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Goodenow, Daniel P. "A reference guide to JPEG compression /." Online version of thesis, 1993. http://hdl.handle.net/1850/11714.
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Dean, Chad E. Vosters Nathan P. "Update of the Navy Contract Writing Guide /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FDean%5FMBA.pdf.
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Thesis (M.B.A.)--Naval Postgraduate School, December 2003.<br>"MBA professional report"--Cover. Thesis advisor(s): E. Marshall Engelbeck, Jeffrey Cuskey. Includes bibliographical references (p. 19-22). Also available online.
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Al-Zoubi, Asem S. "Rectangular dielectric resonator antennas fed by dielectric image guide /." Full text available from ProQuest UM Digital Dissertations, 2008. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1799142881&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1257878793&clientId=22256.
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Thesis (Ph.D.)--University of Mississippi, 2008.<br>Typescript. Vita. "December 2008." Dissertation director: Ahmed A. Kishk Includes bibliographical references (leaves 142-148). Also available online via ProQuest to authorized users.
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Dobbs, Andrew L. "A program manager's guide for software cost estimating." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FDobbs.pdf.
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Ko, Eunbyol. "Music and Image a performer's guide to Maurice Ravel's Miroirs /." Cincinnati, Ohio : University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1172781745.
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Thesis (Dr. of Musical Arts)--University of Cincinnati, 2007.<br>Title from electronic thesis title page (viewed Apr.3, 2007). Includes abstract. Keywords: Ravel; Miroirs; Performer's Guide; Image; Impressionism; Symbolism; Eunbyol Ko Includes bibliographical references.
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Isbel, Joanne. ""The good friend guide" : a group social skills intervention /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18047.pdf.
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Paul, Dominique-Lynda. "Contribution à la modélisation des principaux éléments passifs en technologie guide image." Brest, 1990. http://www.theses.fr/1990BRES2002.
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Ce travail a pour objet l'etude et la modelisation des elements passifs de base intervenant dans la realisation de filtres en technologie guide image. Ainsi, apres avoir examine les approches actuellement disponibles concernant cette structure, l'auteur s'est interesse a la modelisation de resonateurs annulaires fonctionnant en modes hybrides d'ordres azimutaux eleves et plus particulierement au probleme du couplage entre ces deux structures. Si les modeles utilises concordent tres bien avec l'experience dans la bande basse des hyperfrequences (bande x), l'etude experimentale en ondes millimetriques a montre leur imprecision relative. La derniere section a donc objet de proposer quelques ameliorations a apporter a ces approches ouvrant ainsi la voie a des travaux futurs
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Ko, Eunbyol. "Music and Image: A Performer’s Guide to Maurice Ravel’s Miroirs." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1172781745.
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Toutain, Serge. "Contribution à l'étude du guide image mise en évidence d'ondes à fuites." Lille 1, 1986. http://www.theses.fr/1986LIL10157.
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Etude critique des différentes approches théoriques et proposition d'un nouveau modèle base sur la caractérisation de discontinuités en guide ouvert en association avec la méthode de la résonance transverse. Cette méthode montre la possibilité de création d'ondes de fuite et explicite les limitations d'utilisation liées à ce phénomène. Etude de sous-ensembles tels que coupleurs de proximité et résonateurs diélectriques tubulaires
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Toutain, Serge. "Contribution à l'étude du guide image mise en évidence d'ondes à fuites /." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37601616n.
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Reyt, Ida. "Écoulements induits en guide d'onde acoustique fort niveau." Thesis, Poitiers, 2012. http://www.theses.fr/2012POIT2292/document.
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La propagation d'une onde acoustique en guide est associée, pour de forts niveaux, à un certain nombre de phénomènes de l'acoustique non linéaire. Parmi ces phénomènes, les écoulements redressés (ou vent acoustique), l'effet d'une discontinuité et la transition à la turbulence, à l'étude dans ce mémoire, sont associés à la génération d'écoulements induits. L'étude expérimentale de ces phénomènes repose sur l'adaptation des méthodes de vélocimétrie Laser : Vélocimétrie Laser par effet Doppler (VLD) et Vélocimétrie par Images de Particules (PIV) à la mesure des différents écoulements. Ainsi, des mesures PIV en sortie de convergent, viennent compléter des mesures VLD réalisées antérieurement. Dans l'espoir de mieux appréhender les spécificités de la transition à la turbulence en guide d'onde acoustique, l'évolution de la couche limite de Stokes est étudiée pour des amplitudes de vitesse acoustique croissantes. Une étude expérimentale des écoulements redressés dans un guide d'onde à section carrée est proposée et les spécificités liées à cette géométrie sont recherchées. En outre, l'évolution des tourbillons du vent acoustique en guide d'onde cylindrique est analysée lorsque le vent devient rapide et certains facteurs pouvant être à l'origine de cette évolution sont modifiés. La répartition harmonique dans le guide est ainsi modifiée, puis l'influence des conditions thermiques est abordée en couplant les mesures de vitesses à des mesures de température moyenne dans le guide et en paroi. Une comparaison avec des résultats issus de simulations numériques permet de conforter l'évolution des écoulements redressés observée<br>High amplitude acoustic propagation in a guide is associated with several non linear phenomena including acoustic streaming, discontinuity effects and transition to turbulence. Those phenomena are studied in this work and are all associated with acoustically induced flows. The present experimental study therefore is based on velocimetry laser techniques: Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV), wich are fitted to the measurement of the different flow velocity components. Firstly, PIV measurements at the exit of a convergent enable to complement previous LDV measurements. Then, in order to a better understanding of the specificity of transition to turbulence in acoustics, the evolution of the Stokes boundary layer is studied for increasing acoustic velocity amplitudes. Then an experimental study of acoustic streaming in a square channel is reported, and the influence of the geometry is examined. Moreover, the evolution of acoustic streaming vortices in a cylindrical waveguide is analyzed for fast streaming and some parameters that could control such evolution are modified. The harmonicdistribution inside the guide is changed and then the influence of thermal conditions is studied by coupling velocity measurements and mean temperature measurements inside the waveguide and along the wall. Some comparisons between measured streaming velocities and numerical simulation results are presented
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Larsson, Mathias. "Machine vision for finding a joint to guide a welding robot." Thesis, University West, Department of Engineering Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-1783.
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<p>This report contains a description on how it is possible to guide a robot along an edge, by using a camera mounted on the robot. If stereo matching is used to calculate 3Dcoordinates of an object or an edge, it requires two images from different known positions and orientations to calculate where it is. In the image analysis in this project, the Canny edge filter has been used. The result from the filter is not useful directly, because it finds too many edges and it misses some pixels. The Canny edge result must be sorted and finally filled up before the final calculations can be started. This additional work with the image decreases unfortunately the accuracy in the calculations. The accuracy is estimated through comparison between measured coordinates of the edge using a coordinate measuring machine and the calculated coordinates. There is a deviation of up to three mm in the calculated edge. The camera calibration has been described in earlier thesis so it is not mentioned in this report, although it is a prerequisite of this project.</p>
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Paquette, Maxime. "La représentation du guide national en France et en Allemagne les cas de Napoléon Bonaparte et d'Adolf Hitler." Mémoire, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/5702.
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À travers ce mémoire, nous avons tenté de répondre à la problématique suivante : comment Napoléon Bonaparte et Adolf Hitler ont-ils organisé leur image de dirigeant et de guide de la nation, et ce, dans quels buts? Nous avons formulé notre réponse selon notre opinion, c'est-à-dire que le guide national est un vecteur identitaire qui mélange le culte de la personnalité, les symboles du pouvoir et le nationalisme. Pour saisir tous les aspects que comprend cette réponse, il nous faut inévitablement faire appel à la propagande qui joue un rôle prédominant dans l'opinion publique française et allemande de ces époques. Ainsi, notre réponse s'articule en quatre parties. En premier lieu, nous constatons que c'est à travers la théorie des deux corps du roi que Napoléon et Hitler ont fusionné l'Ancien et le Moderne à leur personne. Ils ont ainsi tenté de se rallier leur peuple en invoquant le spirituel et en prétendant à une intervention divine pour justifier leur position. En second lieu, afin d'accentuer l'aspect d'intervention providentielle, Napoléon et Hitler sont représentés comme étant, en quelque sorte, des messies destinés à diriger leur nation vers un avenir plus radieux. Pour légitimer cette position, ils reprennent une série de référents à la chrétienté. En troisième lieu, nous verrons que les guides, afin de marquer leur position de pouvoir, exploitent le passé de la nation. Que ce soit dans les peintures ou dans les affiches de propagande, il est possible de constater la frappante similarité des symboles utilisés par Napoléon et Hitler. Dans les deux cas, le guide national semble être reproduit selon un schème de pensée semblable. En quatrième lieu, nous démontrons, par l'entremise des théories de Walter Benjamin et d'Antonio Gramsci, comment l'art et certains moyens de communication sont dénaturalisés sous Napoléon et Hitler afin de servir non pas de force artistique, mais de propagande. Nous exposons que le télégraphe de Chappe, la radio, le théâtre et le cinéma sont des outils de premier choix pour servir les propos politiques de Napoléon et d'Hitler. En définitive, notre mémoire constitue une contribution historiographique à un champ peu exploité et négligé. Le rapprochement entre Napoléon et Hitler nous permet de mieux cerner le pouvoir et ce qui l'entoure, de même que la puissance de la propagande et du nationalisme combinée au concept de guide national.
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Iturbe, Ion. "Tomographie acoustique haute résolution dans un guide d'onde océanique." Phd thesis, Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00521540.
