Дисертації з теми "Tracking 2D"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Tracking 2D.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Tracking 2D".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Lebeda, Karel. "2D and 3D tracking and modelling." Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/811206/.
Анотація:
Visual tracking of unknown objects in unconstrained video-sequences is extremely challenging due to a number of unsolved issues. This thesis explores several of these and examines possible approaches to tackle them. The unconstrained nature of real-world input sequences creates huge variation in the appearance of the target object due to changes in pose and lighting. Additionally, the object can be occluded by either parts of itself, other elements of the scene, or the frame boundaries. Observations may also be corrupted due to low resolution, motion blur, large frame-to-frame displacement, or incorrect exposure or focus of the camera. Finally, some objects are inherently difficult to track due to their (low) texture, specular/transparent nature, non-rigid deformations, etc. Conventional trackers depend heavily on the texture of the target. This causes issues with transparent or untextured objects. Edge points can be used in cases where standard feature points are scarce; these however suffer from the aperture problem. To address this, the first contribution of this thesis explores the idea of virtual corners, using pairs of non-adjacent line correspondences, tangent to edges in the image. Furthermore, the chapter investigates the possibility of long-term tracking, introducing a re-detection scheme to handle occlusions while limiting drift of the object model. The outcome of this research is an edge-based tracker, able to track in scenarios including untextured objects, full occlusions and significant length. The tracker, besides reporting excellent results in standard benchmarks, is demonstrated to successfully track the longest sequence published to date. Some of the issues in visual tracking are caused by suboptimal utilisation of the image information. The object of interest can easily occupy as few as ten or even one percent of the video frame area. This causes difficulties in challenging scenarios such as sudden camera shakes or full occlusions. To improve tracking in such cases, the next major contribution of this thesis explores relationships within the context of visual tracking, with a focus on causality. These include causal links between the tracked object and other elements of the scene such as the camera motion or other objects. Properties of such relationships are identified in a framework based on information theory. The resulting technique can be employed as a causality-based motion model to improve the results of virtually any tracker. Significant effort has previously been devoted to rapid learning of object properties on the fly. However, state-of-the-art approaches still often fail in cases such as rapid out-of-plane rotations, when the appearance changes suddenly. One of the major contributions of this thesis is a radical rethinking of the traditional wisdom of modelling 3D motion as appearance change. Instead, 3D motion is modelled as 3D motion. This intuitive but previously unexplored approach provides new possibilities in visual tracking research. Firstly, 3D tracking is more general, as large out-of-plane motion is often fatal for 2D trackers, but helps 3D trackers to build better models. Secondly, the tracker’s internal model of the object can be used in many different applications and it could even become the main motivation, with tracking supporting reconstruction rather than vice versa. This effectively bridges the gap between visual tracking and Structure from Motion. The proposed method is capable of successfully tracking sequences with extreme out-of-plane rotation, which poses a considerable challenge to 2D trackers. This is done by creating realistic 3D models of the targets, which then aid in tracking. In the majority of the thesis, the assumption is made that the target’s 3D shape is rigid. This is, however, a relatively strong limitation. In the final chapter, tracking and dense modelling of non-rigid targets is explored, demonstrating results in even more generic (and therefore challenging) scenarios. This final advancement truly generalises the tracking problem with support for long-term tracking of low texture and non-rigid objects in sequences with camera shake, shot cuts and significant rotation. Taken together, these contributions address some of the major sources of failure in visual tracking. The presented research advances the field of visual tracking, facilitating tracking in scenarios which were previously infeasible. Excellent results are demonstrated in these challenging scenarios. Finally, this thesis demonstrates that 3D reconstruction and visual tracking can be used together to tackle difficult tasks.
2
Trache, Marian Tudor. "The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-202530.
Анотація:
Die technologische Entwicklung im Bereich der Echokardiographie hat in der
letzten Dekade neue Methoden zur objektiven Erfassung der regionalen linksventrikulären
Wandbewegung ermöglicht. Speckle Tracking erfasst die myokardiale Deformation durch
die Positionsänderung einzelner Bildpunkte von einem Bild des analysierten Datensatzes
zum nächsten. Diese Methode ist dem Gewebedoppler überlegen, insbesondere wegen ihrer
Unabhängigkeit vom Anlotungswinkel. Zwei-dimensionale (2D) Speckle Tracking
Analysen wurden für die klinische Praxis validiert. Die drei-dimensionale (3D)
Echokardiographie erlaubt inzwischen Speckle Tracking Analysen von 3D Datensätzen,
welche jedoch für die klinische Praxis noch nicht ausreichend validiert sind.
Bei Patienten mit normaler regionaler linksventrikulärer Wandbewegung (N=37), sowie bei
Patienten mit ischämie-bedingten Wandbewegungsstörungen (N=18) wurden 3D und 2D
Speckle Tracking Analysen durchgeführt. Die Vergleichbarkeit der beiden Methoden
hinschtlich der Quantifizierung von normalen und pathologischen Wandbewegungsmustern
wurde anhand dieser Messungen geprüft. Des weiteren wurde der Einfluss der Bildrate und
Bildqualität drei-dimensionaler Datensätze auf die Vergleichbarkeit beider Methoden
analysiert.
Es zeigte sich eine gute Vergleichbarkeit des 2D und 3D Speckle Tracking in der
Diagnostik eingeschränkter linksventrikulärer systolischer Funktion, sowie in der
Lokalisationsdiagnostik umschriebener Wandbewegungsstörungen. 2D und 3D Speckle
Tracking sind jedoch noch nicht als gleichwertige Methoden anzusehen. Die Bildqualität,
generell bei beiden Modalitäten - jedoch speziell bei 3D Datensätzen, sowie die Bildrate
der 3D Datensätze zeigen signifikante Einflüsse auf die 3D Strain Analysen. Eine korrekte
Standardisierung der analysierten Aufnahmen und eine optimale Bildqualität sind wichtige
Faktoren, die die Zuverlässigkeit des 2D und 3D Speckle Trackings bestimmen.
3
Ren, Yuheng. "Implicit shape representation for 2D/3D tracking and reconstruction." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:c70dc663-ee7c-4100-b492-3a85bf8640d1.
Анотація:
This thesis develops and describes methods for real-time tracking, segmentation and 3-dimensional (3D) model acquisition, in the context of developing games for stroke patients that are rehabilitating at home. Real-time tracking and reconstruction of a stroke patient's feet, hands and the control objects that they are touching can enable not only the graphical visualization of the virtual avatar in the rehabilitation games, but also permits measurement of the patient's performs. Depth or combined colour and depth imagery from a Kinect sensor is used as input data. The 3D signed distance function (SDF) is used as implicit shape representation, and a series of probabilistic graphical models are developed for the problem of model-based 3D tracking, simultaneous 3D tracking and reconstruction and 3D tracking of multiple objects with identical appearance. The work is based on the assumption that the observed imagery is generated jointly by the pose(s) and the shape(s). The depth of each pixel is randomly and independently sampled from the likelihood of the pose(s) and the shape(s). The pose(s) tracking and 3D shape reconstruction problems are then cast as the maximum likelihood (ML) or maximum a posterior (MAP) estimate of the pose(s) or 3D shape. This methodology first leads to a novel probabilistic model for tracking rigid 3D objects with only depth data. For a known 3D shape, optimization aims to find the optimal pose that back projects all object region pixels onto the zero level set of the 3D shape, thus effectively maximising the likelihood of the pose. The method is extended to consider colour information for more robust tracking in the presence of outliers and occlusions. Initialised with a coarse 3D model, the extended method is also able to simultaneously reconstruct and track an unknown 3D object in real time. Finally, the concept of `shape union' is introduced to solve the problem of tracking multiple 3D objects with identical appearance. This is formulated as the minimum value of all SDFs in camera coordinates, which (i) leads to a per-pixel soft membership weight for each object thus providing an elegant solution for the data association in multi-target tracking and (ii) it allows for probabilistic physical constraints that avoid collisions between objects to be naturally enforced. The thesis also explore the possibility of using implicit shape representation for online shape learning. We use the harmonics of 2D discrete cosine transform (DCT) to represent 2D shapes. High frequency harmonics are decoupled from low ones to represent the coarse information and the details of the 2D shape. A regression model is learnt online to model the relationship between the high and low frequency harmonics using Locally Weighted Projection Regression (LWPR). We have demonstrated that the learned regression model is able to detect occlusion and recover them to the complete shape.
4
Yang, Po. "Accuracy improvement of RFID based 2D tracking and localisation." Thesis, Staffordshire University, 2011. http://eprints.staffs.ac.uk/1884/.
Анотація:
The purpose of localization and tracking technology in indoor application is to extract moving object parameters accurately and precisely. This thesis investigates the problem of how to utilize RFID technique for the accurate and precise extraction of indoor 2D moving object position parameters. Firstly, a framework named RFID-Loc with three modules: RFID-Loc Infrastructure, RFID-Loc Data Filter and RFID-Loc Localisation Algorithm, is established from a theoretical perspective. This framework can guide the research and design of methods used in an RFID based object localisation system with enhanced localisation accuracy and precision. Secondly, from practical perspective, few methods are proposed in RFID-Loc framework to improve the localisation accuracy and precision. A sparse RFID Tag Arrangement strategy is proposed in this RFID-Loc framework, aiming at reducing the impacts of regular false reading error from RFID infrastructure level on localisation precision. The efficiency of this methods and the assumptions upon which it relies, are investigated empirically. A rectangle-based feature selection method is justified as the major RFID Data Filter algorithm, with the capability of maximally reducing regular false reading errors. The possibility to resist unexpected false reading error in an RFID-Loc system is investigated by discussing and comparing several RFID-based localisation algorithms. A dynamic localisation algorithm for RFID-Loc system is proposed to accurately and precisely extract moving object position parameters overtime in an RFID-Loc system. This algorithm is shown to have a better capability of resisting unexpected false reading error than conventional localisation algorithms used in RFID-based localisation systems, while having a higher computational complexity. By following the theoretical guidelines in RFID-Loc framework and implementing the proposed methods, the experimental results demonstrate that the localisation accuracy and precision can be significantly improved, up to 10 centimetres and 3 centimetres under current RFID devices.
