Dissertations / Theses: 'Image problem'

1

Gilmore, C. J. "The phase problem in crystallography." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321995.

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Dewaal, Nicholas. "The Importance of the Riemann-Hilbert Problem to Solve a Class of Optimal Control Problems." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1759.pdf.

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Xie, Zhifu. "On the N-body Problem." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1444.pdf.

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Yan, Duokui. "Four-body Problem with Collision Singularity." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3111.pdf.

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Grout, Jason Nicholas. "The Minimum Rank Problem Over Finite Fields." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1995.pdf.

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Hessing, Tiffany Marie. "Second Graders' Solution Strategies and Understanding of a Combination Problem." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1470.pdf.

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Robinson, Bruce T. "A multilevel approach to the algebraic image reconstruction problem." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28382.

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Approved for public release; distribution is unlimited
The problem of reconstructing an image from its Radon transform profiles is outlined. This problem has medical, industrial and military applications. Using the computer assisted tomography (CAT) scan as an example, a discretization of the problem based on natural pixels is described, leading to a symmetric linear system that is in general smaller than that resulting from the conventional discretization. The linear algebraic properties of the system matrix are examined, and the convergence of the Gauss-Seidel iteration applied to the linear system is established. Next, multilevel technology is successfully incorporated through a multilevel projection method (PML) formulation of the problem. This results in a V-cycle algorithm, the convergence of which is established. Finally, the problem of spotlight computed tomography, where high quality reconstructions for only a portion of the image are required, is outlined. We establish the formalism necessary to apply fast adaptive composite (FAC) grids in this setting, and formulate the problem in a block Gauss-Seidel form. Numerical results and reconstructed images are presented which demonstrate the usefulness of these two multilevel approaches

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Van, der Heyden Johanna E. "Magnetic resonance image viewing and the screen real estate problem." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ37649.pdf.

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Shao, Wei. "Identifying the shape collapse problem in large deformation image registration." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2276.

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This thesis examines and identifies the problems of shape collapse in large deformation image registration. Shape collapse occurs in image registration when a region in the moving image is transformed into a set of near zero volume in the target image space. Shape collapse may occur when the moving image has a structure that is either missing or does not sufficiently overlap the corresponding structure in the target image. We state that shape collapse is a problem in image registration because it may lead to the following consequences: (1) Incorrect pointwise correspondence between different coordinate systems; (2) Incorrect automatic image segmentation; (3) Loss of functional signal. The above three disadvantages of registration with shape collapse are illustrated in detail using several examples with both real and phantom data. Shape collapse problem is common in image registration algorithms with large degrees of freedom such as many diffeomorphic image registration algorithms. This thesis proposes a shape collapse measurement algorithm to detect the regions of shape collapse after image registration in pairwise and group-wise registrations. We further compute the shape collapse for a whole population of pairwise transformations such as occurs when registering many images to a common atlas coordinate system. Experiments are presented using the SyN diffeomorphic image registration algorithm and diffeomorphic demons algorithm. We show that shape collapse exists in both of the two large deformation registration methods. We demonstrate how changing the input parameters to the SyN registration algorithm can mitigate the collapse image registration artifacts.

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Koy, Andrew B. "Framing the force protection problem : an application of knowledge management /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FKoy.pdf.

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Erken, Ozgur. "A branch-and-bound algorithm for the network diversion problem." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FErken.pdf.

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Thesis (M.S. in Operations Research)--Naval Postgraduate School, December 2002.
Thesis advisor(s): R. Kevin Wood, Matthew Carlyle. Includes bibliographical references (p. 35). Also available online.

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Hudson, Derek Lavell. "Improving Accuracy in Microwave Radiometry via Probability and Inverse Problem Theory." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3244.pdf.

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Raylu, Namrata N. "Testing a cognitive behavioural theory and treatment of problem gambling /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18390.pdf.

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Arceci, Francesca. "Variational algorithms for image Super Resolution." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19509/.