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Cette thèse porte sur la Tomographie Acoustique Océanique qui permet d'estimer la température de l'eau dans une tranche d'océan à partir de mesures acoustiques. Les vitesse de propagation des ondes étant fortement liée à la température, la tomographie consiste à estimer la célérité à partir des mesures des temps de propagation des ondes acoustiques. Nous nous intéressons à des acquisitions réalisées avec deux antennes, une d'émetteurs et une de récepteurs, placées verticalement face à face, dans un guide d'ondes côtier. Dans ces guides peu profonds, la mesure des temps de propagation ainsi que leur identification sont difficiles à réaliser à cause de la propagation multi-trajets. Avec une acquisition à deux antennes, nous proposons un algorithme de Double Formation de Voies permettant de séparer les contributions des différents trajets, en fonction de leurs angles d'émission et de leurs angles de réception. En plus des mesures des temps de propagation, la tomographie a besoin d'un modèle physique reliant les temps de propagation à la célérité. Deux modèles ont été analysés pendant ces travaux: la théorie classique des rayons, et les Noyaux de Sensibilité du Temps de Propagation (NSTP) obtenus sous l'approximation de Born. Une adaptation des NSTP au cas des mesures obtenues par Double Formation de Voies (D-FV) a été réalisée. Les méthodes développées ont été validées sur des données synthétiques et sur des données "petites échelles" reproduisant la propagation des guides océaniques dans une cuve d'eau de dimensions réduites. L'étude des données ''petites échelles'' a par ailleurs permis d'étudier certains phénomènes physiques: la convection et les vagues de surface.
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Maj, Tomasz. "Interconnection of a 2D vertical-cavity surface-emitting laser array to a receiver array via a fiber image guide." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0034/MQ64236.pdf.
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Maj, Tomasz. "Interconnection of a 2D vertical-cavity surface-emitting laser array to a receiver array via a fiber image guide." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30260.
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Parallel Optical Data Links (PODLs) have the potential to solve interconnection bottlenecks which are currently being experienced in high-speed communication and information processing systems. Such links often require a large number of channels and two-dimensional arrays of active optoelectronic devices are being developed. In order to interconnect these devices, fiber image guide technology consisting of a bundle of several thousand equally spaced optical fibers is being proposed to alleviate the need for dedicated fibers.<br>This thesis examines the implementation of a two-dimensional parallel optical interconnect consisting of an array of Vertical-Cavity Surface-Emitting Lasers (VCSELs), a 1.35m Fiber Image Guide (FIG) and a Metal-Semiconductor-Metal (MSM) receiver array. Coupling issues associated with image guides are analysed and discussed as well as general image guide properties and transmission characteristics. The design, construction and integration aspects of the data link, including optics, electronics and optomechanics are summarised. Characterization results are presented and a transmission rate of 250 Mbit/s per channel is demonstrated with an optical crosstalk of less than -27 dB and a total optical loss of -3dB.
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Jiang, Long yu. "Séparation et détection des trajets dans un guide d'onde en eau peu profonde." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00765238.
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En acoustique sous marine, les 'etudes sur les zones en eau peu profondes sontredevenues strat'egiques. Cette th'ese porte sur l' 'etude de la s'eparation et la d'etectionde trajet dans le cadre des eaux peu profondes tomographie acoustique oc'eanique. Dansune premi'ere 'etape de notre travail, nous avons donn'e un bref aperc¸u sur les techniquesexistantes de traitement acoustique sous-marine afin de trouver la difficult'e toujoursconfront'es 'a ce type de m'ethodes. Par cons'equent, nous avons fait une conclusion qu'ilest encore n'e cessaire d'am'eliorer la r'esolution de s'eparation afin de fournir des informationsplus utiles pour l' 'etape inverse de la tomographie acoustique oc'eanique.Ainsi, une enquˆete sur les mthodes haute r'esolution est effecut'ee. Enfin, nous avonspropos'e une m'ethode 'a haute r'esolution appel'ee lissage MUSICAL (MUSIC Active largeband), qui combine le lissage de fr'equence spatiale avec l'algorithme MUSICAL, pourune s'eparation efficace de trajet coh'erentes ou totalement corr'el'es. Cependant, cettem'ethode est bas'ee sur la connaissance a priori du nombre de trajet. Ainsi, nous introduisonsun test (exponential fitting test) (EFT) 'a l'aide de courte longueur des 'echantillonspour d'eterminer le nombre de trajets. Ces deux m'ethodes sont appliqu'ees 'a la fois desdonn'ees synth'etiques et les donn'ees r'eelles acquises dans un r'eservoir 'a petite 'echelle.Leurs performances sont compar'ees avec les m'ethodes conventionnelles pertinentes.
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Nording, Adam. "Choosing the colors for a company : A case study on how the right colors can mediate the right image of a company." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-173267.
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Our world is made up by millions of colors. Everywhere we go we see a variation of colors that describes the environment. Artists use colors to give an emotion to the viewer and give a deeper meaning to the art. Companies have different colors in their logos and on their websites. For example, a red colored logo can give a feeling of passion, energy and power. But used in a different situation, a red color can implicate dangerand death. The research about colors goes very deep, but there is still alot that has not been tested or discovered. This study will examine whether companies can use colors to mediate the right feeling to their customers. The method to do this included a lot of theoretical background and knowledge about colors. When data was collected a mid-fi prototype of a website was created. This mid-fi website was then transformed into three different high-fi prototypes. The three prototypes had the same content but what put them apart was their color schemes. The tests was done face to face or over the internet. The test person had to answer a short questionnaire were the person described the feelings that appeared when using the three different prototypes. After the test a short interview with each test person took place were some expressions from the test was discussed. The result for the first and second website showed a correlation between the two websites. The users had similar answers on these websites, but they also had some comments that separated the websites. The second website was in the end the most popular website which supported the hypothesis.The conclusion from the study is that colors are a very powerful tool to use if a company wants to attract more customers. This was a quite small study and to draw the conclusion that the right colors actually gives more clicks on a website, a larger and longer study must be made. This is so that the study can compare previous years sales with the year werethey introduced the new color scheme.
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Cedola, Alessia. "Production de faisceaux de rayons-X submicroniques par guide d'onde en couches minces." Université Joseph Fourier (Grenoble ; 1971-2015), 1999. http://www.theses.fr/1999GRE10040.
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Dans cette these on decrit une nouvelle technique utilisant un guide d'onde pour rayons x pour produire un faisceau de dimension submicronique et on presente les proprietes du faisceau autant que un certain nombre d'applications possibles. Le premier chapitre est dedie a une presentation des techniques traditionnelles de production de faisceaux submicroniques. Dans le chapitre ii on presente de facon generale le sujet des ondes stationnaires et la resonance qui se forment dans une couche de materiel leger depose entre deux couches de materiel plus lourd. La resonance produit un faisceau submicronique dont on a mesure les caracteristiques : dimensions geometriques, divergence et coherence. Les performances de la guide d'onde sont aussi discutees avec un regard particulier pour le flux, l'efficience et le gain du systeme et pour les elements qui deteriorent les performances memes. On conclut le chapitre avec une comparaison entre les performances de la guide d'onde et d'autres systemes optiques. Dans le troisieme chapitre on traite la technique du contraste de phase pour l'imagerie a haute resolution. Apres une introduction generale sur cette technique, on presente des mesures de formation d'images par contraste de phase obtenues avec le faisceau submicronique sortant d'une guide d'onde pour rayons x. En ce cas un role tres important est joue par l'agrandissement de l'image due a la divergence angulaire du faisceau, qui permet de se passer de la resolution du detecteur. La comparaison des resultats des mesures faites sur un test pattern avec des simulations numeriques montre qu'une resolution de 0. 1 micron peut etre obtenue. On montre aussi que les donnees experimentales de l'image defocalise peuvent etre elaborees numeriquement pour reconstruire une image reelle de l'objet comparable a celle obtenue avec le microscope electronique.
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Aulanier, Florian. "Tomographie acoustique océanique en guide d'onde : de l'utilisation des temps à celle des angles." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00934791.
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Dans l'océan, les changements de température induisent des perturbations de la vitesse de propagation des ondes acoustiques. A partir des fluctuations des signaux acoustiques enregistrés, la tomographie acoustique océanique permet d'imager ces perturbations de vitesse du son. Dans un contexte de double antenne de réception et d'émission, cette thèse propose une méthode alternative utilisant la direction de propagation des ondes acoustiques et ses paramètres physiques associés, direction d'arrivée (DA) et direction de départ (DD), plutôt que les temps de propagation (TP) utilisés classiquement. Nous nous plaçons dans un guide d'onde océanique petit fond ( 100 m), sur une échelle spatiale entre 1 et 10 km, et une résolution spatiale d'environ 10 m horizontalement et 2 m en profondeur. Dans ce cas, les ondes acoustiques basses fréquences (1 kHz) se réfléchissent sur les interfaces du guide d'ondes et se propagent entre une source et un récepteur, en suivant des trajectoires multiples. Après extraction des TP, DA et DD par double formation de voies, et dans l'hypothèse de faibles perturbations, nous relions linéairement les variations des TP, DA et DD aux perturbations de la distribution de vitesse du son de manière analytique. Cette formulation, basée sur la physique de la diffraction de Born au 1er ordre, utilise des fonctions appelées : noyaux de sensibilité temps-angles (NSTA). Ainsi après avoir traiter le problème direct, l'utilisation de méthodes d'inversion nous permet alors de retrouver les perturbations de vitesse à partir des variations de TP, DA et DD en utilisant les NSTA. Dans cette thèse, nous montrons que l'inversion utilisant uniquement les angles est identique à celle classiquement réalisée avec les temps. Cette méthode nouvelle de tomographie acoustique, a été validée sur données simulées, et sur des données réelles d'expériences à échelle réduites.
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Karsheimer, Emma, and Madelene Svensson. "Effekten av en stjärna : En undersökning om branschutmärkelsers effekter ur ett kundperspektiv." Thesis, Linnéuniversitetet, Institutionen för marknadsföring (MF), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-76307.
