to a wide range of clinicians in hospital and general practice settings. It is source of high level knowledge; a reference tool for the latest available and most effective imaging test for a particular clinical problem. In addition, it is an educational tool for medical students, junior doctors, medical imaging technologists, and allied health care personnel.

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Nilsson, Lovisa. "Data-Driven Methods for Sonar Imaging." Thesis, Linköpings universitet, Datorseende, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176249.

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Reconstruction of sonar images is an inverse problem, which is normally solved with model-based methods. These methods may introduce undesired artifacts called angular and range leakage into the reconstruction. In this thesis, a method called Learned Primal-Dual Reconstruction, which combines a data-driven and a model-based approach, is used to investigate the use of data-driven methods for reconstruction within sonar imaging. The method uses primal and dual variables inspired by classical optimization methods where parts are replaced by convolutional neural networks to iteratively find a solution to the reconstruction problem. The network is trained and validated with synthetic data on eight models with different architectures and training parameters. The models are evaluated on measurement data and the results are compared with those from a purely model-based method. Reconstructions performed on synthetic data, where a ground truth image is available, show that it is possible to achieve reconstructions with the data-driven method that have less leakage than reconstructions from the model-based method. For reconstructions performed on measurement data where no ground truth is available, some variants of the learned model achieve a good result with less leakage.

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Farnham, Rodrigo Bouchardet. "Processing and inpainting of sparse data as applied to atomic force microscopy imaging." California State University, Long Beach, 2013.

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Luo, Simon S. "Improved methods of reflection seismic data processing for velocity estimation, imaging, and interpretation." Thesis, Colorado School of Mines, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3668324.

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Seismic images and the geologic information they provide contribute significantly to our understanding of the earth's subsurface. In this thesis, I focus on methods relevant for constructing and interpreting seismic images, including methods for velocity estimation, seismic imaging, and interpretation, which together address key aspects of reflection seismic data processing. Specifically, I propose improved methods for semblance-based normal-moveout velocity analysis, for seismic imaging by least-squares migration, and for the automatic extraction of geologic horizons.

To compute a seismic image, an estimate of the subsurface velocity is needed. One common method for constructing an initial velocity model is semblance-based normal-moveout (NMO) velocity analysis, in which semblance spectra are analyzed to identify peaks in semblance corresponding to effective NMO velocities. The accuracy of NMO velocities obtained from semblance spectra depends on the sensitivity of semblance to changes in velocity. By introducing a weighting function in the semblance calculation, I emphasize terms that are more sensitive to velocity changes, which, as a result, increases the resolution of semblance spectra and allows for more accurate NMO velocity estimates.

Following velocity analysis, a seismic image of the subsurface is computed by migrating the recorded data. However, while velocity analysis is an important step in processing reflection seismic data, in practice we expect errors in the velocity models we compute, and these errors can degrade a seismic image. Instead of minimizing the difference between predicted and observed seismic data as is done for conventional migration, I propose to minimize the difference between predicted and time-shifted observed data, where the time shifts are the traveltime differences between predicted and observed data. With this misfit function, an image computed for an erroneous velocity model contains features similar to those obtained using a more accurate velocity.

Once a seismic image is computed, a common task in interpreting the image is the identification of geologic horizons. As an alternative to manual picking or autotracking, I propose methods to automatically and simultaneously extract all horizons within an image. To extract geologic horizons, a seismic image is unfaulted and unfolded to restore horizons to an undeformed, horizontal state from which they can be easily identified and extracted.

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Barron, Nicholas Henry. "An Analysis of an Advanced Software Business Model for Magnetic Resonance Imaging Data Post Processing." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459422647.

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Kummer, Joseph W. "Signal processing methods to quantify scattering of angle-beam shear waves from through-holes in plates." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54411.