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La Super Resolution è una tecnica che permette di aumentare la risoluzione di un’immagine oltre i limiti imposti dai sensori. Nel processo di acquisizione e formazione dell’immagine, vi sono infatti fenomeni di noise e blurring che la corrompono: da qui l’esigenza di ricostruire l’input reale. Una volta modellizzato questo processo, vi sono svariate tecniche SR che approcciano in modi differenti al problema: in questo lavoro ci basiamo su teniche reconstruction-based che prevedono la minimizzazione di due funzionali, uno che misura la coerenza tra dato e soluzione, l’altro è un termine di regolarizzazione. Lo studio di questa tesi si basa su un’immagine con gradiente sparso, più precisamente un QR code: partendo dalla descrizione del modello matematico, il nostro lavoro sarà quello di trovare un funzionale di regolarizzazione che esprima la proprietà del gradiente sparso e, basandoci sull’approccio dell’ Alternating Direction Method of Multipliers, implementare un nuovo algoritmo che risolva il problema di minimo ad esso associato. Mostreremo i risultati ottenuti confrontandoli con algoritmi preesistenti per provarne la buona performance.

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Mačiulaitytė, Asta. "UAB "Kauno keliai" įvaizdžio valdymas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20130107_164608-53274.

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Išnagrinėti UAB „Kauno keliai“ įvaizdžio formavimą ir valdymą teoriniu bei praktiniu aspektu ir konstatavus įvaizdžio formavimo bei valdymo problemas sukurti įmonės tobulinimo modelį. Teorinėje dalyje analizuojama organizacijos įvaizdžio samprata, kūrimo lygiai, pagrindinai veiksniai, formuojantys organizacijos įvaizdį. Analitinėje baigiamojo darbo dalyje pateikiami ir analizuojami rezultatai, gauti atlikus ir išanalizavus UAB „Kauno keliai“ įvaizdį žiniasklaidoje bei perkančiųjų organizacijų anketinės apklausos tyrimą. Projektinėje darbo dalyje suformuluoti tokie sprendimai: Įvaizdžio formavimo probleminių sričių stiprinimas: teikiamų įmonės paslaugų, parduodamų prekių ir atliekamų darbų įvaizdžio gerinimas, įmonės vardo žinomumo gerinimas, žiniasklaidoje formuojamo įmonės įvaizdžio gerinimas bei vykdomos socialinės veiklos platinimas. Buvo nuspręsta stiprinti įvaizdį formuojančius elementus: personalo įvaizdžio stiprinimas, bei verslo įvaizdžio.
To analyse image formation and management at UAB “Kauno keliai“ from a theoretical and practical perspectives, identify the problems underlying the image formation and management, and suggest a model for the company‘s development. The theoretical part of the thesis presents the concept and stages of the development of company's image and the main factors involved in shaping it. The analytical part of the thesis provides discussion of the results obtained from the analysis of UAB “Kauno keliai” image in the media and the questionnaire survey of contracting organizations.In the project part of the thesis, the following decisions were made: Enhancement of the problematic areas in image formation: improvement of the image of services, goods and works provided by the company; promotion of the positive image of the company’s name; improvement of the company’s image in the media and promotion of the company’s social activity. It was decided to enhance the image of the staff and business image, which are the major image-forming elements.

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Wang, Jianxiong. "A support vector machine approach to a classification problem in robotics /." St. Lucia, Qld, 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17886.pdf.

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Robinson, Martin J. "A logical formulation of the 3D reconstruction problem using volumetric framework /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17245.pdf.

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Travis, Clive Hathaway. "The inverse problem and applications to optical and eddy current imaging." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/804869/.

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Barrus, Michael David. "A forbidden subgraph characterization problem and a minimal-element subset of universal graph classes /." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd374.pdf.

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Neander, David O. "Analysis of temperature variability between Davidson Seamount and Sur Ridge : the tomographic inverse problem." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FNeander.pdf.

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Thompson, Lester. "The indigenous living conditions problem : 'need', policy construction, and potential for change /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18414.pdf.

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Rehman, Tauseef ur. "Efficient numerical method for solution of L² optimal mass transport problem." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33891.