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Syfte och forskningsfrågor Syftet med denna studie är att identifiera eventuella effekter som branschutmärkelser kan ha på kundens medvetenhet, attityd, lojalitet respektive kundens självbild gentemot ett varumärke. Frågorna som studien svarar på är: Vilken effekt har branschutmärkelser på varumärkesmedvetenhet, varumärkes- attityd och varumärkeslojalitet? Vilken effekt har branschutmärkelser på kundens självbild? Metod Denna studie har till stor del en deduktiv ansats med utformade hypoteser. En enkätundersökning genomfördes med frågor som grundades i teorin. Den insamlade datan analyserades genom både ett kvantitativt och kvalitativt perspektiv. I den kvantitativa analysen identifierades ett medelvärde på enkätsvaren som sedan ställdes mot ett tröskelvärde. I den kvalitativa analysen tolkades och förklarades svarens betydelse vidare. Slutsats Enligt denna studie leder inte branschutmärkelser till ökad varumärkesmedvetenhet, positiva varumärkesattityder eller en ökad varumärkeslojalitet. Enskilda komponenter inom undersökningsområdena har visat på ett svagt ökande. Enligt resultatet har dock branschutmärkelser generellt en neutral effekt, det vill säga att samtidigt som inte markanta ökningar har identifierats har inte heller några markanta minskningar noterats. Resultaten som visade på svagast effekt utav branschutmärkelser tillhörde kundens självbild.<br>Purpose and research questions The purpose of this study is to identify possible effects that industry awards might have on consumer awareness, attitude, loyalty and on consumer’s self-image towards a brand. The following research questions are answered through the study: Which effect do industry awards have on brand awareness, brand attitude and brand loyalty? Which effect do industry awards have on the consumer’s self-image? Method This study largely takes on a deductive approach by formulating hypotheses. A survey was conducted with questions based on the theory. The collected data was analyzed through a quantitative as well as a qualitative perspective. The quantitative analysis identified a survey mean which was evaluated against a threshold value. In the qualitative analysis, the significance of the answers was further interpreted and explained. Conclusion According to the results of this study, industry awards do not lead to an increase of brand awareness, positive brand attitudes or an increased brand loyalty. A few of the separate components within the scopes of survey has shown a vague increase. However, according to the result industry awards have a neutral effect. This means that at the same time as no significant increases have been identified, neither have any significant decreases. Furthermore, the results showed that the consumer’s self-image had the lowest effect of industry awards.
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Grandidier, Jonathan. "Guide plasmonique polymère-métal : composants passifs et actifs pour la photonique intégrée." Phd thesis, Université de Bourgogne, 2009. http://tel.archives-ouvertes.fr/tel-00441225.
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Les guides d'onde plasmoniques induits par un ruban diélectrique (DLSPPWs pour "Dielectric Loaded Surface Plasmon Polariton Waveguides") permettent de transmettre à une échelle sub-longueur d'onde, des signaux électriques et plasmoniques (ondes optiques à l'interface entre un métal et un diélectrique) dans la même circuiterie. De plus, l'utilisation d'un ruban de polymère comme diélectrique permet de fonctionnaliser ces DLSPPWs. Cette configuration est par conséquent d'un grand intérêt pour des applications en photonique intégrée. Néanmoins, les DLSPPWs souffrent de pertes importantes en raison de la dissipation dans le métal. Nous abordons le problème en montrant qu'il est possible de compenser les pertes en utilisant une configuration analogue à celle d'un amplificateur optique. Nous mettons d'abord en place les outils théoriques (modèle de l'indice effectif), numériques (méthode différentielle et méthode de la fonction de Green) et expérimentaux (microscopie à fuites radiatives) adaptés à l'optimisation et la caractérisation des DLSPPWs. Une fois le confinement modal maximisé à la longueur d'onde telecom λ=1.55 µm, nous considérons un polymère dopé avec des boîtes quantiques. Le mode plasmon guidé dans le système polymère dopé-métal est excité pendant qu'un laser pompe les boîtes quantiques dans leur état excité. La relaxation des boîtes quantiques par émission stimulée de plasmon-polariton de surface apporte un gain optique. Ce phénomène est caractérisé par microscopie à fuites radiatives dans l'espace direct et dans l'espace réciproque. Cette démonstration représente un élément clé pour la photonique intégrée et l'interconnexion de circuits tout-optiques miniaturisés.
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Moroz, Nataliia. "Patrimoines, patrimonialisation, dépatrimonialisation : quelles images et quelles pratiques touristiques pour l'Ukraine ?" Thesis, Lyon, 2020. http://www.theses.fr/2020LYSE2030.
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L’Ukraine, objet et terrain d’études, revêt un double enjeu, à la fois scientifique et opérationnel. Ce pays qui reste encore peu attractif pour les clientèles européennes pour ses ressources touristiques et patrimoniales, souhaite embrayer afin d’améliorer son positionnement sur le marché touristique en s’inspirant des pratiques et des expertises françaises. Il y a donc dans cette recherche doctorale deux volets qui sont nécessairement articulés : un premier de connaissance et d'analyse des systèmes touristiques et patrimoniaux ukrainiens, un second de propositions – à partir des savoir-faire français - destinées à participer aux recherches ukrainiennes en la matière. Le contexte géopolitique actuel du territoire ukrainien depuis novembre 2013 et son aggravation durant la période 2014–2015 a influé sur le déroulement et les terrains pressentis mais plus encore sur le cadre des problématiques initialement posé. Celui-ci, centré sur les stratégies du secteur touristique ukrainien à partir de l’exemple de 4 territoires dont la Crimée, a été réorienté de fait vers l’étude du patrimoine culturel comme ressource touristique ukrainienne visant le développement d’un nouveau segment touristique. Pour identifier des points d’attractivité touristique en Ukraine pour les touristes étrangers et les marqueurs territoriaux nécessaires à l’établissement d’un tourisme de niche, deux approches sont mobilisées. Se donner les moyens de définir objectivement "l’image" du pays et de ses territoires pour en caractériser les éléments patrimoniaux susceptibles de concourir à une meilleure visibilité ukrainienne. Ces approches ont nécessité la délimitation pertinente et l’analyse de plusieurs corpus : guides et brochures touristiques, listes du patrimoine culturel classé, questionnaires auprès de touristes. Les changements et tensions géopolitiques en Ukraine ont singulièrement perturbé l'accès aux données : certaines d'entre elles ont totalement disparu. Il s’agit en premier lieu des statistiques touristiques de certains territoires en tension (régions de Donetsk, Luhansk, de la Crimée). De surcroît, les listes du patrimoine culturel classé ont subi des transformations suite aux lois dites de « désoviétisation », entrainant la suppression des listes patrimoniales de la période soviétique. Cette « dé-patrimonialisation » a également concerné certains monuments et objets patrimoniaux considérés comme « portant l’idéologie du régime communiste ». Finalement, cette difficulté d'accès à des sources comparables dans la durée à l'échelle nationale comme le mouvement de dépatrimonialisation officielle ont conduit à un repositionnement partiel de la problématique, anciens et nouveaux patrimoines mobilisant autrement la question de la mémoire et de l'identité ukrainiennes. L’approche diachronique utilisée dans l’explication des évolutions touristiques et patrimoniales institutionnelles a été mise en perspective sur un temps plus long. C'est ainsi que l'exploration et l'analyse des guides touristiques depuis le début du XXème siècle a permis de resituer plus largement les représentations et discours touchant au fait touristique et donc à l'identité ukrainienne par l'intermédiaire de ses patrimoines. Un travail de représentations des données – graphiques, tableaux synoptiques, cartographies – a été effectué pour mieux visualiser les éléments comparatifs, dans leurs diachronies comme dans leurs spatialisations. Il a nourri un diagnostic mettant en évidence les disparités relatives aux flux touristiques, aux marqueurs territoriaux comme aux objets patrimoniaux classés. Ces analyses induisent quelques préconisations pour la mise en place d’un tourisme de niche, centré sur l'articulation des offres touristico-patrimoniales, en fonction de données statistiques accessibles mais en conservant un souci de vigilance quant à leur fiabilité<br>Ukraine, as an object and a field of study, has a double challenge, both scientific and operational. This country, remaining still unattractive to European customers for its tourist and heritage resources, wishes to embark on a process of improving its positioning on the tourist market by drawing inspiration from French practices and expertise. This doctoral research therefore has two necessarily interlinked components: firstly, the study and analysis of Ukrainian tourism and heritage systems, and secondly, the proposals based on French know-how, intended to participate in Ukrainian research in this field.The current geopolitical context of the Ukrainian territory since November 2013 and its worsening during the 2014–2015 period has influenced the development and the established areas, but even more in the context of the problems initially posed. That development, initially focused on the strategies of the Ukrainian tourism sector starting from the example of 4 territories including Crimea, in fact was reoriented towards the study of cultural heritage as an Ukrainian tourist resource in order to develop a new tourist segment.Two approaches are used in order to identify points of tourism attraction in Ukraine for foreign tourists and the territorial markers necessary for establishing niche tourism. The first one is to find the means to objectively define the "image" of the country and its territories; the second one is to characterize the heritage elements likely to contribute to better Ukrainian visibility. These approaches have required the relevant delimitation and analysis of several corpuses: travel guides, lists of classified cultural heritage, questionnaires among tourists.Geopolitical changes and tensions in Ukraine have significantly disrupted access to data: some of them have completely disappeared. First of all, there are the tourist statistics of certain regions in tension (Donetsk, Luhansk, Crimea regions). In addition, the lists of classified cultural heritage have undergone transformations following the so-called "de-Sovietization" laws, leading to the abolition of heritage lists from the Soviet period. This "de-patrimonialization" also concerns certain monuments and heritage objects considered as "bearing the ideology of the communist regime". Finally, this difficulty of access to sources that are comparable over time on a national scale, such as official depatrimonialisation movement, has led to a partial repositioning of the research issues, with old and new heritages mobilizing the question of memory and Ukrainian identity in a different way.The diachronic approach used in explaining the tourism and institutional heritage evolutions has been put into perspective over a longer period of time. This is how the exploration and analysis of travel guides since the beginning of the XXth century has made it possible to resituate more widely the representations and discourses relating to tourism and therefore to Ukrainian identity through its heritage.Data representation work - graphs, synoptic tables, maps – has been carried out to better visualize the comparative elements, in their diachrony as well as in their spatializations. It has contributed to a diagnosis highlighting the disparities relating to tourist flows, territorial markers as well as classified heritage objects. These analyses lead to some recommendations for the implementation of niche tourism, centered on the articulation of tourist-heritage offers, based on accessible statistical data, but with a concern for vigilance as to their reliability
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Nassif, Marcel. "Méthode de fabrication additive endoscopique par photopolymérisation pour la réparation in-situ de systèmes en espace contraint." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2684.