5
Popov, Pavel Alexandrovich. "Real-time 2D Static Hand Gesture Recognition and 2D Hand Tracking for Human-Computer Interaction." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41556.
Анотація:
The topic of this thesis is Hand Gesture Recognition and Hand Tracking for user interface applications. 3 systems were produced, as well as datasets for recognition and tracking, along with UI applications to prove the concept of the technology. These represent significant contributions to resolving the hand recognition and tracking problems for 2d systems. The systems were designed to work in video only contexts, be computationally light, provide recognition and tracking of the user's hand, and operate without user driven fine tuning and calibration. Existing systems require user calibration, use depth sensors and do not work in video only contexts, or are computationally heavy requiring GPU to run in live situations.
A 2-step static hand gesture recognition system was created which can recognize 3 different gestures in real-time. A detection step detects hand gestures using machine learning models. A validation step rejects false positives. The gesture recognition system was combined with hand tracking. It recognizes and then tracks a user's hand in video in an unconstrained setting. The tracking uses 2 collaborative strategies. A contour tracking strategy guides a minimization based template tracking strategy and makes it real-time, robust, and recoverable, while the template tracking provides stable input for UI applications. Lastly, an improved static gesture recognition system addresses the drawbacks due to stratified colour sampling of the detection boxes in the detection step. It uses the entire presented colour range and clusters it into constituent colour modes which are then used for segmentation, which improves the overall gesture recognition rates.
One dataset was produced for static hand gesture recognition which allowed for the comparison of multiple different machine learning strategies, including deep learning. Another dataset was produced for hand tracking which provides a challenging series of user scenarios to test the gesture recognition and hand tracking system. Both datasets are significantly larger than other available datasets. The hand tracking algorithm was used to create a mouse cursor control application, a paint application for Android mobile devices, and a FPS video game controller. The latter in particular demonstrates how the collaborating hand tracking can fulfill the demanding nature of responsive aiming and movement controls.
6
Stüer, Katharina [Verfasser]. "Echokardiografische Funktionsanalyse des linken Vorhofes mittels 2D-Speckle Tracking / Katharina Stüer." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1075493129/34.
7
Simonnet, Damien Remi Jules Joseph. "Detecting and tracking humans in crowded scenes based on 2D image understanding." Thesis, Kingston University, 2012. http://eprints.kingston.ac.uk/28213/.
Анотація:
Tracking pedestrians in surveillance videos is an important task, not only in itself but also as a component of pedestrian counting, activity and event recognition, and scene understanding in general. Robust tracking in crowded environments remains a major challenge, mainly due to the occlusions and interactions between pedestrians. Methods to detect humans in a single frame are becoming increasingly accurate. Therefore, the majority of multi-target tracking algorithms in crowds follow a tracking-by-detection approach, along with models of individual and group behaviour, and various types of features to re-identify any given pedestrian (and discriminate them from the remainder). The aim is, given a Closed Circuit TeleVision (CCTV) camera view (moving or static) of a crowded scene, to produce tracks that indicate which pedestrians are entering and leaving the scene to be used in further applications (e.g. a multi-camera tracking scenario). Therefore, this output should be accurate in terms of position, have few false alarms and identity changes (i.e. tracks have not to be fragmented nor switch identity). Consequently, the presented algorithm concentrates on two important characteristics. Firstly, production of a real-time or near real-time output to be practically usable for further applications without penalising the final system. Secondly, management of occlusions which is the main challenge in crowds. The methodology presented, based on a tracking-by-detection approach, proposes an advance over those two aspects through a hierarchical framework to solve short and long occlusions with two novel methods. First, at a fine temporal scale, kinematic features and appearance features based on non-occluded parts are combined to generate short and reliable 'tracklets'. More specifically, this part uses an occlusion map which attributes a local measurement (by searching over the non-occluded parts) to a target without a global measurement (i.e. a measurement generated by the global detector), and demonstrates better results in terms of tracklet length without generating more false alarms or identity changes. Over a longer scale, these tracklets are associated with each other to build up longer tracks for each pedestrian in the scene. This tracklet data association is based on a novel approach that uses dynamic time warping to locate and measure the possible similarities of appearances between tracklets, by varying the time step and phase of the frame-based visual feature. The method, which does not require any target initialisations or camera calibrations, shows significant improvements in terms of false alarms and identity changes, the latter being a critical point for evaluating tracking algorithms. The evaluation framework, based on different metrics introduced in the literature, consists of a set of new track-based metrics (in contrast to frame-based) which enables failure parts of a tracker to be identified and algorithms to be compared as a single value. Finally, advantages of the dual method proposed to solve long and short occlusions are to reduce simultaneously the problem of track fragmentation and identity switches, and to make it naturally extensible to a multi-camera scenario. Results are presented as a tag and track system over a network of moving and static cameras. In addition to public datasets for multi-target tracking in crowds (e.g. Oxford Town Centre (OTC) dataset) where the new methodology introduced (i.e. building tracklets based on non-occluded pedestrian parts plus re-identification with dynamic time warping) shows significant improvements. Two new datasets are introduced to test the robustness of the algorithm proposed in more challenging scenarios. Firstly, a CCTV shopping view centre is used to demonstrate the effectiveness of the algorithm in a more crowded scenario. Secondly, a dataset with a network of CCTV Pan Tilt Zoom (PTZ) cameras tracking a single pedestrian, demonstrates the capability of the algorithm to handle a very difficult scenario (abrupt motion and non-overlapping camera views) and therefore its applicability as a component of a multitarget tracker in a network of static and PTZ cameras. The thesis concludes with a critical analysis of the work and presents future research opportunities (notably the use of this framework in a non-overlapping network of static and PTZ cameras).
8
Recatalá, Ballester Gabriel. "Visual determination, tracking and execution of 2D grasps using a behavior-inspired approach." Doctoral thesis, Universitat Jaume I, 2003. http://hdl.handle.net/10803/10371.
Анотація:
This thesis focuses on the definition of a task for the determination, tracking and execution of a grasp on an unknown object. In particular, it is considered the case in which the object is ideally planar and the grasp has to be executed with a two-fingered, parallel-jaw gripper using vision as the source of sensor data. For the specification of this task, an architecture is defined that is based on three basic components -virtual sensors, filters, and actuators-, which can be connected to define a control loop. Each step in this task is analyzed separately, considering several options in some cases.Some of the main contributions of this thesis include: (1) the use of a modular approach to the specification of a control task that provides a basic framework for supporting the concept of behavior; (2) the analysis of several strategies for obtaining a compact representation of the contour of an object; (3) the development of a method for the evaluation and search of a grasp on a planar object for a two-fingered gripper; (4) the specification of different representations of a grasp and the analysis of their use for tracking the grasp between different views of an object; (5) the specification of algorithms for the tracking of a grasp along the views of an object obtained from a sequence of single images and a sequence of stereo images; (6) the definition of parametrized models of the target position of the grasp points and of the feasibility of this target grasp, and of an off-line procedure for the computation of some of the reference values required by this model; and (7) the definition and analysis of a visual servoing control scheme to guide the gripper of a robot arm towards an unknown object using the grasp points computed for that object as control features.
9
Mirpour, Sasha. "A Comparison of 3D Camera Tracking Software." Thesis, University of Gävle, Department of Mathematics, Natural and Computer Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-779.
Анотація:
In the past decade computer generated images have become widely used in the visual effects industry. One of the main reasons is being able to seamlessly blend three dimensional (3D) animation with live-action footage. In this study, different 3D camera tracking software (also referred to as matchmoving) is compared focusing on workflow, user-friendly system, and quality of production.
10
Minetto, Rodrigo 1983. "Reconhecimento de texto e rastreamento de objetos 2D/3D." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275708.
Анотація:
Orientadores: Jorge Stolfi, Neucimar Jerônimo LeiteTese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-20T03:12:07Z (GMT). No. of bitstreams: 1 Minetto_Rodrigo_D.pdf: 35894128 bytes, checksum: 8a0e453fba7e6a9a02fb17a52fdbf878 (MD5) Previous issue date: 2012
Resumo: Nesta tese abordamos três problemas de visão computacional: (1) detecção e reconhecimento de objetos de texto planos em imagens de cenas reais; (2) rastreamento destes objetos de texto em vídeos digitais; e (3) o rastreamento de um objeto tridimensional rígido arbitrário com marcas conhecidas em um vídeo digital. Nós desenvolvemos, para cada um dos problemas, algoritmos inovadores, que são pelo menos tão precisos e robustos quanto outros algoritmos estado-da-arte. Especificamente, para reconhecimento de texto nós desenvolvemos (e validamos extensivamente) um novo descritor de imagem baseado em HOG especializado para escrita romana, que denominamos T-HOG, e mostramos sua contribuição como um filtro em um detector de texto (SNOOPERTEXT). Nós também melhoramos o algoritmo SNOOPERTEXT através do uso da técnica multiescala para tratar caracteres de tamanhos bastante variados e limitar a sensibilidade do algoritmo a vários artefatos. Para rastreamento de texto, nós descrevemos quatro estratégias básicas para combinar a detecção e o rastreamento de texto, e desenvolvemos também um rastreador específico baseado em filtro de partículas que explora o uso do reconhecedor T-HOG. Para o rastreamento de objetos rígidos, nós desenvolvemos um novo algoritmo preciso e robusto (AFFTRACK) que combina rastreamento de características por KLT com uma calibração de câmera melhorada. Nós testamos extensivamente nossos algoritmos com diversas bases de dados descritas na literatura. Nós também desenvolvemos algumas bases de dados (publicamente disponíveis) para a validação de algoritmos de detecção e rastreamento de texto e de rastreamento de objetos rígidos em vídeos
Abstract: In this thesis we address three computer vision problems: (1) the detection and recognition of flat text objects in images of real scenes; (2) the tracking of such text objects in a digital video; and (3) the tracking an arbitrary three-dimensional rigid object with known markings in a digital video. For each problem we developed innovative algorithms, which are at least as accurate and robust as other state-of-the-art algorithms. Specifically, for text classification we developed (and extensively evaluated) a new HOG-based descriptor specialized for Roman script, which we call T-HOG, and showed its value as a post-filter for an existing text detector (SNOOPERTEXT). We also improved the SNOOPERTEXT algorithm by using the multi-scale technique to handle widely different letter sizes while limiting the sensitivity of the algorithm to various artifacts. For text tracking, we describe four basic ways of combining a text detector and a text tracker, and we developed a specific tracker based on a particle-filter which exploits the T-HOG recognizer. For rigid object tracking we developed a new accurate and robust algorithm (AFFTRACK) that combines the KLT feature tracker with an improved camera calibration procedure. We extensively tested our algorithms on several benchmarks well-known in the literature. We also created benchmarks (publicly available) for the evaluation of text detection and tracking and rigid object tracking algorithms
Doutorado
Ciência da Computação
Doutor em Ciência da Computação
11
Willcox, III Eric N. "Forward Perception Using a 2D LiDAR on the Highway for Intelligent Transportation." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-theses/342.