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In this thesis, a novel and efficient numerical method is presented for the computation of the L² optimal mass transport mapping in two and three dimensions. The method uses a direct variational approach. A new projection to the constraint technique has been formulated that can yield a good starting point for the method as well as a second order accurate discretization to the problem. The numerical experiments demonstrate that the algorithm yields accurate results in a relatively small number of iterations that are mesh independent. In the first part of the thesis, the theory and implementation details of the proposed method are presented. These include the reformulation of the Monge-Kantorovich problem using a variational approach and then using a consistent discretization in conjunction with the "discretize-then-optimize" approach to solve the resulting discrete system of differential equations. Advanced numerical methods such as multigrid and adaptive mesh refinement have been employed to solve the linear systems in practical time for even 3D applications. In the second part, the methods efficacy is shown via application to various image processing tasks. These include image registration and morphing. Application of (OMT) to registration is presented in the context of medical imaging and in particular image guided therapy where registration is used to align multiple data sets with each other and with the patient. It is shown that an elastic warping methodology based on the notion of mass transport is quite natural for several medical imaging applications where density can be a key measure of similarity between different data sets e.g. proton density based imagery provided by MR. An application is also presented of the two dimensional optimal mass transport algorithm to compute diffeomorphic correspondence maps between curves for geometric interpolation in an active contour based visual tracking application.

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Pathak, Saurabh. "Quantification Of Internal Droplet Motion Using Particle Image velocimetry For Various Engineering Problem." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1619458988178314.

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Dekdouk, Bachir. "Image reconstruction of low conductivity material distribution using magnetic induction tomography." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/image-reconstruction-of-low-conductivity-material-distribution-using-magnetic-induction-tomography(44d6769d-59b1-44c2-a01e-835f8916f69c).html.

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Magnetic induction tomography (MIT) is a non-invasive, soft field imaging modality that has the potential to map the electrical conductivity (σ) distribution inside an object under investigation. In MIT, a number of exciter and receiver coils are distributed around the periphery of the object. A primary magnetic field is emitted by each exciter, and interacts with the object. This induces eddy currents in the object, which in turn create a secondary field. This latter is coupled to the receiver coils and voltages are induced. An image reconstruction algorithm is then used to infer the conductivity map of the object. In this thesis, the application of MIT for volumetric imaging of objects with low conductivity materials (< 5 Sm-1) and dimensions < 1 m is investigated. In particular, two low conductivity applications are approached: imaging cerebral stroke and imaging the saline water in multiphase flows. In low conductivity applications, the measured signals are small and the spatial sensitivity is critically compromised making the associated inverse problem severely non-linear and ill-posed.The main contribution from this study is to investigate three non-linear optimisation techniques for solving the MIT inverse problem. The first two methods, namely regularised Levenberg Marquardt method and trust region Powell's Dog Leg method, employ damping and trust region strategies respectively. The third method is a modification of the Gauss Newton method and utilises a damping regularisation technique. An optimisation in the convergence and stability of the inverse solution was observed with these methods compared to standard Gauss Newton method. For such non linear treatment, re-evaluation of the forward problem is also required. The forward problem is solved numerically using the impedance method and a weakly coupled field approximation is employed to reduce the computation time and memory requirements. For treating the ill-posedness, different regularisation methods are investigated. Results show that the subspace regularisation technique is suitable for absolute imaging of the stroke in a real head model with synthetic data. Tikhonov based smoothing and edge preserving regularisation methods also produced successful results from simulations of oil/water. However, in a practical setup, still large geometrical and positioning noise causes a major problem and only difference imaging was viable to achieve a reasonable reconstruction.

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Hart, Janelle Marie. "Contextualized Motivation Theory (CMT) : intellectual passion, mathematical need, social responsibility, and personal agency in learning Mathematics /." Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3393.pdf.

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Cipa, Anthony. "The moralization of cigarette smoking in Australia : a new approach to an old problem /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19767.pdf.

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Miflin, Barbara. "Mediating a leap of faith : preparing teachers for problem-based learning in medical education /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16184.pdf.

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Rancie, Elisa M. "An Exploratory Study on the Impact of Applied Ancestry on At-Risk Youth in a Wilderness Therapy Program Setting." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1079.pdf.

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Robison, Diane F. "Active learning in a large enrollment introductory biology class : problem solving, formative feedback, and teaching as learning /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1338.pdf.

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Nie, Jun 1972. "On planar dyads, four-bar linkages and image space insights into the design problem." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81557.