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Cette thèse est dédiée à l’étude et au développement d’une méthode endoscopique d'impression additive par photo-polymérisation. Le principe de l'endoscopie permet d'imprimer des objets en 3D ou de réparer des pièces endommagées dans un assemblage mécanique dense sans le démonter. La thèse consiste, après étude de l’état de l’art, à proposer des solutions adaptées à la problématique endoscopique, puis modéliser, concevoir, réaliser et valider expérimentalement deux principaux sous-systèmes (photo-polymérisation UV par guide d’image, pulvérisation de résine par conduit tubulaire) qui, une fois synchronisés, permettent l’impression additive par voie endoscopique. Le principe d’impression additive proposé et étudié est inspiré de la méthode de photo-polymérisation en cuve. Une résine liquide est transmise par voie endoscopique et pulvérisée sur la surface d'impression. Suite à cette pulvérisation, un motif UV, structuré par une matrice de micro-miroir de type DMD (Digital Micromirror Device), est transmis par guide d'image et focalisé sur la surface d'impression pour polymériser certaines zones d’une couche de résine liquide. Ces deux étapes sont effectuées plusieurs fois de façon à imprimer des couches superposées pour l’obtention finale d’une pièce en trois dimensions. Un système d'actionnement de la sonde endoscopique (platine de translation non intégrée) permet de maintenir la sonde à une distance de la surface d'impression égale à la distance focale de l’objectif de l’instrument. Dans cette thèse, le système de projection UV endoscopique a été conçu, modélisé, réalisé et testé. La conception et les performances du système optique ont été publiés dans des actes de conférence. Des objets multicouches ont été fabriqués avec une épaisseur de couche de 50 μm, sur une surface d'impression circulaire de 9,54 mm de diamètre. Une méthode d'analyse optique basée sur l'utilisation des fonctions de transfert de modulation (MTF) est utilisée pour tester les performances de l'instrument optique endoscopique et pour caractériser la résolution des pièces imprimées. En exploitant la méthode MTF de façon expérimentale, une chute de la résolution optique due au guide d'image a été estimée à 16 μm par rapport à la valeur obtenue dans le montage expérimental contenant les mêmes composants optiques, à l'exception du guide d'image. La résolution latérale des pièces imprimées est finalement de 50 μm, la limite n’étant pas liée à la résolution latérale du système optique mais à la nature de la résine utilisée. Dans cette thèse, un système de pulvérisation par voie tubulaire a également été dimensionné, réalisé et testé. Un système d'atomisation endoscopique a été mis en place pour permettre un dépôt à distance de la résine sur la surface d'impression. Le choix d’une méthode d'atomisation par air a été adopté. La conception, le contrôle et la réalisation du système d'atomisation sont présentés. Le système de pulvérisation et le système de projection de motifs UV ont été finalement combinés. Des résultats préliminaires d'impression d'objets ont été obtenus et des pièces 3D d'une épaisseur de 0,65 mm ont été imprimées (9 couches). À cause d’un phénomène nommé « overspray » (durant le processus de pulvérisation, la résine atteint la surface d'impression et est poussée sur les côtés par la pression de l’air qui la pulvérise), l'épaisseur des couches n'est pas constante, mais diminue progressivement, le réglage des paramètres de pulvérisation devient alors critique. Différentes perspectives de ce travail de thèse ont été identifiées. Le système de pulvérisation doit encore être optimisé afin de résoudre le problème posé par le phénomène d’overspray. De plus, une pré-étude d’un système de visualisation intégré a été effectuée, qui demande à être approfondie, pour permettre un contrôle de la photo-polymérisation en cours d’impression<br>This thesis concerns the study and the development of a novel endoscopic 3D printing process based on photo-polymerization. The idea behind endoscopic 3D printing is to print 3D objects or to repair damaged parts in a dense mechanical assembly without disassembling it. The thesis aims, once the state of the art is studied, to propose solutions adapted to the endoscopic problem, then to model, design, realize and experimentally validate the two main subsystems (UV photo-polymerization through an image guide, resin spraying through a tubular pipe) which, once synchronized, provide the additive printing. Inspired by the vat polymerization method, the liquid resin is transmitted endoscopically and sprayed onto the printing surface (spraying system). Then, a UV pattern, structured by a DMD (Digital Micromirror Device), is transmitted through the image guide and focused onto the printing surface to polymerize a layer of liquid resin. These two steps are repeated several times in order to print layers on top of each other to obtain a 3D part. An endoscopic actuation system (non-integrated translation actuator) allows maintaining the probe at a distance from the printing surface equal to the focal length of the objective of the instrument. In this thesis, the endoscopic UV projection system was designed, modeled, implemented and tested. The design and performances of the optical system were presented in two international conferences. Multilayer objects were fabricated with a layer thickness of 50 μm on a circular printing area of 9.54 mm in diameter. An optical analysis method based on the use of the modulation transfer functions (MTF) was used to test the performance of the endoscopic optical system and to characterize the lateral resolution of the printed parts. Using the MTF method experimentally, a drop in optical resolution due to the image guide was estimated as high as 16 μm compared to the value obtained in the experimental setup containing the same optical components except for the image guide. The lateral resolution of the printed parts was finally limited by the resin (50 μm) and not by the resolution of the optical system. An endoscopic atomization system was also studied, implemented and tested. An endoscopic spraying system was implemented to allow a remote deposition of the resin onto the printing surface. The choice of an air atomization method was adopted. The design, control and realization of the atomization system are presented. Finally, the spraying system was combined with the UV pattern projection system. Preliminary results of printing objects were obtained and 3D parts with a thickness of 0.65 mm are printed (nine layers). Due to a phenomenon called "overspray" (during the spraying process, the resin reaches the printing area and is pushed to the sides by the air pressure that sprays it), the thickness of the layers is not constant between them, but gradually decreases, so the adjustment of the spraying parameters becomes critical. The spraying system still needs to be optimized in order to eliminate overspray and to be able to print uniform layers with a specific thickness. In addition, we have been working on a 2D visualization system but the lack of light on the printing surface prevents us from being able to visualize and control the system. In the future, we propose to spray a resin mixed with a fluorescent dye to make it possible to distinguish the polymerized zones from the uncured zones in each layer of the part
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BUENO, REGIS C. "Detecção de contornos em imagens de padrões de escoamento bifásico com alta fração de vazio em experimentos de circulação natural com o uso de processamento inteligente." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26817.
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Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T13:03:47Z
No. of bitstreams: 0<br>Made available in DSpace on 2016-11-11T13:03:47Z (GMT). No. of bitstreams: 0<br>Este trabalho desenvolveu um novo método para a detecção de contornos em imagens digitais que apresentam objetos de interesse muito próximos e que contêm complexidades associadas ao fundo da imagem como variação abrupta de intensidade e oscilação de iluminação. O método desenvolvido utiliza lógicafuzzy e desvio padrão da declividade (Desvio padrão da declividade fuzzy - FuzDec) para o processamento de imagens e detecção de contorno. A detecção de contornos é uma tarefa importante para estimar características de escoamento bifásico através da segmentação da imagem das bolhas para obtenção de parâmetros como a fração de vazio e diâmetro de bolhas. FuzDec foi aplicado em imagens de instabilidades de circulação natural adquiridas experimentalmente. A aquisição das imagens foi feita utilizando o Circuito de Circulação Natural (CCN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN). Este circuito é completamente constituído de tubos de vidro, o que permite a visualização e imageamento do escoamento monofásico e bifásico nos ciclos de circulação natural sob baixa pressão.Os resultados mostraram que o detector proposto conseguiu melhorar a identificação do contorno eficientemente em comparação aos detectores de contorno clássicos, sem a necessidade de fazer uso de algoritmos de suavização e sem intervenção humana.<br>t<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Hristova, Hristina. "Example-guided image editing." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S119/document.
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Les contributions de cette thèse sont divisées en trois parties principales. Dans la partie 1, nous proposons une méthode locale utilisant une distribution GGM pour approcher les distributions des images en les subdivisant en groupe de pixels que nous appelons dorénavant clusters. L'idée principale consiste à déterminer quelle caractéristique (couleur, luminance) est plus représentative pour une image donnée. Puis nous utilisons cette caractéristique pour subdiviser l'image en clusters. Quatre stratégies de mise en correspondance des clusters de l'image d'entrée avec ceux de l'image cible sont proposées. Ces stratégies ont pour but de produire des images photoréalistes dont le style ressemble à celui de l'image cible (dans notre cas le style d'une image est défini en termes de couleur et luminosité). Nous étendons le principe de transfert de couleur au transfert simultané de couleur et de gradient. Afin de pouvoir décrire las distributions de couleur et de gradient par une seule distribution, nous adoptons le modèle MGGD (multivariate generalized Gaussian distributions). Nous proposons une nouvelle transformation de distribution MGGD pour des applications de traitement d'image telles que le transfert multi-dimensionnel de caractéristiques d'image, de couleur, etc. De plus, nous adoptons aussi un modèle de distribution plus précis (distribution Beta bornée) pour représenter des distributions de couleur et de luminosité. Nous proposons une transformation de distribution Beta qui permet d'effectuer un transfert de couleur entre images et qui s'avère plus performante que celles basées sur les distributions Gaussiennes. Dans la partie 2, nous introduisons une nouvelle méthode permettant de créer des images HDR à partir d'une paire d'images, l'une prise avec flash et l'autre pas. Notre méthode consiste en l'utilisation d'une fonction de luminosité (brightness) simulant la fonction de réponse d'une caméra, et d'une nouvelle fonction d'adaptation de couleur (CAT), appelée CAT bi-locale (bi-local CAT), permettant de reproduire les détails de l'image flash. Cette approche évite toutes les limitations inhérentes aux méthodes classiques de création d'images HDR. Dans la partie 3, nous exploitons le potentiel de notre adaptation bi-locale CAT pour diverses applications d'édition d'image telles que la suppression de bruit (dé-bruitage), suppression de flou, transfert de texture, etc. Nous introduisons notre nouveau filtre guidé dans lequel nous incorporons l'adaptation bi-locale CAT dans la partie 3<br>This thesis addresses three main topics from the domain of image processing, i.e. color transfer, high-dynamic-range (HDR) imaging and guidance-based image filtering. The first part of this thesis is dedicated to color transfer between input and target images. We adopt cluster-based techniques and apply Gaussian mixture models to carry out a more precise color transfer. In addition, we propose four new mapping policies to robustly portray the target style in terms of two key features: color, and light. Furthermore, we exploit the properties of the multivariate generalized Gaussian distributions (MGGD). in order to transfer an ensemble of features between images simultaneously. The multi-feature transfer is carried out using our novel transformation of the MGGD. Despite the efficiency of the proposed MGGD transformation for multi-feature transfer, our experiments have shown that the bounded Beta distribution provides a much more precise model for the color and light distributions of images. To exploit this property of the Beta distribution, we propose a new color transfer method, where we model the color and light distributions by the Beta distribution and introduce a novel transformation of the Beta distribution. The second part of this thesis focuses on HDR imaging. We introduce a method for automatic creation of HDR images from only two images - flash and non-flash images. We mimic the camera response function by a brightness function and we recover details from the flash image using our new chromatic adaptation transform (CAT), called bi-local CAT. That way, we efficiently recover the dynamic range of the real-world scenes without compromising the quality of the HDR image (as our method is robust to misalignment). In the context of the HDR image creation, the bi-local CAT recovers details from the flash image, removes flash shadows and reflections. In the last part of this thesis, we exploit the potential of the bi-local CAT for various image editing applications such as image de-noising, image de-blurring, texture transfer, etc. We propose a novel guidance-based filter in which we embed the bi-local CAT. The proposed filter performs as good as (and for certain applications even better than) state-of-the art methods
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Moore, George G. "Guided aerial image analysis." Thesis, University of Ulster, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326332.