Анотація:
For a little over the past decade since the DARPA Grand Challenge in 2004 and the more successful Urban Challenge in 2007 autonomous vehicles have seen a surge in popularity with car manufacturers, and companies such as Google and Uber. Light Detection And Ranging (LiDAR) has been one of the major sensors in use to sense for acting on the surrounding environment instead of the classic radar which has a much narrower field of vision. However the cost of the higher end 3D LiDAR systems which started seeing use during the DARPA challenges still have the high cost of $70,000 a piece which is an issue when trying to design a consumer friendly system on a family car. This work aims to investigate alternate 2D LiDAR systems to the costly systems currently in use in many prototypes to find a cost efficient alternative that can detect and track obstacles in front of a vehicle. The introduction begins by summarizing some related prior works, particularly papers from after the Grand Challenge as well as some about the competition itself. Detection and tracking methods for point clouds generated by the LiDAR are explored including ways to search through the data in an efficient manner to meet real-time constraints. Some of the trade-offs in going from a 3D system to a 2D system and examined along with how some of the drawbacks can be mitigated.
12
Cinotti, Raphaël. "Evaluation de la fonction systolique ventriculaire gauche par speckle-tracking chez le patient sous ventilation mécanique en anesthésie-réanimation." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT1014/document.
Анотація:
L’analyse de la fonction systolique longitudinale par speckletracking permet d’analyser les mouvements de déformations du myocarde ainsi que la fonction systolique longitudinale ventriculaire gauche. Le Strain Longitudinal Global (SLG) est le paramètre le plus étudié en cardiologie et s’intéresse aux déformations du grand axe du ventricule gauche. Il n’existe pas de données sur le SLG chez les patients atteints d’une pathologie cérébrale aiguë placés sous ventilation mécanique, alors que les cardiopathies de stress ont été largement décrites dans ce contexte. Nous avons évalué le SLG chez des patients atteints d’hémorragie sous-arachnoïdienne par rupture d’anévrysme. Il existait plus de 30% de cardiopathies de stress évaluée par le SLG, alors que la fraction d’éjection ventriculaire gauche était normale. Chez les patients traumatisés crâniens, nous avons observé une absence de cardiopathies de stress, avec un SLG conservé. Néanmoins nous ne pouvons exclure que les anomalies constatées sont liées aux variations des conditions de charge secondaires à la ventilation mécanique. Nous avons testé l’effet de la ventilation mécanique invasive après anesthésie générale au bloc opératoire sur le SLG, ainsi que les effets du lever de jambe passif. Au décours de l’anesthésie générale, il existe une altération modeste mais significative du SLG. Après une épreuve de lever de jambe passif, l’altération du SLG est persistante. En conclusion, les altérations du SLG témoignant d’une cardiopathie de stress, sont spécifiques en neuroréanimation, mais l’analyse du SLG doit prendre en compte les variations rapides de conditions de charge.Speckle-tracking echography allows the analysis of left ventricular strain movements and longitudinal systolic function. Global Longitudinal Strain (GLS) is the most studied parameter in cardiology and provides data regarding strain movements of the left ventricle in the long axis. There are no data regarding SLG in neurocritical care patients undergoing invasive mechanical ventilation, although stress cardiomyopathy has been numerously described in this context. We have studied GLS in patients with aneurysmal subarachnoid haemorrhage. We identified over 30% of stress cardiomyopathy with GLS along with preserved left ventricular ejection fraction. In patients with traumatic brain injury, GLS was preserved implying the absence of stress cardiomyopathy. However, we could not rule out that GLS alterations were the consequences of the variations in the loading conditions of the left ventricle, because of mechanical ventilation. We tested these effects in patients undergoing invasive mechanical ventilation with general anaesthesia in the operating room. We also tested the effects of passive leg raising. After general anaesthesia, we witnessed a moderate but significant GLS impairment. After a passive leg raising test, GLS impairment was still present. In definite, GLS’s modifications are specific of the neurocritical care setting and imply the existence of stress cardiomyopathy, but GLS analysis must consider rapid modifications of the loading conditions
13
Chen, Yangsheng. "Ground Target Tracking with Multi-Lane Constraint." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/925.
Анотація:
Knowledge of the lane that a target is located in is of particular interest in on-road surveillance and target tracking systems. We formulate the problem and propose two approaches for on-road target estimation with lane tracking. The first approach for lane tracking is lane identification based ona Hidden Markov Model (HMM) framework. Two identifiers are developed according to different optimality goals of identification, i.e., the optimality for the whole lane sequence and the optimality of the current lane where the target is given the whole observation sequence. The second approach is on-road target tracking with lane estimation. We propose a 2D road representation which additionally allows to model the lateral motion of the target. For fusion of the radar and image sensor based measurement data we develop three, IMM-based, estimators that use different fusion schemes: centralized, distributed, and sequential. Simulation results show that the proposed two methods have new capabilities and achieve improved estimation accuracy for on-road target tracking.
14
Conte, Armond S. II. "Censoring and Fusion in Non-linear Distributed Tracking Systems with Application to 2D Radar." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4068.
Анотація:
The objective of this research is to study various methods for censoring state estimate updates generated from radar measurements. The generated 2-D radar data are sent to a fusion center using the J-Divergence metric as the means to assess the quality of the data. Three different distributed sensor network architectures are considered which include different levels of feedback. The Extended Kalman Filter (EKF) and the Gaussian Particle Filter (GPF) were used in order to test the censoring methods in scenarios which vary in their degrees of non-linearity. A derivation for the direct calculation of the J-Divergence using a particle filter is provided. Results show that state estimate updates can be censored using the J-Divergence as a metric controlled via feedback, with higher J-Divergence thresholds leading to a larger covariance at the fusion center.
15
da, Silva Daliton. "Uma avaliação de algoritmos de rastreamento 2D para uso em reconstrução 3D." Universidade Federal de Pernambuco, 2010. https://repositorio.ufpe.br/handle/123456789/2256.
Анотація:
Made available in DSpace on 2014-06-12T15:55:49Z (GMT). No. of bitstreams: 2
arquivo2328_1.pdf: 4997289 bytes, checksum: 4012a5235a1aad082afe66cac56457eb (MD5)
license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)
Previous issue date: 2010Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A reconstrução 3D é uma área de pesquisa que consiste em recuperar modelos que representem com precisão e em 3D características de interesse de uma cena, através da extração de informações 3D a partir de imagens 2D. Estas informações podem ser relativas à estrutura de uma determinada cena, posicionamento e trajetória de câmeras, textura, dentre outras. Uma vez de posse de tais informações, podemos utilizá-las para os mais diversos fins, por exemplo, modelagem automática de objetos, sistemas de navegação autônoma de robôs, modelos computacionais de estruturas ou órgãos do corpo humano, posicionamento de elementos virtuais em cenas reais, dentre outros. Uma das formas mais difundidas de se realizar reconstrução 3D é utilizando sequências contíguas de imagens ou vídeos capturados por câmeras convencionais (monoculares). Neste tipo de reconstrução um dos desafios mais importantes é o rastreamento. Rastreamento é a capacidade de conseguir corresponder um conjunto de pontos em uma sequência de imagens, ou seja, dado um ponto A com coordenadas x e y, deve-se ser capaz de identificar o ponto A com coordenadas x e y na imagem seguinte da sequência, e que corresponde exatamente à mesma localidade da estrutura sendo rastreada. Neste contexto, o objetivo desta dissertação de mestrado foi avaliar os algoritmos de rastreamento mais utilizados para este propósito, ressaltando as características individuais de cada um deles e identificando as vantagens e limitações que possuem. Os resultados desta análise podem ser uma ferramenta de auxílio na escolha do algoritmo de rastreamento a ser utilizado quando do desenvolvimento de uma solução de reconstrução 3D, tendo como base o domínio do problema que se deseja atacar. Os três algoritmos analisados foram o SIFT, o KLT e outro Baseado em Similaridade. Foi desenvolvida uma ferramenta de reconstrução 3D baseada em SfM. Esta ferramenta foi utilizada para a coleta de resultados com o rastreamento sendo realizado com SIFT, KLT e Similaridade. Uma etapa importante deste processo foi a definição de um conjunto de métricas para a análise comparativa dos algoritmos. As características individuais de rastreamento de cada um deles trouxeram bons resultados em alguns dos cinco cenários utilizados. Porém, no geral, o rastreador que apresentou os melhores resultados foi o KLT. Uma análise detalhada sobre os resultados desses algoritmos quando empregados para reconstrução 3D é apresentada
16
Prisacariu, Victor Adrian. "Shape knowledge for segmentation and tracking." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:68dd7205-219a-45e1-830d-f55e530ed8aa.