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A planar joint dyad consists of two rigid bodies connected by a P (prismatic) or R (revolute) joint and similarly connected to a fixed third body. The nature of the quadric constraint surface in the planar kinematic mapping image space is investigated. The geometric reasoning concerning why five points in the image space are sufficient to define an RR dyad and why four are enough to define the workspace of a PR or RP dyad is described, explained and exploited.
A general algorithm that combines both type and dimensional design synthesis to the planar joint dyad hence to the five-position Burmester problem in relation to planar four-bar mechanisms is presented. In addition, a special algorithm for the PR or RP dyad type selection is developed. It illustrates that PR or RP dyad can be typed and extracted from the general solutions. Moreover, the conditions under which five given poses admit 0, 2 or 4 real dyad solutions to the Burmester problem are explained.
In this thesis, examples which produce two RR dyad solutions and four dyad ones with various combinations of RR and PR pairs are presented to illustrate that the algorithm can be used to design planar four-bar mechanisms.

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Green, Brian Robert. "Reflections on the circle of life : interactions in a pathology environment (medical) : a 'wicked problem' /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18538.pdf.

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Kimitei, Symon Kipyagwai. "Algorithms for Toeplitz Matrices with Applications to Image Deblurring." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/math_theses/48.

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In this thesis, we present the O(n(log n)^2) superfast linear least squares Schur algorithm (ssschur). The algorithm we will describe illustrates a fast way of solving linear equations or linear least squares problems with low displacement rank. This program is based on the O(n^2) Schur algorithm speeded up via FFT. The algorithm solves a ill-conditioned Toeplitz-like system using Tikhonov regularization. The regularized system is Toeplitz-like of displacement rank 4. We also show the effect of choice of the regularization parameter on the quality of the image reconstructed.

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Kershaw, Helen Elizabeth. "Reconstruction of mechanical properties from surface-based motion data for Digital Image Elasto-Tomography using an implicit surface representation of breast tissue structure." Thesis, University of Canterbury. Mechanical Engineering, 2012. http://hdl.handle.net/10092/7271.

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There has been great interest in recent times in the use of elastography for the characterization of human tissue. Digital Image Elasto-Tomography is a novel breast cancer pre-screening technique under development at the University of Canterbury, which aims to identify and locate stiff areas within the breast that require further investigation using images of the surface motion alone. A calibrated array of five digital cameras is used to capture surface motion of the breast under harmonic actuation. The forward problem, that is the resulting motion for a given mechanical property distribution, is calculated using the Finite Element Method. The inverse problem is to find the mechanical properties which reproduce the measured surface motion through numerical simulation. A reconstruction algorithm is developed using a shape based description to reduce the number of parameters in the inverse problem. A parallel Genetic Algorithm is developed for parameter optimization. A geometric method termed Fitness Function Analysis is shown to improve the inclusion location optimization problem. The ensemble of solutions generated using the Genetic Algorithm is used to produce an optimal and a credible region for inclusion location. Successful single frequency phantom reconstructions are presented. An effective way of combining information from multi-frequency phantom data by examining the characteristics of the measured surface motion using data quality metrics is developed and used to produce improved reconstructions. Results from numerical simulation datasets and a two inclusion phantom used to test the optimization of multiple and ellipsoidal inclusions indicate that although two inclusions can be successfully reconstructed, the single inclusions assumption may suffice even in irregular, heterogeneous cases. This assumption was used to successfully locate the stiffest inclusion in a phantom containing multiple inclusions of differing stiffness based on three multi-frequency datasets. The methods developed in phantoms are applied to three in vivo cases for both single and multi-frequency data with limited success. This thesis builds on previous work undertaken at the University of Canterbury. The original contributions in this work are as follows. A new reconstruction algorithm combining a genetic algorithm with fitness function analysis is developed. The most realistic tissue mimicking phantoms to date are used. An ellipsoidal shape-based description is presented, and applied to the first multi-inclusion reconstructions in DIET. This work presents the first reconstruction using meshes created directly from data using a meshing algorithm developed by Jonas Biehler. A multi-frequency cost function is developed to produce the first multi-frequency and in vivo reconstructions using DIET data.

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Yin, Ke. "New algorithms for solving inverse source problems in imaging techniques with applications in fluorescence tomography." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/48945.