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Bismuth, Vincent. "Algorithmes de traitement d'images pour la visualisation d'outils interventionnels dans des séquence de fluoroscopie par rayons X." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00747682.
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La pose de stent est l'option de traitement la plus courante de la maladie coronarienne, l'une des principales causes de mortalit e dans le monde. Lors d'une proc edure de pose de stent, le m edecin ins ere des outils chirurgicaux dans le r eseau vasculaire du patient. La progression de ces outils a l'int erieur du corps est suivie en temps r eel sous fluoroscopie par rayons X. Trois outils, en particulier, jouent un role crucial dans la proc edure : le guide, le ballon d'angioplastie et le stent. Le guide apparait dans les images sous la forme d'une structure curviligne. Le ballon, mont e sur le guide, est equip e de deux marqueurs radio-opaques a ses extr emit es. Le stent est un maillage m etallique qui se projette en une forme complexe dans les images fluoroscopique. Le stent, dont le bon d eploiement est essentiel au succ es du geste m edical, est souvent tr es diffi cilement visible dans les images. Les travaux pr esent es dans cette th ese poursuivent un double objectif. Il s'agit d'une part, de concevoir, d' etudier et de valider des techniques de traitement d'image visant a am eliorer la visualisation des stents. D'autre part, nous etudions le traitement des structures curvilignes (comme les guides) pour lesquelles nous proposons un nouvel outil. Nous pr esentons des algorithmes de traitement d'image d edi es a la visualisation 2D et 3D des stents. Nous sommes amen es, dans ce but, a d etecter, suivre et recaler, de mani ere compl etement automatique, les outils n ecessaires a la pose de stent que sont le guide et le ballon. Le stent etant a peine visible dans les images, nous ne cherchons pas a le localiser directement a l'aide de techniques de traitement d'images. La position et le mouvement du stent sont d etermin ees par nos algorithmes a partir de celles de deux amers: le guide et le ballon qui ont des formes caract eristiques. Nous eff ectuons donc, dans ce but, la d etection, le suivi et le recalage de ces amers, et ce de mani ere compl etement automatique. Le coe ur de notre m ethode de visualisation des stents en 2D r eside dans l'utilisation des amers pour effectuer un d ebruitage compens e en mouvement. Nous avons evalu e la performance des ces outils pour la visualisation des stents en 2D, sur une large base de pr es de 200 cas cliniques. Il en ressort que notre m ethode surpasse les m ethodes utilis ees jusqu'ici sur le plan de la qualit e image. La validation exhaustive que nous avons men e, a confi rm e que nous avions atteint un niveau compatible avec son introduction commerciale. Le logiciel qui en r esulte est d esormais install e sur un grand nombre de sites cliniques, o u il est r eguli erement utilis e. La m ethode de visualisation 3D des stents que nous proposons utilise les amers pour e ffectuer une reconstruction tomographique compens ee en mouvement. Nous exposons des r esultats pr eliminaires sur une base de 22 cas cliniques. Il semble que notre m ethode surpasse les m ethodes pr ec edemment employ ees aussi bien du point de vue de la qualit e image que de l'automatisation. Les m ethodes de visualisation des stents que nous proposons s'appuient sur la segmentation de la portion du guide qui traverse le stent. Nous proposons un nouvel outil pour le traitement de telles structures curvilignes que nous appelons : l'Image de Chemins Polygonaux (acronyme PPI en anglais). Cet outil repose sur la notion de chemin localement optimal. L'un des principaux avantages du PPI est d'uni er dans un meme cadre diff erents concepts pr e-existants. De plus, il permet de controler la r egularit e et la longueur des structures a traiter avec une param etrisation simple et intuitive. A n de tirer pleinement parti des performances du PPI nous proposons un sch ema algorithmique effi cace pour le calculer. Nous illustrons ses utilisations pour la segmentation automatique de guide ou il surpasse les techniques existantes.
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Hamdan, Iyas. "Multimodal Image Registration in Image-Guided Prostate Brachytherapy." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0002/document.
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Le cancer de la prostate est le cancer le plus fréquent chez l'homme en France et aux pays occidentaux. Il est la troisième cause de décès liés au cancer, étant responsable d'environ 10% des morts. La curiethérapie, une technique de radiothérapie, est liée à une meilleure qualité de vie après le traitement, par rapport aux autres méthodes de traitement. La curiethérapie de la prostate consiste à insérer des sources radioactives dans la prostate afin de délivrer une dose d'irradiation localisée à la tumeur tout en protégeant les tissus sains environnants. L'imagerie multimodale est utilisée afin d'améliorer la précision du traitement. Les images Tomodensitométriques préopératoires, appelées Computed Tomography (CT), peuvent être utilisées pour calculer une distribution personnalisée et plus précise de dose. Pendant l'intervention, le chirurgien utilise un système de guidage temps-réel par l'Ultrason Transrectale, Transrectal Ultrasound (TRUS), pour placer correctement les sources radioactives dans leurs positions souhaitées. Par conséquent, si les positions des sources sont déterminées sur l'image CT, elles doivent être transférées à l'image US. Cependant, un recalage US/CT direct et robuste est difficilement envisageable parce que les tissus mous, telle que la prostate, offrent peu de contraste en CT et en US. En revanche, l'Imagerie par Résonance Magnétique (IRM) fournit un meilleur contraste et peut, potentiellement, améliorer le traitement en améliorant la visualisation. Donc, ces trois modalités (IRM, CT et US) doivent être correctement alignées. Pour compenser les déformations de la prostate, due au changement de taille et forme entre les différentes acquisitions, un recalage non-rigide est nécessaire. Une méthode de recalage entièrement automatique est nécessaire, afin de faciliter son intégration au bloc opératoire. Nous proposons dans un premier temps un recalage IRM/CT basé sur la maximisation de l'information mutuelle en combinaison avec un champ de déformation paramétré par B-Splines. Nous proposons de contraindre le recalage sur des volumes d'intérêt (VOIs) afin d'améliorer la robustesse et le temps de calcul. L'approche proposée a été validée sur des jeux de données cliniques. Une évaluation quantitative a montré que l'erreur de recalage est égale à 1.15±0.20 mm; qui répond à la précision clinique souhaitée. Ensuite, nous proposons un deuxième recalage US/IRM, où nous utilisons une approche multi-résolution pour éviter les minima locaux et améliorer le temps de calcul. Un critère de similarité, qui met en corrélation l'intensité de l'image US avec l'intensité ainsi que le gradient de l'image IRM, a été utilisé afin de trouver la transformation qui aligne les deux images. Cette méthode a été validée sur un fantôme de prostate dans un premier temps pour évaluer sa faisabilité. Ensuite, elle a été validée sur des jeux de données cliniques en utilisant des critères qualitatives et quantitatives. La distance Hausdorff a montré que l'erreur de recalage est égale à 1.44±0.06 mm. L'approche proposée dans ce travail permet d'aller vers un protocole de curiethérapie guidée par l'imagerie multimodale qui puisse améliorer la précision globale de cette procédure. Malgré ces résultats plutôt encourageants, les travaux futurs impliqueront une évaluation plus approfondie sur plus de jeux de données afin d'évaluer la fiabilité et l'efficacité de cette méthode avant de l'intégrer au bloc opératoire<br>Prostate cancer is the most common cancer in men in France and western countries. It is the third leading cause of death from cancer, being responsible for around 10% of deaths. Brachytherapy, a radiotherapy technique, is associated with a better health-related quality of life after the treatment, compared to other treatment techniques. Prostate brachytherapy involves the implantation of radioactive sources inside the prostate to deliver a localized radiation dose to the tumor while sparing the surrounding healthy tissues. Multi-modal imaging is used in order to improve the overall accuracy of the treatment. The pre-operative Computed Tomography (CT) images can be used to calculate a personalized and accurate dose distribution. During the intervention, the surgeon utilizes a real-time guiding system, Trasnrectal Ultrasound (TRUS), to accurately place the radioactive sources in their desired pre-planned positions. Therefore, if the positions of the sources were determined on CT, they need to be transferred to US. However, a robust and direct US/CT registration is hardly possible since they both provide low soft tissue contrast. Magnetic Resonance Imaging (MRI), on the other hand, has a superior contrast and can potentially improve the treatment planning and delivery by providing a better visualization. Thus, these three modalities (MRI, US and CT) need to be accurately registered. To compensate for prostate deformations, caused by changes in size and form between the different acquisitions, non-rigid registration is essential. Fully automatic registration methodology is necessary in order to facilitate its integration in a clinical workflow. At first, we propose a registration between pre-operative MR and CT images based on the maximization of the mutual information in combination with a deformation field parameterized by cubic B-Splines. We propose to constrain the registration to volumes of interest (VOIs) in order to improve the robustness and the computational efficiency. The proposed approach was validated on clinical patient datasets. Quantitative evaluation indicated that the overall registration error was of 1.15±0.20 mm; which satisfies the desired clinical accuracy. Then, we propose a second intra-operative US/MRI registration, where a multi-resolution approach is implemented to reduce the probability of local minima and improve the computational efficiency. A similarity measure, which correlates intensities of the US image with intensities and gradient magnitude of the MRI, is used to determine the transformation that aligns the two images. The proposed methodology was validated on a prostate phantom at first to assess its feasibility. Subsequently, the method was validated on clinical patient datasets and evaluated using qualitative and quantitative criteria, resulting in a registration error of 1.44±0.06 mm. The approach proposed in this work allows going towards a multimodal protocol for image-guided brachytherapy which can improve the overall accuracy of this procedure. Despite such encouraging results, future work will involve further evaluation on a larger number of datasets in order to assess the reliability and the efficiency of this methodology before integrating it in a clinical workflow
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Sdiri, Bilel. "2D/3D Endoscopic image enhancement and analysis for video guided surgery." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCD030.