Анотація:
The aim of this thesis is to provide methods for 2D segmentation and 2D/3D tracking, that are both fast and robust to imperfect image information, as caused for example by occlusions, motion blur and cluttered background. We do this by combining high level shape information with simultaneous segmentation and tracking. We base our work on the assumption that the space of possible 2D object shapes can be either generated by projecting down known rigid 3D shapes or learned from 2D shape examples. We minimise the discrimination between statistical foreground and background appearance models with respect to the parameters governing the shape generative process (the 6 degree-of-freedom 3D pose of the 3D shape or the parameters of the learned space). The foreground region is delineated by the zero level set of a signed distance function, and we define an energy over this region and its immediate background surroundings based on pixel-wise posterior membership probabilities. We obtain the differentials of this energy with respect to the parameters governing shape and conduct searches for the correct shape using standard non-linear minimisation techniques. This methodology first leads to a novel rigid 3D object tracker. For a known 3D shape, our optimisation here aims to find the 3D pose that leads to the 2D projection that best segments a given image. We extend our approach to track multiple objects from multiple views and propose novel enhancements at the pixel level based on temporal consistency. Finally, owing to the per pixel nature of much of the algorithm, we support our theoretical approach with a real-time GPU based implementation. We next use our rigid 3D tracker in two applications: (i) a driver assistance system, where the tracker is augmented with 2D traffic sign detections, which, unlike previous work, allows for the relevance of the traffic signs to the driver to be gauged and (ii) a robust, real time 3D hand tracker that uses data from an off-the-shelf accelerometer and articulated pose classification results from a multiclass SVM classifier. Finally, we explore deformable 2D/3D object tracking. Unlike previous works, we use a non-linear and probabilistic dimensionality reduction, called Gaussian Process Latent Variable Models, to learn spaces of shape. Segmentation becomes a minimisation of an image-driven energy function in the learned space. We can represent both 2D and 3D shapes which we compress with Fourier-based transforms, to keep inference tractable. We extend this method by learning joint shape-parameter spaces, which, novel to the literature, enable simultaneous segmentation and generic parameter recovery. These can describe anything from 3D articulated pose to eye gaze. We also propose two novel extensions to standard GP-LVM: a method to explore the multimodality in the joint space efficiently, by learning a mapping from the latent space to a space that encodes the similarity between shapes and a method for obtaining faster convergence and greater accuracy by use of a hierarchy of latent embeddings.
17
Söderberg, Anton. "Myokardpåverkan hos förstagradssläktingar till hypertrofa kardiomyopatiprobander." Thesis, Umeå universitet, Biomedicinsk laboratorievetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-57967.
18
Heydarian, Arsalan. "Automated Vision-Based Tracking and Action Recognition of Earthmoving Construction Operations." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76761.
Анотація:
The current practice of construction productivity and emission monitoring is performed by either manual stopwatch studies which are significantly labor intensive and subject to human errors, or by the use of RFID and GPS tracking devices which may be costly and impractical. To address these limitations, a novel computer vision based method for automated 2D tracking, 3D localization, and action recognition of construction equipment from different camera viewpoints is presented. In the proposed method, a new algorithm based on Histograms of Oriented Gradients and hue-saturation Colors (HOG+C) is used for 2D tracking of the earthmoving equipment. Once the equipment is detected, using a Direct Linear Transformation followed by a non-linear optimization, their positions are localized in 3D. In order to automatically analyze the performance of these operations, a new algorithm to recognize actions of the equipment is developed. First, a video is represented as a collection of spatio-temporal features by extracting space-time interest points and describing each with a Histogram of Oriented Gradients (HOG). The algorithm automatically learns the distributions of these features by clustering their HOG descriptors. Equipment action categories are then learned using a multi-class binary Support Vector Machine (SVM) classifier. Given a novel video sequence, the proposed method recognizes and localizes equipment actions. The proposed method has been exhaustively tested on 859 videos from earthmoving operations. Experimental results with an average accuracy of 86.33% and 98.33% for excavator and truck action recognition respectively, reflect the promise of the proposed method for automated performance monitoring.Master of Science
19
Rieper, Karl [Verfasser]. "Echokardiographische Verlaufsuntersuchungen von Patienten mit Systemischer Sklerose mittels 2D Speckle Tracking des linken Ventrikels / Karl Rieper." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1126504874/34.
20
Kaiser, Felix [Verfasser]. "Stellenwert der myokardialen 2D-Speckle Tracking Deformationsanalyse bei der Patientenauswahl für eine biventrikuläre Resynchronisationstherapie / Felix Kaiser." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1222588781/34.
21
Putri, Dian Kemala. "Comprehension of complex animation : cueing, segmentation and 2D / 3D presentations." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00795026.
Анотація:
The goal of our studies was to test the effect of segmentation, cueing, and 2D/3D presentations to foster complex animation rocessing. The material was an upright mechanical piano system. We used an eye tracking system which provides information about learners' attention direction during the animation processing. We analyzed the effect of the format presentations and the eye movements during learning. Based on animation and multimedia research background, four experiments were conducted. In the first experiment the effect of the presentation of simplified external representations on learning from complex animation was investigated. Experiment two and three aimed at studying the cognitive processes involved in learning to complex mechanism system with new cueing techniques with spatial-temporal colored tokens. In the fourth experiment, 2D and 3D presentation of the same animated content were compared. Results of these experiments showed that (1) the use of a dual format presentation is better for developing a dynamic mental model from the animation than a single format, (2) the signaling strategies using cued tokens of dual format can guide efficiently learner's building of mental model and can enhance learner's comprehension of complex system, (3) a sequential format presentation followed by an animation format presentation helps the learner to understand the key stages of a dynamic process and to create a high quality mental model, (4) 3D animation presentation is better than 2D animation presentation to direct attention on relevant component of the animation. For depth processing, comprehension with 3D animation presentation is better than 2D animation format. Eye tracking measures provided insights into how people understood and learned complex systems. The analysis of eye tracking also contributed to the understanding of the subject's perceptual processing during learning. Overall, results provide a significant contribution in the field of learning with complex animation. Recommendations in the ergonomics area for the design of animations are proposed.
22
Boui, Marouane. "Détection et suivi de personnes par vision omnidirectionnelle : approche 2D et 3D." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLE009/document.
Анотація:
Dans cette thèse, nous traiterons du problème de la détection et du suivi 3D de personnes dans des séquences d'images omnidirectionnelles, dans le but de réaliser des applications permettant l'estimation de pose 3D. Ceci nécessite, la mise en place d'un suivi stable et précis de la personne dans un environnement réel. Dans le cadre de cette étude, on utilisera une caméra catadioptrique composée d'un miroir sphérique et d'une caméra perspective. Ce type de capteur est couramment utilisé dans la vision par ordinateur et la robotique. Son principal avantage est son large champ de vision qui lui permet d'acquérir une vue à 360 degrés de la scène avec un seul capteur et en une seule image. Cependant, ce capteur va engendrer des distorsions importantes dans les images, ne permettant pas une application directe des méthodes classiquement utilisées en vision perspective. Cette thèse traite de deux approches de suivi développées durant cette thèse, qui permettent de tenir compte de ces distorsions. Elles illustrent le cheminement suivi par nos travaux, nous permettant de passer de la détection de personne à l'estimation 3D de sa pose. La première étape de nos travaux a consisté à mettre en place un algorithme de détection de personnes dans les images omnidirectionnelles. Nous avons proposé d'étendre l'approche conventionnelle pour la détection humaine en image perspective, basée sur l'Histogramme Orientés du Gradient (HOG), pour l'adapter à des images sphériques. Notre approche utilise les variétés riemanniennes afin d'adapter le calcul du gradient dans le cas des images omnidirectionnelles. Elle utilise aussi le gradient sphérique pour le cas les images sphériques afin de générer notre descripteur d'image omnidirectionnelle. Par la suite, nous nous sommes concentrés sur la mise en place d'un système de suivi 3D de personnes avec des caméras omnidirectionnelles. Nous avons fait le choix de faire du suivi 3D basé sur un modèle de la personne avec 30 degrés de liberté car nous nous sommes imposés comme contrainte l'utilisation d'une seule caméra catadioptriqueIn this thesis we will handle the problem of 3D people detection and tracking in omnidirectional images sequences, in order to realize applications allowing3D pose estimation, we investigate the problem of 3D people detection and tracking in omnidirectional images sequences. This requires a stable and accurate monitoring of the person in a real environment. In order to achieve this, we will use a catadioptric camera composed of a spherical mirror and a perspective camera. This type of sensor is commonly used in computer vision and robotics. Its main advantage is its wide field of vision, which allows it to acquire a 360-degree view of the scene with a single sensor and in a single image. However, this kind of sensor generally generates significant distortions in the images, not allowing a direct application of the methods conventionally used in perspective vision. Our thesis contains a description of two monitoring approaches that take into account these distortions. These methods show the progress of our work during these three years, allowing us to move from person detection to the 3Destimation of its pose. The first step of this work consisted in setting up a person detection algorithm in the omnidirectional images. We proposed to extend the conventional approach for human detection in perspective image, based on the Gradient-Oriented Histogram (HOG), in order to adjust it to spherical images. Our approach uses the Riemannian varieties to adapt the gradient calculation for omnidirectional images as well as the spherical gradient for spherical images to generate our omnidirectional image descriptor
23
Tokatli, Aykut. "3d Hand Tracking In Video Sequences." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12606461/index.pdf.
Анотація:
The use of hand gestures provides an attractive alternative to cumbersome interface devices such as keyboard, mouse, joystick, etc. Hand tracking has a great potential as a tool for better human-computer interaction by means of communication in a more natural and articulate way. This has motivated a very active research area concerned with computer vision-based analysis and interpretation of hand gestures and hand tracking.
In this study, a real-time hand tracking system is developed. Mainly, it is image-based hand tracking and based on 2D image information. For separation and identification of finger parts, coloured markers are used. In order to obtain 3D tracking, a stereo vision approach is used where third dimension is obtained by depth information. In order to see results in 3D, a 3D hand model is developed and Java 3D is used as the 3D environment.