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This thesis is devoted to solving the inverse source problem arising in image reconstruction problems. In general, the solution is non-unique and the problem is severely ill-posed. Therefore, small perturbations, such as the noise in the data, and the modeling error in the forward problem, will cause huge errors in the computations. In practice, the most widely used method to tackle the problem is based on Tikhonov-type regularizations, which minimizes a cost function combining a regularization term and a data fitting term. However, because the two tasks, namely regularization and data fitting, are coupled together in Tikhonov regularization, they are difficult to solve. It happens even if each task can be efficiently solved when they are separate. We propose a method to overcome the major difficulties, namely the non-uniqueness of the solution and noisy data fitting, separately. First we find a particular solution called the orthogonal solution that satisfies the data fitting term. Then we add to it a correction function in the kernel space so that the final solution fulfills the regularization and other physical requirements. The key idea is that the correction function in the kernel has no impact to the data fitting, and the regularization is imposed in a smaller space. Moreover, there is no parameter needed to balance the data fitting and regularization terms. As a case study, we apply the proposed method to Fluorescence Tomography (FT), an emerging imaging technique well known for its ill-posedness and low image resolution in existing reconstruction techniques. We demonstrate by theory and examples that the proposed algorithm can drastically improve the computation speed and the image resolution over existing methods.

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King-Peery, Karolyn. "Matthew's gift : teaching parents of children with disabilities to deal effectively with their child's problem behavior / y Karolyn King-Peery." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd772.pdf.

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Maddukuri, Achyutha Ramarao. "Fractional Fourier Transform and Scaling Problem in Signals and Images." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16985.

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Context: We identify a material or thing that can be seen and touched in the world as having structures at both coarser and finer levels of scale. Scaling problem presents in a branch of science concerned with the description, prediction understanding of natural phenomena and visual arts. A moon, for instance, may appear as having a roughly round shape is much larger than stars when seen from the earth. In the closer look, the moon is much smaller than the stars. The fact that objects in the world appear in different ways depending upon the scale of observation has important implications when analyzing measured data, such as images, with automatic methods [1]. The type of information we are seeking from a one-dimensional signal or two-dimensional image is only possible when we have the right amount of scale for the structure of an image or signal data. In many modern applications, the right scale need not be obvious at all, and we all need a complete mathematical analysis on this scaling problem. This thesis is shown how a mathematical theory is formulated when data or signal is describing at different scales. Objectives: The subtle patterns deforming in data that can foretell of a scaling problem? The main objectives of this thesis are to address the dynamic scaling pattern problem in computers and study the different methods, described in the latest issue of Science, are designed to identify the patterns in data. Method: The research methodology used in this thesis is the Fractional Fourier Transform. To recognize the pattern for a different level of scale to one or many components, we take the position and size of the object and perform the transform operation in any transform angle and deform the component by changing to another angle which influences the frequency, phase, and magnitude. Results: We show that manipulation of Fractional Fourier transform can be used as a pattern recognition system. The introduced model has the flexibility to encode patterns to both time and frequency domain. We present a detailed structure of a dynamic pattern scaling problem. Furthermore, we show successful recognition results even though one or many components deformed to different levels using one-dimensional and two-dimensional patterns. Conclusions: The proposed algorithm FrFT has shown some advantages over traditional FFT due to its competitive performance in studying the pattern changes. This research work investigated that simulating the dynamic pattern scaling problem using FrFT. The Fractional Fourier transform does not do the scaling. Manipulating the Fractional Fourier transform can be helpful in perceiving the pattern changes. We cannot control the deformation but changing the parameters allow us to see what is happening in time and frequency domain.

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Peters, Ashton. "Digital Image Elasto-Tomography: Mechanical Property Reconstruction from Surface Measured Displacement Data." Thesis, University of Canterbury. Department of Mechanical Engineering, 2007. http://hdl.handle.net/10092/2775.