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Grâce à l’évolution des procédés de diagnostiques médicaux et les développements technologiques, la chirurgie mini-invasive a fait des progrès remarquables au cours des dernières décennies surtout avec l’innovation de nouveaux outils médicaux tels que les systèmes chirurgicaux robotisés et les caméras endoscopiques sans fil. Cependant, ces techniques souffrent de quelques limitations liées essentiellement l’environnement endoscopique telles que la non uniformité de l’éclairage, les réflexions spéculaires des tissus humides, le faible contraste/netteté et le flou dû aux mouvements du chirurgien et du patient (i.e. la respiration). La correction de ces dégradations repose sur des critères de qualité d’image subjective et objective dans le contexte médical. Il est primordial de développer des solutions d’amélioration de la qualité perceptuelle des images acquises par endoscopie 3D. Ces solutions peuvent servir plus particulièrement dans l’étape d’extraction de points d’intérêts pour la reconstruction 3D des organes, qui sert à la planification de certaines opérations chirurgicales. C’est dans cette optique que cette thèse aborde le problème de la qualité des images endoscopiques en proposant de nouvelles méthodes d’analyse et de rehaussement de contraste des images endoscopiques 2D et 3D.Pour la détection et la classification automatique des anomalies tissulaires pour le diagnostic des maladies du tractus gastro-intestinal, nous avons proposé une méthode de rehaussement de contraste local et global des images endoscopiques 2D classiques et pour l’endoscopie capsulaire sans fil.La méthode proposée améliore la visibilité des structures locales fines et des détails de tissus. Ce prétraitement a permis de faciliter le processus de détection des points caractéristiques et d’améliorer le taux de classification automatique des tissus néoplasiques et tumeurs bénignes. Les méthodes développées exploitent également la propriété d’attention visuelle et de perception de relief en stéréovision. Dans ce contexte, nous avons proposé une technique adaptative d’amélioration de la qualité des images stéréo endoscopiques combinant l’information de profondeur et les contours des tissues. Pour rendre la méthode plus efficace et adaptée aux images 3Dl e rehaussement de contraste est ajusté en fonction des caractéristiques locales de l’image et du niveau de profondeur dans la scène tout en contrôlant le traitement inter-vues par un modèle de perception binoculaire.Un test subjectif a été mené pour évaluer la performance de l’algorithme proposé en termes de qualité visuelle des images générées par des observateurs experts et non experts dont les scores ont démontré l’efficacité de notre technique 3D d’amélioration du contraste. Dans cette même optique,nous avons développé une autre technique de rehaussement du contraste des images endoscopiques stéréo basée sur la décomposition en ondelettes.Ce qui offre la possibilité d’effectuer un traitement multi-échelle et d’opérer une traitement sélectif. Le schéma proposé repose sur un traitement stéréo qui exploite à la fois l’informations de profondeur et les redondances intervues,ainsi que certaines propriétés du système visuel humain, notamment la sensibilité au contraste et à la rivalité/combinaison binoculaire. La qualité visuelle des images traitées et les mesures de qualité objective démontrent l’efficacité de notre méthode qui ajuste l’éclairage des images dans les régions sombres et saturées et accentue la visibilité des détails liés aux vaisseaux sanguins et les textures de tissues<br>Minimally invasive surgery has made remarkable progress in the last decades and became a very popular diagnosis and treatment tool, especially with the rapid medical and technological advances leading to innovative new tools such as robotic surgical systems and wireless capsule endoscopy. Due to the intrinsic characteristics of the endoscopic environment including dynamic illumination conditions and moist tissues with high reflectance, endoscopic images suffer often from several degradations such as large dark regions,with low contrast and sharpness, and many artifacts such as specular reflections and blur. These challenges together with the introduction of three dimensional(3D) imaging surgical systems have prompted the question of endoscopic images quality, which needs to be enhanced. The latter process aims either to provide the surgeons/doctors with a better visual feedback or improve the outcomes of some subsequent tasks such as features extraction for 3D organ reconstruction and registration. This thesis addresses the problem of endoscopic image quality enhancement by proposing novel enhancement techniques for both two-dimensional (2D) and stereo (i.e. 3D)endoscopic images.In the context of automatic tissue abnormality detection and classification for gastro-intestinal tract disease diagnosis, we proposed a pre-processing enhancement method for 2D endoscopic images and wireless capsule endoscopy improving both local and global contrast. The proposed method expose inner subtle structures and tissues details, which improves the features detection process and the automatic classification rate of neoplastic,non-neoplastic and inflammatory tissues. Inspired by binocular vision attention features of the human visual system, we proposed in another workan adaptive enhancement technique for stereo endoscopic images combining depth and edginess information. The adaptability of the proposed method consists in adjusting the enhancement to both local image activity and depth level within the scene while controlling the interview difference using abinocular perception model. A subjective experiment was conducted to evaluate the performance of the proposed algorithm in terms of visual qualityby both expert and non-expert observers whose scores demonstrated the efficiency of our 3D contrast enhancement technique. In the same scope, we resort in another recent stereo endoscopic image enhancement work to the wavelet domain to target the enhancement towards specific image components using the multiscale representation and the efficient space-frequency localization property. The proposed joint enhancement methods rely on cross-view processing and depth information, for both the wavelet decomposition and the enhancement steps, to exploit the inter-view redundancies together with perceptual human visual system properties related to contrast sensitivity and binocular combination and rivalry. The visual qualityof the processed images and objective assessment metrics demonstrate the efficiency of our joint stereo enhancement in adjusting the image illuminationin both dark and saturated regions and emphasizing local image details such as fine veins and micro vessels, compared to other endoscopic enhancement techniques for 2D and 3D images
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Penney, Graeme. "Registration of tomographic images to X-ray projections for use in image guided interventions." Thesis, King's College London (University of London), 2000. https://kclpure.kcl.ac.uk/portal/en/theses/registration-of-tomographic-images-to-xray-projections-for-use-in-image-guided-interventions(79e28525-ae06-4843-bd75-e1fab126e434).html.
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This thesis contributes to knowledge by describing a new method to allow information from a pre-operative 3D modality to be used during an intervention which is guided using 2D fluoroscopy images. An algorithm has been designed to obtain the pose of a CT volume with respect to a single fluoroscopy image. The registration algorithm is based on the production of digitally reconstructed radiographs from the CT volume, which are compared to the fluoroscopy image using a similarity measure. The novelty of the work described in this thesis is in both the design of the registration algorithm and also in investigating the specific requirements placed upon a similarity measure when attempting to register a pre-operative CT volume to an interventional fluoroscopy image. Seven similarity measures were investigated. Experiments were carried out to calculate the accuracy and robustness of the registration algorithm using each similarity measure. Initially fluoroscopy and CT images of a lumbar spine phantom were used. The accuracy of the registration algorithm was calculated by comparing the final registration positions with a ``gold-standard'' registration calculated using fiducial markers. More realistic datasets were simulated using the phantom fluoroscopy image with clinical image features overlaid. Results show that the introduction of soft-tissue structures and interventional instruments into the phantom image can have a large effect on the performance of some similarity measures previously applied to 2D-3D image registration. The similarity measures were also tested on clinical data from aortic stenting procedures, where k-fold cross validation was used to obtain an estimate of the registration accuracy. The results from these experiments showed that two measures were able to register accurately (RMS rotational error of 0.76 degrees and RMS in-plane translational error of 0.85mm) and robustly (10% failure rate) even when soft-tissue structures and interventional instruments were present as differences between the images. These two measures were pattern intensity and gradient difference. Finally the thesis describes a novel combination of the 2D-3D registration algorithm with a deformation algorithm. The registration algorithm was used to obtain information on the relative movement of the vertebrae between the pre-operative CT image and interventional fluoroscopy image. This information was then used to warp the pre-operative modality so that it more accurately represented the intra-operative scene.
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Djordjevic, Milos. "Evaluation of Geometric Accuracy and Image Quality of an On-Board Imager (OBI)." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6967.