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The objective of this thesis is to present analysis techniques that quantify the scattering of angle-beam ultrasonic waves from through-holes in plates. This topic is of interest because increased understanding of the scattering of ultrasonic waves by a defect is important for the development of many nondestructive evaluation (NDE) applications. Angle-beam techniques are commonly used in industry to detect and characterize defects, and many structures of concern have plate-like components. Scattering from through-holes is particularly important because cracks tend to form around fastener holes, which have high stress concentrations. In addition, varying boundary conditions within a fastener hole can change over the course of a structure’s lifetime and may have significant effects on NDE results. In this research, two signal processing techniques are developed to obtain scattering information from through-holes for a variety of fill conditions, including epoxy and complete and partial filling with metal inserts, using experimentally acquired wavefield measurements. Experimental procedures for acquiring wavefields, which measure the out of plane motion of ultrasonic waves on the surface of a specimen and allow for the visualization and characterization of propagating waves, are presented. Methods for obtaining radial and directional energy maps, which quantify scattering as a function of scattered angle and phase velocity, are described. In addition, baseline subtraction is used to obtain scattering patterns for both methods, which quantify scattering as a function of polar angle for each wave mode present in the wavefield. These techniques are applied to wavefield measurements from through-holes with various fill conditions to investigate the effects of boundary conditions on ultrasonic scattering. A comparison of the radial and directional energy mapping techniques, discussing the strengths and weaknesses of each approach, is provided, and recommendations are made for future work.

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Sukhija, Ruchi. "Document imaging application." CSUSB ScholarWorks, 2007. https://scholarworks.lib.csusb.edu/etd-project/3217.

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The purpose of this project was to develop a document imaging application. By scanning the documents into an electronic repository, medical staff will be able to more easily store and locate these records. To make the application user friendly and facilitate staff access to patient medical records, the application is wed-based and uses the Oracle Application Server to implement a multitiered model.

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Anderson, Shaun David. "Space-time-frequency processing from the analysis of bistatic scattering for simple underwater targets." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45771.

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The development of low-frequency SONAR systems, using a network of autonomous systems in unmanned vehicles, provides a practical means for bistatic measurements (i.e. when the source and receiver are widely separated, thus allowing multiple viewpoints of a target). Furthermore, time-frequency analysis, in particular Wigner-Ville analysis, takes advantage of the evolution of the time dependent echo spectrum to differentiate a man-made target (e.g. an elastic spherical shell, or cylinder) from a natural one of the similar shape (e.g. a rock). Indeed, key energetic features of man-made objects can aid in identification and classification in the presence of clutter and noise. For example, in a fluid-loaded thin spherical shell, an energetic feature is the mid-frequency enhancement echoes (MFE) that result from antisymmetric Lamb waves propagating around the circumference of the shell, which have been shown to be an acoustic feature useful in this pursuit. This research investigates the enhancement and benefits of bistatic measurements using the Wigner-Ville analysis along with acoustic imaging methods. Additionally, the advantage of joint space-time-frequency coherent processing is investigated for optimal array processing to enhance the detection of non-stationary signals across an array. The proposed methodology is tested using both numerical simulations and experimental data for spherical shells and solid cylinders. This research was conducted as part of the Shallow Water Autonomous Mine Sensing Initiative (SWAMSI) sponsored by ONR.

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Vasuki, A. "Diffraction Tomographic Imaging With A Circular Array." Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/119.

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In the conventional diffraction tomography a linear array is used to receive forward scattered field. Then a standard algorithm like back propagation or Fourier domain interpolation is used for reconstruction of the object. A circular array which captures both forward and backward scattered field has been proposed. A new theorem is proposed, which states that the scattered field measured with a large circular array surrounding the object is proportional to the Fourier transform of the object profile taken on the circumference of a circle of radius equa1 to the wave number and centered at (-k0 cosZO, -k0 sin Z0). The circular array outperforms in two counts. Firstly, a larger bandwidth of Fourier transform is used for reconstruction. Secondly, in circular array since the scattered field itself is related to the object Fourier transform, the reconstruction is free from the errors induced by finite array size. The effect of broad band illumination has been studied. A fewer number of illuminations appear to produce a reconstruction which is possible only with a large number of illuminations but narrow band illumination. Thus a trade off between the number of illumination angles and the bandwidth of the source exists.

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van, der Gracht Joseph. "Partially coherent image enhancement by source modification." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/13379.

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Reeves, Stanley J. "A cross-validation approach to image restoration and blur identification." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/13414.

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Gomez, Gonzalez Carlos Alberto, Olivier Wertz, Olivier Absil, Valentin Christiaens, Denis Defrère, Dimitri Mawet, Julien Milli, et al. "VIP: Vortex Image Processing Package for High-contrast Direct Imaging." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624676.