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Interest in elastographic techniques for soft tissue imaging has grown as relevant research continues to indicate a correlation between tissue histology and mechanical stiffness. Digital Image Elasto-Tomography (DIET) presents a novel method for identifying cancerous lesions via a three-dimensional image of elastic properties. Stiffness reconstruction with DIET takes steady-state motion captured with a digital camera array as the input to an elastic property reconstruction algorithm, where finite element methods allow simulation of phantom motion at a range of internal stiffness distributions. The low cost and high image contrast achievable with a DIET system may be particularly suited to breast cancer screening, where traditional modalities such as mammography have issues with limited sensitivity and patient discomfort. Proof of concept studies performed on simulated data sets confirmed the potential of the DIET technique, leading to the development of an experimental apparatus for surface motion capture from a range of soft tissue approximating phantoms. Error studies performed on experimental data from these phantoms using a limited number of shape and modulus parameters indicated that accurate measurements of surface motion provide sufficient information to identify a stiffness distribution in both homogeneous and heterogeneous cases. The elastic reconstruction performed on simulated and experimental data considered both deterministic and stochastic algorithms, with a combination of the two approaches found to give the most accurate results, for a realistic increase in computational cost. The reconstruction algorithm developed has the ability to successfully resolve a hard spherical inclusion within a soft phantom, and in addition demonstrated promise in reconstructing the correct stiffness distribution when no inclusion is present.

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Arp, Melanie K. "The frequency and severity of problem behaviors among individuals with autism, traumatic brain injury, and mental retardation from the Utah DSPD dataset /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1050.pdf.

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Wang, Li. "Fast and Accurate 3D X ray Image Reconstruction for Non Destructive Test Industrial Applications." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS362/document.

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La tomographie en 2D et 3D sont largement utilisée dans l’imagerie médicale ainsi que dans le Contrôle Non Destructif (CND) pour l’industrie. Dans toutes les deux applications, il est nécessaire de réduire le nombre de projections. Dans certains cas, la reconstruction doit être faite avec un nombre d’angle de projections limité. Les données mesurées sont toujours avec des erreurs (erreurs de mesure et de modélisation). Nous sommes donc presque toujours dans la situation de problèmes inversés mal posés. Le rôle des méthodes probabilistes et de la modélisation a priori devient crucial. Pour la modélisation a priori, en particulier dans les applications NDT, l’objet à l’examen est composé de plusieurs matériaux homogènes, avec plusieurs blocs continus séparés par des discontinuités et des contours. Ce type d’objet est dit continu par morceaux. L’objet de cette thèse est sur la reconstruction des objets continu ou constante par morceaux, ou plus généralement homogène par morceaux. En résumé, deux méthodes principales sont proposées dans le contexte de l’inférence bayésienne. La première méthode consiste à reconstruire l’objet en imposant que sa transformée de Haar soit parcimonieuse. Un modèle bayésien hiérarchique est proposé. Dans cette méthode, les variables et les paramètres sont estimés et les hyper-paramètres sont initialisés selon la définition des modèles antérieurs. La deuxième méthode reconstruit les objets en estimant simultanément les contours. L’objet continu par morceaux est modélisé par un modèle markovien non-homogène, qui dépend du gradient de l’objet, et le gradient dépend aussi de l’estimation de l’objet. Cette méthode est également semi-supervisé, avec les paramètres estimés automatiquement. Ces méthodes sont adaptées aux reconstructions de grande taille de données 3D, dans lesquelles le processeur GPU est utilisé pour accélérer les calculs. Les méthodes sont validées avec des données simulées et des données réelles, et sont comparées avec plusieurs méthodes classiques
2D and 3D X-ray Computed Tomography (CT) is widely used in medical imaging as well as in Non Destructive Testing (NDT) for industrial applications. In both domains, there is a need to reduce the number of projections. In some cases we may also be limited in angles. The measured data are always with errors (measurement and modelling errors). We are consequently almost always in the situation of ill-posed inverse problems. The role of the probabilistic methods and the prior modelling become crucial. For prior modelling, in particular in NDT applications, the object under examination is composed with several homogeneous materials, with several continuous blocs separated by some discontinuities and contours. This type of object is called the piecewise-continuous object. The focus of this thesis on the reconstruction of the picewise continuous or constant, or more generally piecewise homogeneous objects. In summary two main methods are proposed in the context of the Bayesian inference. The first method consists in reconstructing the object while enforcing the sparsity of the discrete Haar transformation coefficients of the object. A hierarchical Bayesian model is proposed. In this method, the unknown variables and parameters are estimated and the hyper-parameters are initialized according to the definition of prior models. The second method reconstruct objects while the contours are estimated simultaneously. The piecewise continuous object is modeled by a non-homogeneous Markovian model, which depends on the gradient of the object, while the gradient also depends on the estimation of the object. In this methods, the semi-supervised system model is also achieved, with the parameters estimated automatically. Both methods are adapted to the 3D big data size reconstructions, in which the GPU processor is used to accelerate the computation. The methods are validated with both simulated and real data, and are compared with several conventional state-of-the-art methods

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Cunial, Kimberley Jane. "Developing an instrument for measuring teachers' reactive-proactive responses to disruptive behaviour in educational settings /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19788.pdf.