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<p>In this project several tests were performed to evaluate the performance of an On-Board Imager® (OBI) mounted on a clinical linear accelerator. The measurements were divided into three parts; geometric accuracy, image registration and couch shift accuracy, and image quality. A cube phantom containing a radiation opaque marker was used to study the agreement with treatment isocenter for both kV-images and cone-beam CT (CBCT) images. The long term stability was investigated by acquiring frontal and lateral kV images twice a week over a 3 month period. Stability in vertical and longitudinal robotic arm motion as well as the stability of the center-of-rotation was evaluated. Further, the agreement of kV image and CBCT center with MV image center was examined.</p><p>A marker seed phantom was used to evaluate and compare the three applications in image registration; 2D/2D, 2D/3D and 3D/3D. Image registration using kV-kV image sets were compared with MV MV and MV-kV image sets. Further, the accuracy in 2D/2D matches with images acquired at non-orthogonal gantry angles was evaluated. The image quality in CBCT images was evaluated using a Catphan® phantom. Hounsfield unit (HU) uniformity and linearity was compared with planning CT. HU accuracy is crucial for dose verification using CBCT data.</p><p>The geometric measurements showed good long term stability and accurate position reproducibility after robotic arm motions. A systematic error of about 1 mm in lateral direction of the kV-image center was detected. A small difference between kV and CBCT center was observed and related to a lateral kV detector offset. The vector disagreement between kV- and MV-image centers was 2 mm at some gantry angles. Image registration with the different match applications worked sufficiently. 2D/3D match was seen to correct more accurately than 2D/2D match for large translational and rotational shifts. CBCT images acquired with full-fan mode showed good HU uniformity but half fan images were less uniform. In the soft tissue region the HU agreement with planning CT was reasonable while a larger disagreement was observed at higher densities. This work shows that the OBI is robust and stable in its performance. With regular QC and calibrations the geometric precision of the OBI can be maintained within 1 mm of treatment isocenter.</p>
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Pace, Aaron J. "Guided Interactive Machine Learning." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1355.pdf.
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Lindskog, Maria. "Clinical Investigations of Image Guided Radiation Therapy for Prostate Cancer with an On-Board Imager." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8320.
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<p>The daily uncertainty concerning tumor localization is one of the major problems during the course of radiation therapy. Image guided-radiation therapy (IGRT) can be used to improve the localization and adjustment of the planning target volume. The aim of this work was to evaluate both the IGRT technique used for prostate cancer patients at the department of the Karolinska University Hospital and an alternative on-line adaptive radiation therapy (ART) method with an On-Board Imager (OBI).</p><p>In the first part of the thesis 2D and 3D image registration with an OBI were compared. Ten prostate cancer patients were involved in the analyses. Two different statistical tests were used to determine significant systematic deviations between the two methods. The second part concerns daily dose verifications and dose plan reoptimization of one intensity modulated radiation therapy (IMRT) prostate cancer patient treated with IGRT. The study was based on cone-beam computed tomography (CBCT) images acquired at 6 different treatment fractions. The risk of developing late rectal and bladder toxicity was quantified using normal tissue complication probability (NTCP) calculations. Additional measurements on an Alderson phantom were performed to verify the accuracy of using the CBCT images for dose calculations.</p><p>A statistically significant difference between the 2D-2D and the 3D-3D match applications could be observed in lateral and longitudinal direction. However, the effect differed among the patients. The phantom measurements showed small dose deviations between the CT and CBCT image, with a mean dose increase to the prostate and seminal vesicles (SV) of 2.5 %. The daily dose to the prostate and SV of the IMRT patient showed to be satisfactory. The daily dose to the rectum did not exceed the prescribed rectal dose except at one treatment fraction and the highest risk of developing late rectal toxicity was about 10.4 %. Large daily bladder dose variations were observed and at two treatment fractions the bladder dose restrictions were exceeded. With a reoptimization process of the dose plan, the dose to the bladder could be reduced while conserving the dose to the target.</p><p>This work shows that for these specific patient cases appropriate doses to the prostate and SV can be delivered with IGRT. However, introducing a suitable ART method could lead to a reduction of inter-fractional rectal and bladder dose variations.</p>
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Barley, Maya. "Bioelectrical strategies for image-guided therapies." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39571.
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Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2007.<br>Includes bibliographical references (leaves 152-157).<br>There is a pressing need in minimally-invasive surgery for novel imaging methods that can rapidly and accurately localize the surgical instrument and its target. We have developed two novel localization methods for the guidance of cardiac ablation and other minimally-invasive therapies. The first method, the Inverse Solution Guidance Algorithm (ISGA), is for the non-invasive and rapid localization of the site of origin of an arrhythmia and an ablation catheter tip from body-surface ECG signals. We have substantially developed ISGA to provide accurate catheter guidance even in the presence of significant electrical inhomogeneities, and we have evaluated the method in numerical simulations and phantom studies. Due to the rapidity of arrhythmic origin localization, ISGA may prove a highly effective means of guiding the ablative therapy of hemodynamically-unstable VT. The second method, the Bioelectrical Image Guidance (BIG) Method, is a novel algorithm for the accurate and inexpensive guidance of a wide-range of minimally-invasive surgeries, from cardiac ablation to breast cancer biopsy.<br>(cont.) The surgical instrument is localized within a detailed 3-D MRI or CT image by applying currents to the body surface and comparing the potentials measured at the instrument tip with potential distributions simulated prior to the surgery. We have developed and evaluated this method in numerical simulations. We have also built an experimental guidance system and tested it in a phantom model. Our results indicate that the BIG Method may one day provide an accurate and convenient means by which to guide minimally-invasive surgery within a highly detailed anatomical image.<br>by Maya E. Barley.<br>Ph.D.
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Chang, Ping-Lin. "Dense vision in image-guided surgery." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24808.
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Image-guided surgery needs an efficient and effective camera tracking system in order to perform augmented reality for overlaying preoperative models or label cancerous tissues on the 2D video images of the surgical scene. Tracking in endoscopic/laparoscopic scenes however is an extremely difficult task primarily due to tissue deformation, instrument invasion into the surgical scene and the presence of specular highlights. State of the art feature-based SLAM systems such as PTAM fail in tracking such scenes since the number of good features to track is very limited. When the scene is smoky and when there are instrument motions, it will cause feature-based tracking to fail immediately. The work of this thesis provides a systematic approach to this problem using dense vision. We initially attempted to register a 3D preoperative model with multiple 2D endoscopic/laparoscopic images using a dense method but this approach did not perform well. We subsequently proposed stereo reconstruction to directly obtain the 3D structure of the scene. By using the dense reconstructed model together with robust estimation, we demonstrate that dense stereo tracking can be incredibly robust even within extremely challenging endoscopic/laparoscopic scenes. Several validation experiments have been conducted in this thesis. The proposed stereo reconstruction algorithm has turned out to be the state of the art method for several publicly available ground truth datasets. Furthermore, the proposed robust dense stereo tracking algorithm has been proved highly accurate in synthetic environment (< 0.1 mm RMSE) and qualitatively extremely robust when being applied to real scenes in RALP prostatectomy surgery. This is an important step toward achieving accurate image-guided laparoscopic surgery.
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Kochan, Martin. "Enhancing registration for image-guided neurosurgery." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10045247/.
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Pharmacologically refractive temporal lobe epilepsy and malignant glioma brain tumours are examples of pathologies that are clinically managed through neurosurgical intervention. The aims of neurosurgery are, where possible, to perform a resection of the surgical target while minimising morbidity to critical structures in the vicinity of the resected brain area. Image-guidance technology aims to assist this task by displaying a model of brain anatomy to the surgical team, which may include an overlay of surgical planning information derived from preoperative scanning such as the segmented resection target and nearby critical brain structures. Accurate neuronavigation is hindered by brain shift, the complex and non-rigid deformation of the brain that arises during surgery, which invalidates assumed rigid geometric correspondence between the neuronavigation model and the true shifted positions of relevant brain areas. Imaging using an interventional MRI (iMRI) scanner in a next-generation operating room can serve as a reference for intraoperative updates of the neuronavigation. An established clinical image processing workflow for iMRI-based guidance involves the correction of relevant imaging artefacts and the estimation of deformation due to brain shift based on non-rigid registration. The present thesis introduces two refinements aimed at enhancing the accuracy and reliability of iMRI-based guidance. A method is presented for the correction of magnetic susceptibility artefacts, which affect diffusion and functional MRI datasets, based on simulating magnetic field variation in the head from structural iMRI scans. Next, a method is presented for estimating brain shift using discrete non-rigid registration and a novel local similarity measure equipped with an edge-preserving property which is shown to improve the accuracy of the estimated deformation in the vicinity of the resected area for a number of cases of surgery performed for the management of temporal lobe epilepsy and glioma.
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Dandekar, Omkar. "High-performance 3D image processing architectures for image-guided interventions." College Park, Md. : University of Maryland, 2008. http://hdl.handle.net/1903/8096.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2008.<br>Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Langø, Thomas. "Ultrasound Guided Surgery: Image Processing and Navigation." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-491.
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<p>The need for spectrally efficient transmission on mobile and wireless channels is prevalent. A promising scheme for such transmission is adaptive coded modulation. In this thesis, techniques for assessing the performance of such systems are presented. One of the vulnerable points of such systems is the need for a reliable feedback channel. Channel prediction is proposed as a technique to combat the harmful effects of feedback delay.</p><p>The Nakagami distribution is often employed in a model for the fading envelope of a wireless channel; this leads to a gamma-distributed signaltonoise ratio. Nakagami (1960) provides expressions for the probability density function (PDF) of the product, sum, and ratio of two correlated gamma-distributed random variables (RVs). However, such an expression for the difference between two such RVs has not been provided by Nakagami.</p><p>A new expression for this PDF is provided in this dissertation, and it is shown that it is closely related to a distribution first described by McKay (1932). Applications of the new PDF include outage probability calculation in an environment with self-interference and assessment of the quality of certain channel estimation techniques.</p>
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Langari, Bahareh. "Multi-scale edge-guided image gap restoration." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13406.
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The focus of this research work is the estimation of gaps (missing blocks) in digital images. To progress the research two main issues were identified as (1) the appropriate domains for image gap restoration and (2) the methodologies for gap interpolation. Multi-scale transforms provide an appropriate framework for gap restoration. The main advantages are transformations into a set of frequency and scales and the ability to progressively reduce the size of the gap to one sample wide at the transform apex. Two types of multi-scale transform were considered for comparative evaluation; 2-dimensional (2D) discrete cosines (DCT) pyramid and 2D discrete wavelets (DWT). For image gap estimation, a family of conventional weighted interpolators and directional edge-guided interpolators are developed and evaluated. Two types of edges were considered; ‘local’ edges or textures and ‘global’ edges such as the boundaries between objects or within/across patterns in the image. For local edge, or texture, modelling a number of methods were explored which aim to reconstruct a set of gradients across the restored gap as those computed from the known neighbourhood. These differential gradients are estimated along the geometrical vertical, horizontal and cross directions for each pixel of the gap. The edge-guided interpolators aim to operate on distinct regions confined within edge lines. For global edge-guided interpolation, two main methods explored are Sobel and Canny detectors. The latter provides improved edge detection. The combination and integration of different multi-scale domains, local edge interpolators, global edge-guided interpolators and iterative estimation of edges provided a variety of configurations that were comparatively explored and evaluated. For evaluation a set of images commonly used in the literature work were employed together with simulated regular and random image gaps at a variety of loss rate. The performance measures used are the peak signal to noise ratio (PSNR) and structure similarity index (SSIM). The results obtained are better than the state of the art reported in the literature.