Tracking is tested on two different types of camera: a cheap USB web camera and Sony FCB-IX47AP camera, connected to the Matrox Meteor frame grabber with a standard Intel Pentium based personal computer. Coding is done by Borland C++ Builder 6.0 and Intel Image Processing and Open Source Computer Vision (OpenCV) library are used as well. For both camera types, tracking is found to be robust and efficient where hand tracking at ~8 fps could be achieved.
Although the current progress is encouraging, further theoretical as well as computational advances are needed for this highly complex task of hand tracking.
24
Arredal, Martin. "Eye Tracking’s Impact on Player Performance and Experience in a 2D Space Shooter Video Game." Thesis, Blekinge Tekniska Högskola, Institutionen för datavetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17823.
Анотація:
Background. Although a growing market, most of the commercially available gamestoday that features eye tracking support is rendered in a 3D perspective. Games ren-dered in 2D have seen little support for eye trackers from developers. By comparing the differences in player performance and experience between an eye tracker and acomputer mouse when playing a classic 2D genre: space shooter, this thesis aim tomake an argument for the implementation of eye tracking in 2D video games. Objectives. Create a 2D space shooter video game where movement will be handledthrough a keyboard but the input method for aiming will alter between a computermouse and an eye tracker. Methods. Using a Tobii EyeX eye tracker, an experiment was conducted with fif-teen participants. To measure their performance, three variables was used: accuracy,completion time and collisions. The participants played two modes of a 2D spaceshooter video game in a controlled environment. Depending on which mode wasplayed, the input method for aiming was either an eye tracker or a computer mouse.The movement was handled using a keyboard for both modes. When the modes hadbeen completed, a questionnaire was presented where the participants would ratetheir experience playing the game with each input method. Results. The computer mouse had a better performance in two out of three per-formance variables. On average the computer mouse had a better accuracy andcompletion time but more collisions. However, the data gathered from the question-naire shows that the participants had on average a better experience when playingwith an eye tracker Conclusions. The results from the experiment shows a better performance for par-ticipants using the computer mouse, but participants felt more immersed with the eyetracker and giving it a better score on all experience categories. With these results,this study hope to encourage developers to implement eye tracking as an interactionmethod for 2D video games. However, future work is necessary to determine if theexperience and performance increase or decrease as the playtime gets longer.
25
Dasgupta, Sumantra. "Reconstruction of 3D rigid body motion in a virtual environment from a 2D image sequence." Thesis, [College Station, Tex. : Texas A&M University, 2004. http://hdl.handle.net/1969.1/469.
Анотація:
Thesis (M.S.)--Texas A&M University, 2003."Major Subject: Electrical Engineering" Title from author supplied metadata (record created on Jul. 18, 2005.) Vita. Abstract. Includes bibliographical references.
26
Fransson, Jonatan, and Teemu Hiiriskoski. "Measuring Immersion and Enjoyment in a 2D Top-Down Game by Replacing the Mouse Input with Eye Tracking." Thesis, Blekinge Tekniska Högskola, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18258.
Анотація:
Background. Eye tracking has been evaluated and tried in different 2D settings for research purposes. Most commercial games that are using eye tracking use it as an assistive extra input method and are focused around third or first person. There are few 2D games developed with eye tracking as an input method. This thesis aims to test the use of eye tracking as a replacement input method with a chosen set of mechanics for the purpose of playing a 2D top-down game with eye tracking as the main input method. Objectives. To test eye tracking in a 2D top-down game and use it as a replacement input method for the mouse in a novel effort to evaluate immersion and enjoyment. Method. To conduct this study the Tobii 4C eye tracker is used as the replacement peripheral in a 2D game prototype developed for the study. The game prototype is developed with the Unity game engine which the participants played through twice with a different input mode each time. Once with a keyboard and mouse and a second time with a keyboard and an eye tracker. The participants played different modes in alternating order to not sway the results. For the game prototype three different mechanics were implemented, to aim, search for hidden items and remove shadows. To measure immersion and enjoyment an experiment was carried out in a controlled manner, letting participants play through the game prototype and evaluating their experience. To evaluate the experience the participants answered a questionnaire with 12 questions relating to their perceived immersion and a small interview with 5 questions about their experience and perceived enjoyment. The study had a total of 12 participants. Results. The results from the data collected through the experiment indicate that the participants enjoyed and felt more involvement in the game, 10 out of 12 participants answering that they felt more involved with the game using eye tracking compared to the mouse. Analyzing the interviews, the participants stated that eye tracking made the game more difficult and less natural to control compared to the mouse. There is a potential problem that might sway the results toward eye tracking, most participants stated that eye tracking is a new experience and none of the participants had used it to play video games before. Conclusions. The results from the questionnaire prove the hypothesis with statistics, with a p-value of 0.02 < 5% for both increased involvement and enjoyment using eye tracking. Although the result might be biased due to the participant's inexperience with eye tracking in video games. Most of the participants reacted positively towards eye tracking with the most common reason being that it was a new experience to them.
27
GRITAI, ALEXEI. "MULTI-VIEW GEOMETRIC CONSTRAINTS FOR HUMAN ACTION RECOGNITION AND TRACKING." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4032.
Анотація:
Human actions are the essence of a human life and a natural product of the human mind. Analysis of human activities by a machine has attracted the attention of many researchers. This analysis is very important in a variety of domains including surveillance, video retrieval, human-computer interaction, athlete performance investigation, etc. This dissertation makes three major contributions to automatic analysis of human actions. First, we conjecture that the relationship between body joints of two actors in the same posture can be described by a 3D rigid transformation. This transformation simultaneously captures different poses and various sizes and proportions. As a consequence of this conjecture, we show that there exists a fundamental matrix between the imaged positions of the body joints of two actors, if they are in the same posture. Second, we propose a novel projection model for cameras moving at a constant velocity in 3D space, \emph cameras, and derive the Galilean fundamental matrix and apply it to human action recognition. Third, we propose a novel use for the invariant ratio of areas under an affine transformation and utilizing the epipolar geometry between two cameras for 2D model-based tracking of human body joints. In the first part of the thesis, we propose an approach to match human actions using semantic correspondences between human bodies. These correspondences are used to provide geometric constraints between multiple anatomical landmarks ( e.g. hands, shoulders, and feet) to match actions observed from different viewpoints and performed at different rates by actors of differing anthropometric proportions. The fact that the human body has approximate anthropometric proportion allows for innovative use of the machinery of epipolar geometry to provide constraints for analyzing actions performed by people of different anthropometric sizes, while ensuring that changes in viewpoint do not affect matching. A novel measure in terms of rank of matrix constructed only from image measurements of the locations of anatomical landmarks is proposed to ensure that similar actions are accurately recognized. Finally, we describe how dynamic time warping can be used in conjunction with the proposed measure to match actions in the presence of nonlinear time warps. We demonstrate the versatility of our algorithm in a number of challenging sequences and applications including action synchronization , odd one out, following the leader, analyzing periodicity etc. Next, we extend the conventional model of image projection to video captured by a camera moving at constant velocity. We term such moving camera Galilean camera. To that end, we derive the spacetime projection and develop the corresponding epipolar geometry between two Galilean cameras. Both perspective imaging and linear pushbroom imaging form specializations of the proposed model and we show how six different ``fundamental" matrices including the classic fundamental matrix, the Linear Pushbroom (LP) fundamental matrix, and a fundamental matrix relating Epipolar Plane Images (EPIs) are related and can be directly recovered from a Galilean fundamental matrix. We provide linear algorithms for estimating the parameters of the the mapping between videos in the case of planar scenes. For applying fundamental matrix between Galilean cameras to human action recognition, we propose a measure that has two important properties. First property makes it possible to recognize similar actions, if their execution rates are linearly related. Second property allows recognizing actions in video captured by Galilean cameras. Thus, the proposed algorithm guarantees that actions can be correctly matched despite changes in view, execution rate, anthropometric proportions of the actor, and even if the camera moves with constant velocity. Finally, we also propose a novel 2D model based approach for tracking human body parts during articulated motion. The human body is modeled as a 2D stick figure of thirteen body joints and an action is considered as a sequence of these stick figures. Given the locations of these joints in every frame of a model video and the first frame of a test video, the joint locations are automatically estimated throughout the test video using two geometric constraints. First, invariance of the ratio of areas under an affine transformation is used for initial estimation of the joint locations in the test video. Second, the epipolar geometry between the two cameras is used to refine these estimates. Using these estimated joint locations, the tracking algorithm determines the exact location of each landmark in the test video using the foreground silhouettes. The novelty of the proposed approach lies in the geometric formulation of human action models, the combination of the two geometric constraints for body joints prediction, and the handling of deviations in anthropometry of individuals, viewpoints, execution rate, and style of performing action. The proposed approach does not require extensive training and can easily adapt to a wide variety of articulated actions.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Science PhD
28
Mahmoud, Mohamed. "Parking Map Generation and Tracking Using Radar : Adaptive Inverse Sensor Model." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-167084.
Анотація:
Radar map generation using binary Bayes filter or what is commonly known as Inverse Sensor Model; which translates the sensor measurements into grid cells occupancy estimation, is a classical problem in different fields. In this work, the focus will be on development of Inverse Sensor Model for parking space using 77 GHz FMCW (Frequency Modulated Continuous Wave) automotive radar, that can handle different environment geometrical complexity in a parking space. There are two main types of Inverse Sensor Models, where each has its own assumption about the sensor noise. One that is fixed and is similar to a lookup table, and constructed based on combination of sensor-specific characteristics, experimental data and empirically-determined parameters. The other one is learned by using ground truth labeling of the grid map cell, to capture the desired Inverse Sensor Model. In this work a new Inverse Sensor Model is proposed, that make use of the computational advantage of using fixed Inverse Sensor Model and capturing desired occupancy estimation based on ground truth labeling. A derivation of the occupancy grid mapping problem using binary Bayes filtering would be performed from the well known SLAM (Simultaneous Localization and Mapping) problem, followed by presenting the Adaptive Inverse Sensor Model, that uses fixed occupancy estimation but with adaptive occupancy shape estimation based on statistical analysis of the radar measurements distribution across the acquisition environment. A prestudy of the noise nature of the radar used in this work is performed, to have a common Inverse Sensor Model as a benchmark. Then the drawbacks of such Inverse Sensor Model would be addressed as sub steps of Adaptive Inverse Sensor Model, to be able to haven an optimal grid map occupancy estimator. Finally a comparison between the generated maps using the benchmark and the adaptive Inverse Sensor Model will take place, to show that under the fulfillment of the assumptions of the Adaptive Inverse Sensor Model, the Adaptive Inverse Sensor Model can offer a better visual appealing map to that of the benchmark.