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Money, James H. "Variational methods for image deblurring and discretized Picard's method." Lexington, Ky. : [University of Kentucky Libraries], 2006. http://lib.uky.edu/ETD/ukymath2006d00415/DISSERT.PDF.

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Thesis (Ph. D.)--University of Kentucky, 2006.
Title from document title page (viewed on May 31, 2006). Document formatted into pages; contains x, 97 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 90-96).

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Trembath, Mark. "Detection of substance misuse in people with a psychotic disorder : preliminary analysis of the problem list as a new screening measure /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18764.pdf.

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Xiao, Bo. "Parallel algorithms for generalized N-body problem in high dimensions and their applications for bayesian inference and image analysis." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53052.

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In this dissertation, we explore parallel algorithms for general N-Body problems in high dimensions, and their applications in machine learning and image analysis on distributed infrastructures. In the first part of this work, we proposed and developed a set of basic tools built on top of Message Passing Interface and OpenMP for massively parallel nearest neighbors search. In particular, we present a distributed tree structure to index data in arbitrary number of dimensions, and a novel algorithm that eliminate the need for collective coordinate exchanges during tree construction. To the best of our knowledge, our nearest neighbors package is the first attempt that scales to millions of cores in up to a thousand dimensions. Based on our nearest neighbors search algorithms, we present "ASKIT", a parallel fast kernel summation tree code with a new near-far field decomposition and a new compact representation for the far field. Specially our algorithm is kernel independent. The efficiency of new near far decomposition depends only on the intrinsic dimensionality of data, and the new far field representation only relies on the rand of sub-blocks of the kernel matrix. In the second part, we developed a Bayesian inference framework and a variational formulation for a MAP estimation of the label field for medical image segmentation. In particular, we propose new representations for both likelihood probability and prior probability functions, as well as their fast calculation. Then a parallel matrix free optimization algorithm is given to solve the MAP estimation. Our new prior function is suitable for lots of spatial inverse problems. Experimental results show our framework is robust to noise, variations of shapes and artifacts.

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Sahin, Ferat. "A Radial Basis Function Approach to a Color Image Classification Problem in a Real Time Industrial Application." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36847.

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In this thesis, we introduce a radial basis function network approach to solve a color image classification problem in a real time industrial application. Radial basis function networks are employed to classify the images of finished wooden parts in terms of their color and species. Other classification methods are also examined in this work. The minimum distance classifiers are presented since they have been employed by the previous research. We give brief definitions about color space, color texture, color quantization, color classification methods. We also give an intensive review of radial basis functions, regularization theory, regularized radial basis function networks, and generalized radial basis function networks. The centers of the radial basis functions are calculated by the k-means clustering algorithm. We examine the k-means algorithm in terms of starting criteria, the movement rule, and the updating rule. The dilations of the radial basis functions are calculated using a statistical method. Learning classifier systems are also employed to solve the same classification problem. Learning classifier systems learn the training samples completely whereas they are not successful to classify the test samples. Finally, we present some simulation results for both radial basis function network method and learning classifier systems method. A comparison is given between the results of each method. The results show that the best classification method examined in this work is the radial basis function network method.
Master of Science

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Rosato, Matthew J. "Applying conformal mapping to the vertex correspondence problem for 3D face models." Diss., Online access via UMI:, 2007.

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Bernardini, Stefano. "Regularization methods for the solution of a nonlinear least-squares problem in tomography." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8975/.

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In this work we study a polyenergetic and multimaterial model for the breast image reconstruction in Digital Tomosynthesis, taking into consideration the variety of the materials forming the object and the polyenergetic nature of the X-rays beam. The modelling of the problem leads to the resolution of a high-dimensional nonlinear least-squares problem that, due to its nature of inverse ill-posed problem, needs some kind of regularization. We test two main classes of methods: the Levenberg-Marquardt method (together with the Conjugate Gradient method for the computation of the descent direction) and two limited-memory BFGS-like methods (L-BFGS). We perform some experiments for different values of the regularization parameter (constant or varying at each iteration), tolerances and stop conditions. Finally, we analyse the performance of the several methods comparing relative errors, iterations number, times and the qualities of the reconstructed images.