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Clonda, Diego. "Automatic thalamic labeling for image-guided neurosurgery." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ44150.pdf.
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Munger, Patrice. "Accuracy considerations in MR image-guided neurosurgery." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22780.
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This thesis studies various aspects of the accuracy issue in image-guided neurosurgery (IGNS). Factors such as registration, MR geometrical distortions and accuracy of digitizing device, are theoretically described in a general model of IGNS.<br>The means of registering the patient to its image data is then studied, starting with the definition of registration error. Computer simulations of registration by homologous point matching are described along with a clinical study comparing homologous point matching and surface matching registration methods.<br>A 3-D MR geometrical distortion experiment performed on a stereotactic frame is presented. These measurements demonstrate the discrepancy that can be observed in the geometry of the frame when imaged with differing read-out gradient directions, and quantitatively evaluate the geometrical distortion associated with the image of the frame of known geometry.<br>Since geometrical distortion of MR images can adversely affect the accuracy of IGNS, the three-point-Dixon MR pulse sequence is evaluated as a means of estimating the magnetic field inhomogeneity, and hence potential geometrical errors in images.<br>Finally, an experimental comparison of mechanical and optical localizing devices is described, resulting in a quantitative estimate of the precision and accuracy of both systems.
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Payne, Janet Susan. "Perceptually guided textural methods for image retrieval." Thesis, Brunel University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422416.
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Cheng, Chi-yuen Harry, and 鄭致遠. "Image-guided adaptive radiotherapy for nasopharyngeal carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47164116.
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Nasopharyngeal carcinoma (NPC) is an endemic malignant disease in
Southern China. Intensity-modulated radiotherapy (IMRT) has been employed as a standard treatment for NPC because it delivers highly conformal dose
distribution to target volumes and spares organs at risk (OARs). The success of radiotherapy depends on the accurate delivery of the planned doses throughout the treatment. This can be achieved with the help of advanced image-guided adaptive radiotherapy (IGART) such as kilovoltage (kV) cone beam computed tomography (CBCT) which can reduce the geometric setup uncertainty, monitor the intra-course anatomic and dosimetric changes and adjust the treatment plan.
The aim of this thesis is to study the role of repeat imaging for NPC and the radiation dose from CBCT to patients. The objectives of this thesis are to evaluate the volumetric and dosimetric changes during a course of IMRT for loco-regionally advanced NPC patients with the contribution of repeat computed tomography (CT) and magnetic resonance imaging (MRI) scans; to quantify the absorbed dose, effective dose and the estimation of the additional risk of inducing fatal cancers from CBCT for NPC patients undergoing IMRT; and to compare the image quality of different head protocols.
Nineteen loco-regionally advanced NPC patients treated with IMRT were recruited prospectively. Repeat CT and MRI were acquired at 30 and 50 Gy
intervals. Recontouring of target volumes and OARs was based on the fused CT-MRI images. Hybrid plans with recontouring were generated. The volumetric and dosimetric changes were assessed by comparing the hybrid plans with the original plan. There was volume reduction of target volumes and parotid glands over the course of IMRT. Relative to the original plan, the hybrid plans demonstrated significantly higher dose to the target volumes with greater dose inhomogeneity, higher maximum doses to the spinal cord and brainstem, and higher medium doses to the parotid glands.
The image quality and dosimetry on the Varian CBCT system between software Versions 1.4.13 (“new” protocol) and 1.4.11 (“old” protocol) were studied. A calibrated Farmer-type ionization chamber and a standard cylindrical Perspex CT dosimetry head phantom were used to measure the weighted CBCT dose index (CBCTDIw) of the Varian CBCT system. The absorbed dose of different organs was measured in a female anthropomorphic phantom with thermoluminescent dosimeters (TLD) and the total effective dose was estimated according to ICRP Publication 103. The dosimetry and image quality were studied for head-and-neck region and comparison was made between the new and old protocols. The values of the CBCTDIw, absorbed dose, effective dose of the new head protocol were much lower than the old head protocol in each imaging group. The additional fatal cancer risk from daily CBCT might be up to 1.6%. In conclusion, replanning with repeat imaging at 30 Gy is essential to keep a satisfactory dose to the target volumes and avoid overdosing the OARs for NPC patients. The new Varian CBCT provides volumetric information for image guidance with acceptable image quality and lower radiation dose. This CBCT gives a better standard for NPC patient daily setup verification.<br>published_or_final_version<br>Clinical Oncology<br>Doctoral<br>Doctor of Philosophy
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Williams, Tamara S. (Tamara Shanese) 1976. "Multi-modal registration for image-guided therapy." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86626.
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Swanepoel, Petrus Johannes. "Omnidirectional image sensing for automated guided vehicle." Thesis, Bloemfontein : Central University of Technology, Free State, 2009. http://hdl.handle.net/11462/39.
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Thesis (M. Tech.) -- Central University of Technology, Free State, 2009<br>Automated Guided Vehicles (AGVs) have many different design specifications, although they all have certain design features in common, for instance they are designed to follow predetermined paths, and they need to be aware of their surroundings and changes to their surroundings. They are designed to house sensors for navigation and obstacle avoidance.
In this study an AGV platform was developed by modifying an electric wheelchair. A serial port interface was developed between a computer and the control unit of the electric wheelchair, which enables the computer to control the movements of the platform.
Different sensors were investigated to determine which would be best suited and most effective to avoid collisions. The sensors chosen were mounted on the AGV and a programme was developed to enable the sensors to assist in avoiding obstacles.
An imaging device as an additional sensor system for the AGV was investigated. The image produced by a camera and dome mirror was processed into a panoramic image representing an entire 360o view of the AGV‟s surroundings. The reason for this part of the research was to enable the user to make corrections to the AGV‟s path if it became stuck along the track it was following.
The entire system was also made completely wireless to improve the flexibility of the AGV‟s applications.
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Volpi, Davide. "New technologies for fluorescence image-guided surgery." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:33c1c1cd-af55-46be-acbe-1181848a799b.
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To date, surgery is the most common and successful way to treat cancer. Tumour identification during surgery, however, can be challenging as it relies on the surgeon’s ability to differentiate healthy from diseased tissue, based on visual appearance and palpation. Additional contrast mechanisms are needed to further improve cancer detection during surgery. In this work, I explore the possibility of improving surgical outcomes by using intra-operative fluorescence imaging technologies to identify otherwise invisible lesions. A theoretical model is developed to quantify and characterise the imaging performance of fluorescence image-guided surgery (FIGS) and to guide the development of imaging systems. This model shows excellent potential for performance characterisation of FIGS devices, particularly when small lesions are involved. The design, development and testing of FIGS devices for open and keyhole surgery are described. These devices exploit near infrared (NIR) wavelengths to achieve a superior depth penetration while minimising tissue autofluorescence. Unlike existing systems, the devices described in this work use a single miniaturised camera to simultaneously detect bright-field and fluorescence from multiple dyes. Practical tests indicate nano-molar detection of clinically approved fluorescence dyes. The proposed technology is tested in a clinical study for detecting the sentinel lymph node (SLN) in gynaecological cancers. Results using two non-specific NIR dyes show excellent SLN detection rate in real time during open surgery and laparoscopy. In addition, multi-spectral fluorescence allows independent visualisation of different lymphatic pathways, crucial for understanding the mechanisms of metastasis through the lymphatic system. The FIGS devices are also used to test novel tumour-specific markers in vivo, ex vivo and in vitro. Promising results are reported, suggesting that this imaging technology is suitable for fluorescence molecular imaging. In conclusion, I report the development and applications of a novel multi-spectral FIGS technology that can effectively improve outcomes in surgical oncology.
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SCHIAPPACASSE, ANDREA. "Intraoperative Navigation Systems for Image-Guided Surgery." Doctoral thesis, Università degli studi di Genova, 2018. http://hdl.handle.net/11567/929148.
Full textAbstract:
Recent technological advancements in medical imaging equipment have resulted in
a dramatic improvement of image accuracy, now capable of providing useful information
previously not available to clinicians. In the surgical context, intraoperative
imaging provides a crucial value for the success of the operation.
Many nontrivial scientific and technical problems need to be addressed in order to
efficiently exploit the different information sources nowadays available in advanced
operating rooms. In particular, it is necessary to provide: (i) accurate tracking of
surgical instruments, (ii) real-time matching of images from different modalities, and
(iii) reliable guidance toward the surgical target. Satisfying all of these requisites
is needed to realize effective intraoperative navigation systems for image-guided
surgery.
Various solutions have been proposed and successfully tested in the field of image
navigation systems in the last ten years; nevertheless several problems still arise in
most of the applications regarding precision, usability and capabilities of the existing
systems. Identifying and solving these issues represents an urgent scientific challenge.
This thesis investigates the current state of the art in the field of intraoperative
navigation systems, focusing in particular on the challenges related to efficient and
effective usage of ultrasound imaging during surgery.
The main contribution of this thesis to the state of the art are related to:
Techniques for automatic motion compensation and therapy monitoring applied
to a novel ultrasound-guided surgical robotic platform in the context of
abdominal tumor thermoablation.
Novel image-fusion based navigation systems for ultrasound-guided neurosurgery
in the context of brain tumor resection, highlighting their applicability
as off-line surgical training instruments.
The proposed systems, which were designed and developed in the framework of
two international research projects, have been tested in real or simulated surgical
scenarios, showing promising results toward their application in clinical practice.
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Rungta, Neha S. "Improving error discovery using guided model checking /." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1555.pdf.
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Kruse, Rachel A. "An analysis of Common Missile and TOW 2B using the Janus combat simulation." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FKruse%5FRachel.pdf.
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