29
Trache, Marian Tudor [Verfasser], Andreas [Akademischer Betreuer] Hagendorff, Gerhard [Gutachter] Schuler, and Fabian [Gutachter] Knebel. "The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate / Marian Tudor Trache ; Gutachter: Gerhard Schuler, Fabian Knebel ; Betreuer: Andreas Hagendorff." Leipzig : Universitätsbibliothek Leipzig, 2016. http://d-nb.info/1240481381/34.
30
Izem, Omar. "Cinétique de la fonction et de la mécanique ventriculaire gauche lors de la transition repos-effort : èvaluation par échocardiographie en mode 2D-strain." Thesis, Avignon, 2017. http://www.theses.fr/2017AVIG0714/document.
Анотація:
Initiée par les travaux des lauréats du prix Nobel Krogh et Hill l’étude de l’adaptation du système cardiorespiratoire lors de la transition du repos à l’exercice représente un champ majeur en physiologie de l’exercice. En début d’effort, la consommation d’oxygène (VO2) doit rapidement s’adapter afin de minimiser le déficit en dioxygène (O2), les perturbations intracellulaires et par conséquent optimiser la performance. Pendant cette phase dite « cardiodynamique » le ventricule gauche (VG) doit rapidement augmenter l’apport en O2 aux muscles actifs. Le volume d’éjection systolique (VES) et les nombreux paramètres qui le conditionnent doivent aussi rapidement s’adapter malgré une réduction très importante de la durée de diastole. Comment le VG parvient-il à relever ce défi dans les premières minutes de l’exercice et comment ces différents paramètres interagissent ? L’objectif de ce travail de thèse est de répondre à ces questions en combinant l’utilisation des dernières avancées de l’échocardiographie en mode « Speckle Tracking » (STE), permettant d’apprécier finement la fonction myocardique régionale grâce à l’évaluation de la mécanique du VG, avec une approche originale caractérisée par des enregistrements à intervalles réguliers proches au cours de répétitions d’épreuves à charges constantes (épreuves dites « rectangulaires »). Une première partie va consister à décrire finement les cinétiques cardiaques chez le sujet jeune actif, alors qu’une deuxième partie s’attachera à évaluer l’impact de l’entraînement aérobie chez des cyclistes de très bon niveau rapportant de nombreuses années de pratique. Les résultats mettent en évidence que la fonction diastolique et ses mécanismes sous-jacents jouent un rôle clé dans l’adaptation du VES à l’exercice. En permettant l’augmentation de la vitesse de remplissage, la pression de remplissage et la relaxation favorisent l’adaptation du VES dans la première minute. L’adaptation de la vitesse de détorsion jusqu’à 120s prolonge l’adaptation de la vitesse de remplissage et permet le maintien du VES au-delà de la première minute. Par ailleurs, nos résultats indiquent que l’entraînement aérobie induit une adaptation du VES plus importante grâce à une amélioration de la vitesse et du débit de remplissage du VG. Ces améliorations sont le résultat d’une adaptation plus rapide et plus importante de la relaxation à la base et d’une adaptation plus importante de la vitesse de détorsion. Ce travail de thèse basé sur l’étude de la mécanique cardiaque à l’exercice d’intensité modérée a permis de montrer le rôle clé de la diastole, et plus particulièrement de la détorsion du VG, dans l’adaptation rapide du VES ainsi que son amélioration chez le sportif aérobie. En perspective, il serait intéressant d’étudier les cinétiques cardiaques à des intensités d’exercice supérieures ou dans des populations qui présentent des intolérances à l'effortInitiated by the pioneering works of Nobel laureates Krogh and Hill, the study of cardiorespiratory system adaptation from rest to dynamic exercise represents a major field in exercise physiology. Oxygen uptake (VO2) has to abruptly increase in order to optimize exercise performance and tolerance by minimizing oxygen deficit and intracellular perturbations. During this “cardiodynamic” phase the LV has to abruptly increase oxygen delivery to mitochondria of active muscles. The stroke volume (SV) and its underlying mechanisms have to rapidly increase despite an important reduction of LV diastolic time. How do LV mechanics address this challenge at the onset of exercise and how do these different factors interact? Therefore, the aim of the present thesis is to answer to these questions by combining the use of latest advances in speckle tracking echocardiography (STE), which allow accurate assessment of regional myocardial function by the evaluation of LV mechanics, with an original approach based on the repetition of five similar constant work-load exercises, each of them being used to record different parameters. The first part give an accurate description of LV kinetics in young healthy active males whereas the second part focus on the evaluation of endurance training effect in well-trained cyclists. Our result highlight the key role of diastolic function and its underlying mechanisms in SV adaptation to exercise. In the first 60s, LV filling pressure and relaxation promote increase of LV filling velocity and hence SV adaptation. Beyond the first 60s, peak untwisting rate continue to increase until 120s allowing for a further increase of LV filling velocity involving SV maintenance. Furthermore, our results indicate that endurance training involve more important adaptation of SV by the improvement of LV filling velocity and filling rate. These improvement are the result of faster and higher adaptation of relaxation at the base and untwisting rate. This thesis based on the assessment of cardiac mechanic at moderate intensity exercise show the key role of diastole and more specifically LV untwist in the fast adaptation of SV and its improvement with endurance training. It would be interesting to study cardiac kinetics in heavy exercise and in pathological population presenting exercise intolerance
31
Qiu, Xuchong. "2D and 3D Geometric Attributes Estimation in Images via deep learning." Thesis, Marne-la-vallée, ENPC, 2021. http://www.theses.fr/2021ENPC0005.
Анотація:
La perception visuelle d'attributs géométriques (ex. la translation, la rotation, la taille, etc.) est très importante dans les applications robotiques. Elle permet à un système robotique d'acquérir des connaissances sur son environnement et peut fournir des entrées pour des tâches telles que la localisation d'objets, la compréhension de scènes et la planification de trajectoire. Le principal objectif de cette thèse est d'estimer la position et l'orientation d'objets d'intérêt pour des tâches de manipulation robotique. En particulier, nous nous intéressons à la tâche de bas niveau d'estimation de la relation d'occultation, afin de mieux pouvoir discriminer objets différents, et aux tâches de plus haut niveau de suivi visuel d'objets et d'estimation de leur position et orientation. Le premier axe d'étude est le suivi (tracking) d'un objet d'intérêt dans une vidéo, avec des locations et tailles correctes. Tout d'abord, nous étudions attentivement le cadre du suivi d'objet basé sur des filtres de corrélation discriminants et proposons d'exploiter des informations sémantiques à deux niveaux~: l'étape d'encodage des caractéristiques visuelles et l'étape de localisation de la cible. Nos expériences démontrent que l'usage de la sémantique améliore à la fois les performances de la localisation et de l'estimation de taille de l'objet suivi. Nous effectuons également des analyses pour comprendre les cas d'échec. Le second axe d'étude est l'utilisation d'informations sur la forme des objets pour améliorer la performance de l'estimation de la pose 6D des objets et de son raffinement. Nous proposons d'estimer avec un modèle profond les projections 2D de points 3D à la surface de l'objet, afin de pouvoir calculer la pose 6D de l'objet. Nos résultats montrent que la méthode que nous proposons bénéficie du grand nombre de correspondances de points 3D à 2D et permet d'obtenir une meilleure précision des estimations. Dans un deuxième temps, nous étudions les contraintes des méthodes existantes pour raffiner la pose d'objets et développons une méthode de raffinement des objets dans des contextes arbitraires. Nos expériences montrent que nos modèles, entraînés sur des données réelles ou des données synthétiques générées, peuvent raffiner avec succès les estimations de pose pour les objets dans des contextes quelconques. Le troisième axe de recherche est l'étude de l'occultation géométrique dans des images, dans le but de mieux pouvoir distinguer les objets dans la scène. Nous formalisons d'abord la définition de l'occultation géométrique et proposons une méthode pour générer automatiquement des annotations d'occultation de haute qualité. Ensuite, nous proposons une nouvelle formulation de la relation d'occultation (abbnom) et une méthode d'inférence correspondante. Nos expériences sur les jeux de tests pour l'estimation d'occultations montrent la supériorité de notre formulation et de notre méthode. Afin de déterminer des discontinuités de profondeur précises, nous proposons également une méthode de raffinement de cartes de profondeur et une méthode monoculaire d'estimation de la profondeur en une étape. En utilisant l'estimation de relations d'occultation comme guide, ces deux méthodes atteignent les performances de l'état de l'art. Toutes les méthodes que nous proposons s'appuient sur la polyvalence et la puissance de l'apprentissage profond. Cela devrait faciliter leur intégration dans le module de perception visuelle des systèmes robotiques modernes. Outre les avancées méthodologiques mentionnées ci-dessus, nous avons également rendu publiquement disponibles des logiciels (pour l'estimation de l'occlusion et de la pose) et des jeux de données (informations de haute qualité sur les relations d'occultation) afin de contribuer aux outils offerts à la communauté scientifiqueThe visual perception of 2D and 3D geometric attributes (e.g. translation, rotation, spatial size and etc.) is important in robotic applications. It helps robotic system build knowledge about its surrounding environment and can serve as the input for down-stream tasks such as motion planning and physical intersection with objects.The main goal of this thesis is to automatically detect positions and poses of interested objects for robotic manipulation tasks. In particular, we are interested in the low-level task of estimating occlusion relationship to discriminate different objects and the high-level tasks of object visual tracking and object pose estimation.The first focus is to track the object of interest with correct locations and sizes in a given video. We first study systematically the tracking framework based on discriminative correlation filter (DCF) and propose to leverage semantics information in two tracking stages: the visual feature encoding stage and the target localization stage. Our experiments demonstrate that the involvement of semantics improves the performance of both localization and size estimation in our DCF-based tracking framework. We also make an analysis for failure cases.The second focus is using object shape information to improve the performance of object 6D pose estimation and do object pose refinement. We propose to estimate the 2D projections of object 3D surface points with deep models to recover object 6D poses. Our results show that the proposed method benefits from the large number of 3D-to-2D point correspondences and achieves better performance. As a second part, we study the constraints of existing object pose refinement methods and develop a pose refinement method for objects in the wild. Our experiments demonstrate that our models trained on either real data or generated synthetic data can refine pose estimates for objects in the wild, even though these objects are not seen during training.The third focus is studying geometric occlusion in single images to better discriminate objects in the scene. We first formalize geometric occlusion definition and propose a method to automatically generate high-quality occlusion annotations. Then we propose a new occlusion relationship formulation (i.e. abbnom) and the corresponding inference method. Experiments on occlusion reasoning benchmarks demonstrate the superiority of the proposed formulation and method. To recover accurate depth discontinuities, we also propose a depth map refinement method and a single-stage monocular depth estimation method.All the methods that we propose leverage on the versatility and power of deep learning. This should facilitate their integration in the visual perception module of modern robotic systems.Besides the above methodological advances, we also made available software (for occlusion and pose estimation) and datasets (of high-quality occlusion information) as a contribution to the scientific community
32
Parisot, Pascaline. "Suivi d’objets dans des séquences d’images de scènes déformables : de l’importance des points d’intérêt et du maillage 2D." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT012H/document.