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Dalling, Ryan R. "An Investigation of Positive Engagement, Continuously Variable Transmissions." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2391.pdf.

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McDonald, Jason K. "Technology I, II, and III : criteria for understanding and improving the practice of instructional technology /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1610.pdf.

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Bechensteen, Arne. "Optimisation L2-L0 contrainte et application à la microscopie à molécule unique." Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4068.

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L'optimisation parcimonieuse est cruciale dans la société d'aujourd'hui, car elle est utilisée dans de nombreux domaines, tels que le débruitage, la compression, l’apprentissage et la sélection de caractéristiques. Cependant, obtenir une bonne solution parcimonieuse d'un signal est un défi de calcul.Cette thèse se concentre sur l'optimisation d’un terme des moindres carrés en norme L0 sous une contrainte de k-parcimonie sur la solution exprimée avec la pseudo-norme L0 (le problème L2-L0 contraint). Nous étudions également la somme de la fonction de perte des moindres carrés et d'un terme de pénalité L0 (le problème L2-L0 pénalisé). Les deux problèmes sont non convexes, non continus et NP-durs. Nous proposons trois nouvelles approches d'optimisation parcimonieuse. Nous présentons d'abord une relaxation continue du problème contraint et présentons une méthode pour minimiser la relaxation proposée. Deuxièmement, nous reformulons la pseudo-norme L0 comme un problème de minimisation convexe. Ceci est fait en introduisant une variable auxiliaire, et nous présentons une reformulation exacte du problème contraint (CoBic) et pénalisé (PeBic). Enfin, nous présentons une méthode pour minimiser le produit du terme de fidélité des données et du terme de régularisation. Ce dernier est un travail de recherche en cours. Nous appliquons les trois premières méthodes proposées (relaxation, CoBic et PeBic) à la microscopie par molécule unique. Les résultats des algorithmes proposés sont à l'état de l'art des méthodes basées sur la grille. De plus, fixer la constante de contrainte de parcimonie est généralement plus intuitif que fixer le paramètre de pénalité, ce qui rend l’approche contrainte attractive pour les applications
Sparse optimization is crucial in today's society, as this is used in multiple domains, such as denoising, compression, machine learning, and variable selection. Sparse optimization is also vital in single-molecule localization microscopy, a microscopy method widely used in biology. However, obtaining a good sparse solution of a signal is computationally challenging. This thesis focuses on sparse optimization in the form of minimizing the least square loss function under a k-sparse constraint with an L0 pseudo-norm (the constrained L2-L0 problem). We also study the sum of the least square loss function and an L0 penalty term (the penalized L2-L0 problem). Both problems are non-convex, non-continuous, and NP-hard. We propose three new approaches to sparse optimization. We present first a continuous relaxation of the constrained problem and present a method to minimize the proposed relaxation. Secondly, we reformulate the L0 pseudo-norm as a convex minimization problem. This is done by introducing an auxiliary variable, and we present an exact biconvex reformulation of the constrained (CoBic) and penalized (PeBic) problems. Finally, we present a method to minimize the product of the data fidelity term and the regularization term. The latter is still an ongoing research work. We apply the three proposed methods (relaxation, CoBic, and PeBic) to single-molecule localization microscopy and compare them with other commonly used algorithms in sparse optimization. The proposed algorithms' results are as good as the state-of-the-art in grid-based methods. Furthermore, fixing the sparsity constraint constant is usually more intuitive than fixing the penalty parameter, making the constraint approach attractive for applications

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Werbeck, Kai-Uwe Langston Richard. "The interface as door on the problem of access to the image in Kafka's Das Schloss and interactive media /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1706.

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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2008.
Title from electronic title page (viewed Sep. 16, 2008). "... in partial fulfillment of the requirements for the degree of Master of Arts in the department of Germanic Languages and Literatures." Discipline: Germanic Languages; Department/School: Germanic Languages.

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Dissertations / Theses on the topic 'Image problem'

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