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We present the Vortex Image Processing (VIP) library, a python package dedicated to astronomical high-contrast imaging. Our package relies on the extensive python stack of scientific libraries and aims to provide a flexible framework for high-contrast data and image processing. In this paper, we describe the capabilities of VIP related to processing image sequences acquired using the angular differential imaging (ADI) observing technique. VIP implements functionalities for building high-contrast data processing pipelines, encompassing pre- and post-processing algorithms, potential source. position and flux estimation, and sensitivity curve. generation. Among the reference point-spread. function subtraction techniques for ADI post-processing, VIP includes several flavors of principal component analysis (PCA) based algorithms, such as annular PCA and incremental PCA algorithms capable of processing big datacubes (of several gigabytes) on a computer with limited memory. Also, we present a novel ADI algorithm based on non-negative matrix factorization, which comes from the same family of low-rank matrix approximations as PCA and provides fairly similar results. We showcase the ADI capabilities of the VIP library using a deep sequence on HR 8799 taken with the LBTI/LMIRCam and its recently commissioned L-band vortex coronagraph. Using VIP, we investigated the presence of additional companions around HR 8799 and did not find any significant additional point source beyond the four known planets. VIP is available at http://github. com/vortex-exoplanet/VIP and is accompanied with Jupyter notebook tutorials illustrating the main functionalities of the library.

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McLeish, Kate. "Combining data acquisition and post-processing techniques for magnetic resonance imaging of moving objects." Thesis, King's College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406105.

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Yiu, Yat-shun. "Improving the contrast resolution of synthetic aperture imaging motion artifact reduction based on interleaved data acquisition /." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B4327867X.

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Monnot, Cyril Gerard Valery. "Development of a data analysis platform for characterizing functional connectivity networks in rodents." Thesis, KTH, Skolan för teknik och hälsa (STH), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124391.

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This document addresses the development and implementation of a routine for analyzing resting-state functional Magnetic Resonance Imaging (rs-fMRI) data in rodents. Even though resting-state connectivity is studied in humans already for several years with diverse applications in mental disorders or degenerative brain diseases, the interest for this modality is much more recent and less common in rodents. The goal of this project is to set an ensemble of tools in order to be able for the experimental MR team of KERIC to analyze rs-fMRI in rodents in a well defined and easy way. During this project several critical choices have been done, one of them is to use the Independent Component Analysis (ICA) in order to process the data rather than a seed-based approach. Also it was decided to use medetomidine as anesthesia rather than isoflurane for the experiments. The routine developed during this project was applied for a project studying the effects of running on an animal model of depression. The routine is composed of several steps, the preprocessing of the data mainly realized with SPM8, the processing using GIFT and the postprocessing which is some statistic tests on the results from GIFT in order to reveal differences between groups using the 2nd level analysis from SPM8 and the testing the correlations between components using the FNC toolbox.
Detta dokument behandlar utvecklingen och implementeringen av en rutin för att analysera bilder från resting-state funktionell Magnetisk Resonenstomografi i gnagare. Även om resting-state connectivity studerats i människor i några år, med olika applikationer i psykiska störningar och neurodegenerativa sjukdomar, är intresset för detta område är betydligt nyare bland experimentell förskare som arbetar med gnagare. Målet av denna projekt är att inställa en procedur så att KERICs experimentell MR team kan lätt analysera resting-state funktionnell MRT data. Under denna projekt har olika viktiga val gjorts, en av dem är att använda Independent Component Analysis procedur för att analysera data framför en seed-baserad teknik. En andra var att använda för anestesi medetomidin och inte isofluran för experiment. Rutinen som var utvecklad under denna projekt blev användad på data från en projekt som studerar effekter av löpning på depression hos råttorna. Rutinen är delad i några delar, den första är att förbehandla data främst med SPM8, den andra är att använda GIFT för att behandla data och den sista är att testa statistiskt resultat från ICA med SPM8 och att testa korrelation mellan komponenter med FNC.

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Yiu, Yat-shun, and 姚溢訊. "Improving the contrast resolution of synthetic aperture imaging: motion artifact reduction based oninterleaved data acquisition." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4327867X.

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Chun, Hee. "Auditory sensory feedback tool to supplement visual data perception in radiologic imaging a demonstration using MR mammography /." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1148594830.

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Dissertations / Theses on the topic 'Ultrasonic imaging – Data processing'

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