Анотація:
Nous abordons le suivi d’objets dans des séquences d’images de scènes déformables selon deux axes de recherche. Il s’agit de déterminer les transformations d’un objet, d’une image à l’autre, lorsque celui-ci s’est éventuellement déformé ou déplacé et lorsque le point de vue de la caméra a éventuellement été modifié (déplacement, zoom...). Pour cela, nous nous sommes inspirés de l’algorithme de Jurie et Dhome qui permet de suivre un objet plan indéformable. D’une part, nous en améliorons les performances. D’autre part, nous le généralisons au cas d’objets déformables. Le premier axe de recherche consiste à améliorer les performances de l’algorithme de Jurie et Dhome en termes de précision et robustesse. Le suivi s’appuie sur un ensemble de points d’intérêt, dont dépendent fortement les performances. Ces points d’intérêt sont issus d’une sélection des points obtenus par des détecteurs reconnus, à savoir SIFT, KLT, SUSAN, HARRIS et MORAVEC. Nous avons étudié et mis en oeuvre, sur différentes classes d’images, des heuristiques de sélection fondées sur des approches statistique et algébrique. Nous montrons : – qu’il n’existe pas de détecteur universel, – que l’approche statistique est à privilégier dans tous les cas. Le second axe de recherche est une proposition d’un nouvel algorithme de suivi s’appuyant sur le maillage 2D des images de la séquence. Cet algorithme généralise celui de Jurie et Dhome aux scènes déformables. Il repose sur : – des transformations élémentaires (nodales) du maillage, directes et inverses, que nous avons caractérisées tant d’un point de vue géométrique qu’analytique, – l’utilisation des coordonnées barycentriques généralisées pour approcher la composition de deux transformations d’un maillage. Cet algorithme donne des résultats similaires à celui d’appariement hexagonal de Nakaya et Harashima tout en étant plus rapideWe deal with object tracking in videos of non-rigid scenes with two main purposes. We aim at determining the transformations of an object, from one frame to the next, when it may be distorted or moved and when the camera focus may change (movement, zoom...). To do this, we were inspired by the Jurie and Dhome algorithm, which enables the tracking of plane rigid objects. On the one hand, we improve its performance. On the other hand, we generalize it to non-rigid objects. The first goal consists in improving the performance of the Jurie and Dhome algorithm, in terms of accuracy and robustness. The tracking is based on a set of interest points, which has a great effect on the algorithm’s performance. These interest points come from a selection among the points extracted with some common detectors: SIFT, KLT, SUSAN, HARRIS, and MORAVEC.With various pictures classes, we have studied and implemented some selection heuristics based on statistical or algebraic approaches. We show that : • there is no universal detector, • the statistical approach is the best in all cases. The second goal is a proposal of a new tracking algorithm based on a 2D mesh of the video frames. This algorithm generalizes the Jurie and Dhome one for non-rigid scenes. It is based on : • elementary (nodal), direct or inverse, mesh transformations that we geometrically and analytically characterize, • generalized barycentric coordinates to approximate the composition of two mesh transformations. This algorithm gives similar results to the hexagonal matching algorithm of Nakaya and Harashima while being faster
33
Beacon, Jillian. "Assessing 2D and 3D Motion Tracking Technologies for Measuring the Immediate Impact of Feldenkrais Training on the Playing Postures of Pianists." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33125.
Анотація:
The Feldenkrais Method of somatic education has become popular with pianists for improving ease of motion and musculoskeletal health. This thesis contains three studies investigating motion-tracking technologies as means to objectively assess the impact of Feldenkrais training on pianist posture. The first study investigates the accuracy and reliability of Dartfish 2D motion tracking software. Results indicate that Dartfish tracking error is within +/- 0.25 centimeters. The second study uses Dartfish to track head, shoulder, and spine positions of 15 pianists during performance before and after receiving a Feldenkrais Functional Integration Lesson. Comparisons of pre- and post-test measurements indicate no group trends in posture change. However, intriguing changes to movement quality in the head and torso were observable for two participants. The third study compares tracking quality of Dartfish and the Microsoft Kinect for the head, shoulders, and arms of four pianists attending a weeklong Feldenkrais workshop. Results reveal frequent tracking errors with the Kinect sensor, making it unsuitable to measure the impact of somatic training on pianist posture.
34
Nagel, Deborah. "Die Auswirkungen des α2 -Adrenozeptor-Agonisten Romifidin auf die Myokardfunktion des Pferdes, gemessen mit der Gewebedopplerechokardiographie und dem 2D Speckle Tracking". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-142312.
35
Dahlgren, Mikael. "Object Selection by Relative Hand to Cursor Mapping : Design and Evaluation of a 2D-Object Selection Technique for Hand Tracking in Virtual Environments." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292107.
Анотація:
Hand and tracker jitter negatively affect performance with ray-casting in virtual environments, making it difficult to acquire small objects which require high levels of precision. This study evaluates an alternative target acquisition technique for 2D-interfaces in virtual environments with relative hand-to-cursor mapping. Trade-offs between the relative hand-to-cursor mapping and ray-casting are explored in comparative evaluation, utilizing Fitts's law, SUS-surveys and interviews. The results demonstrate that relative hand-to-cursor mapping performs equal to ray-casting while also allowing higher precision in certain selection tasks.Strålföljning påverkas negativt av darrning i händer och spårteknik i virtuella miljöer vilket gör det svårt att markera objekt som kräver hög precision. Denna studie utvärderar en alternativ teknik till strålföljning for objektmarkering i 2D-granssnitt i virtuella miljöer kallad relativ hand till musmarkör mappning. Avvägning mellan dessa två tekniker utvärderas i en jämförande studie med hjälp av Fitts's lag, SUS-undersökning och intervjuer. Resultaten demonstrerar att relativ hand till murmarkor mappning presterar jämförbart med strålföljning och tillåter samtidigt högre precision i särskilda objektmarkeringsuppgifter.
36
Önügören, Onur [Verfasser]. "Assessment of long axis ventricular function in the fetal heart based on 2D grey scale image processing with a tissue tracking algorithm / Onur Önügören." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2011. http://d-nb.info/1025353986/34.
37
Nagel, Deborah Verfasser], та Heidrun [Akademischer Betreuer] [Gehlen. "Die Auswirkungen des α2 -Adrenozeptor-Agonisten Romifidin auf die Myokardfunktion des Pferdes, gemessen mit der Gewebedopplerechokardiographie und dem 2D Speckle Tracking / Deborah Nagel. Betreuer: Heidrun Gehlen". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1022523368/34.
38
Spriestersbach, Hendrik [Verfasser]. "2d-Speckle-Tracking basierter Strain und Strain Rate zur Früherkennung Anthrazyklin-induzierter systolischer Funktionsstörungen des linken Ventrikels : eine Machbarkeitsstudie in einer konsekutiven Reihe ambulanter Patienten / Hendrik Spriestersbach." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1070819581/34.
39
Gao, Bo. "Contribution à la synthèse de commandes référencées vision 2D multi-critères." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00119789.
Анотація:
Cette thèse concerne la synthèse de lois commande référencées vision 2D, multi-critères, pour le positionnement, par rapport à une cible fixe ou mobile, d'une caméra orientable en lacet en mouvement dans le plan horizontal. La fréquence et la qualité des informations délivrées par les caméras CCD qui équipent aujourd'hui les robots rend en effet possible l'alimentation directe des boucles de commande à partir des mesures visuelles de l'environnement. Le modèle considéré est défini dans le cadre du formalisme des fonctions de tâches et s'appuie sur la notion de torseur d'interaction qui permet de relier le mouvement de la caméra à la variation des indices visuels. L'objectif de ce travail est de proposer des lois de commandes permettant de stabiliser la caméra sur la base des informations bidimensionnelles issues de l'image, en tenant compte de l'incertitude sur la profondeur des points de la cible, des contraintes de visibilité et des limites en amplitude sur la vitesse et l'accélération de la caméra. La méthode proposée met en oeuvre des techniques de commande avancées. Elle est basée sur la satisfaction d'une condition de secteur modifiée permettant de prendre en compte la saturation de l'accélération et la description du système en boucle fermée via un modèle polytopique des incertitudes. Cette approche permet de formuler des conditions constructives pouvant être exprimées sous forme d'Inégalités Linéaires Matricielles (LMIs). Sur cette base, la résolution de problèmes d'optimisation convexe permet d'une part de maximiser la région de stabilité associée et d'autre part de déterminer le gain stabilisant du correcteur. La technique, initialement appliquée au problème du positionnement de la caméra par rapport à une cible fixe, est ensuite étendue au suivi d'une cible mobile en considérant la vitesse inconnue de la cible comme une perturbation bornée en énergie. L'intérêt de ce type de résultat, pour l'élaboration de stratégies de navigation d'un robot mobile pa r enchaînement de tâches référencées capteurs, est ensuite mis en évidence. Plusieurs exemples d'enchaînement de tâches sont tour à tour considérés et simulés sur la base d'un modèle de robot à roues muni de capteurs de proximité et supportant une caméra montée sur une platine orientable en azimut.
40
Tyrie, Elizabeth Katharyn. "Combining Quantitative Eye-Tracking and GIS Techniques with Qualitative Research Methods to Evaluate the Effectiveness of 2D and Static, 3D Karst Visualizations: Seeing Through the Complexities of Karst Environments." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1351.
Анотація:
Karst environments are interconnected landscapes vulnerable to degradation. Many instances of anthropogenic karst disturbance are unintentional, and occur because of the public's lack of understanding or exposure to karst knowledge. When attempts are made to educate the general public about these landscapes, the concepts taught are often too abstract to be fully understood. Thus, karst educational pursuits must use only the most efficient and effective learning materials. A technique useful for assessing educational effectiveness of learning materials is eye-tracking, which allows scientists to quantitatively measure an individual's points of interest and eye movements when viewing a 2D or 3D visualization. Visualization developers use eye-tracking data to create graphics that hold the observer's attention and, thereby, enhance learning about a particular concept. This study aimed to assess and improve the educational effectiveness of 2D karst visualizations by combining eye-tracking techniques with Geographic Information Systems, knowledge assessments, and semi-structured interviews. The first phase of this study consisted of groups of 10 participants viewing 2D karst visualizations with one category of manipulated visual stimuli. The second phase consisted of groups of 10-15 participants viewing 2D karst visualizations that were created based on the results from the first phase. The results of this study highlighted both effective stimuli in karst visualizations and stimuli that hinder the educational effectiveness of visualizations.
41
Zhang, Yuqi. "ROBOMIRROR: A SIMULATED MIRROR DISPLAY WITH A ROBOTIC CAMERA." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/55.
Анотація:
Simulated mirror displays have a promising prospect in applications, due to its capability for virtual visualization. In most existing mirror displays, cameras are placed on top of the displays and unable to capture the person in front of the display at the highest possible resolution. The lack of a direct frontal capture of the subject's face and the geometric error introduced by image warping techniques make realistic mirror image rendering a challenging problem. The objective of this thesis is to explore the use of a robotic camera in tracking the face of the subject in front of the display to obtain a high-quality image capture. Our system uses a Bislide system to control a camera for face capture, while using a separate color-depth camera for accurate face tracking. We construct an optical device in which a one-way mirror is used so that the robotic camera behind can capture the subject while the rendered images can be displayed by reflecting off the mirror from an overhead projector. A key challenge of the proposed system is the reduction of light due to the one-way mirror. The optimal 2D Wiener filter is selected to enhance the low contrast images captured by the camera.
42
Baldi, Andrea. "Valutazione della cardiotossicità in pazienti oncologici mediante tecniche ecocardiografiche." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11144/.
Анотація:
L'elaborato si inserisce in un progetto sviluppato presso l'Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (I.R.S.T.) di Meldola che riguarda la valutazione di parametri cardiologici che possano risultare indici predittivi di uno scompenso cardiaco in pazienti affetti da linfoma.
Tutti i soggetti considerati nel progetto sono stati sottoposti a trattamenti chemioterapici facenti uso di antracicline e la cui funzionalità cardiaca è stata controllata periodicamente tramite ecografia bidimensionale e volumetrica, utilizzando il sistema VividE9 della GE Healthcare.
L'obiettivo dell'analisi è quello di ricercare se oltre alla frazione di eiezione esistono parametri più predittivi di una eventuale cardiotossicità come gli strain, calcolati attraverso l'ausilio della tecnica ecografica.
43
Philouze, Clothilde. "Dépistage des altérations précoces de la fonction régionale myocardique par échocardiographie de stress et effet d’une intervention par supplémentation en vitamine D3 dans le diabète de type 2 : approche translationnelle." Thesis, Avignon, 2018. http://www.theses.fr/2018AVIG0346/document.
Анотація:
Le diabète est aujourd’hui la 7ème cause de mortalité dans le monde. Dans cette population, la cardiomyopathie diabétique est la principale cause de morbi-mortalité. Le développement de cette complication débutant dès l’apparition du diabète, un dépistage et une prise en charge précoces de cette pathologie sont donc de première importance et sont les deux objectifs visés par ces travaux. La première étude que nous avons réalisée a permis de démontrer l’utilité d’une évaluation compréhensive de la fonction régionale myocardique gauche par 2D speckle-tracking imaging, en conditions de stress à la dobutamine, dans le dépistage précoce de la cardiomyopathie diabétique chez des patients diabétiques de type 2 asymptomatiques. La deuxième partie de ces travaux a, quant à elle, donné lieu à deux études. L’étude clinique a permis de mettre en évidence une amélioration de la réponse au stress de la fonction régionale myocardique après 3 mois de supplémentation en vitamine D3 chez des patients carencés. L’étude expérimentale a, pour sa part, souligné les effets bénéfiques sur le remodelage et la fonction cardiaques de cette supplémentation, en prévention secondaire, dans un modèle murin de diabète de type 2 induit par un régime gras et sucré. Par ailleurs, cette étude a mis en lumière l’implication potentielle d’une modulation des taux myocardiques en espèces lipotoxiques par la vitamine D3 dans ces effets. L’ensemble de ces travaux de thèse a ainsi permis, d’une part, de proposer une technique de dépistage des signes précoces d’altération de la fonction cardiaque chez le patient diabétique de type 2 et, d’autre part, de montrer les effets bénéfiques d’une supplémentation en vitamine D3 dans ce contexteDiabetes has reached the 7th place in the world’s top ten mortality causes. In this population, morbi-mortality mainly originates from diabetic cardiomyopathy. This complication evolving from the onset of diabetes, early diagnosis and care are of paramount importance and are the two purposes of this work. In our first study, we demonstrated the relevance of a comprehensive 2D speckle-tracking imaging analysis, under dobutamine stress, in unmasking early left ventricular regional myocardial dysfunction in a population of asymptomatic type 2 diabetic patients. In the second part of this work, we performed two studies. In the first one, we brought to light an improvement of regional myocardial function response to dobutamine stress after a three-month vitamin D3 supplementation protocol, in deficient patients. The second study was performed in a mouse model of diet-induced type 2 diabetes. In this last work, we put forward the beneficial effects of vitamin D3 supplementation, in secondary prevention, on cardiac remodeling and function. These cardioprotective effects may be, at least in part, on account of modulatory effects of vitamin D3 on myocardial lipotoxic species levels. This whole work allow us to propose a tool enabling recognition of early cardiac function impairments in type 2 diabetic patients and to demonstrate the beneficial effects of vitamin D3 supplementation in this context
44
Salmane, Houssam. "Reconstruction et analyse de trajectoires 2D d'objets mobiles par modélisation Markovienne et la théorie de l'évidence à partir de séquences d'images monoculaires - Application à l'évaluation de situations potentiellement dangereuses aux passages à niveau." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2013. http://tel.archives-ouvertes.fr/tel-00965595.
Анотація:
Les travaux présentés dans ce mémoire s'inscrivent dans le cadre duprojet PANsafer (Vers un Passage A Niveau plus sûr), lauréat de l'appel ANR-VTT2008. Ce projet est labellisé par les deux pôles de compétitivité i-Trans et Véhiculedu Futur. Le travail de la thèse est mené conjointement par le laboratoire IRTESSETde l'UTBM et le laboratoire LEOST de l'IFSTTAR.L'objectif de cette thèse est de développer un système de perception permettantl'interprétation de scénarios dans l'environnement d'un passage à niveau. Il s'agitd'évaluer des situations potentiellement dangereuses par l'analyse spatio-temporelledes objets présents autour du passage à niveau.Pour atteindre cet objectif, le travail est décomposé en trois étapes principales. Lapremière étape est consacrée à la mise en place d'une architecture spatiale des capteursvidéo permettant de couvrir de manière optimale l'environnement du passageà niveau. Cette étape est mise en oeuvre dans le cadre du développement d'unsimulateur d'aide à la sécurité aux passages à niveau en utilisant un système deperception multi-vues. Dans ce cadre, nous avons proposé une méthode d'optimisationpermettant de déterminer automatiquement la position et l'orientation descaméras par rapport à l'environnement à percevoir.La deuxième étape consisteà développer une méthode robuste de suivi d'objets enmouvement à partir d'une séquence d'images. Dans un premier temps, nous avonsproposé une technique permettant la détection et la séparation des objets. Le processusde suivi est ensuite mis en oeuvre par le calcul et la rectification du flotoptique grâce respectivement à un modèle gaussien et un modèle de filtre de Kalman.La dernière étape est destinée à l'analyse des trajectoires 2D reconstruites parl'étape précédente pour l'interprétation de scénarios. Cette analyse commence parune modélisation markovienne des trajectoires 2D. Un système de décision à basede théorie de l'évidence est ensuite proposé pour l'évaluation de scénarios, aprèsavoir modélisé les sources de danger.L'approche proposée a été testée et évaluée avec des données issues de campagnesexpérimentales effectuées sur site réel d'un passage à niveau mis à disposition parRFF.
45
Draréni, Jamil. "Exploitation de contraintes photométriques et géométriques en vision : application au suivi, au calibrage et à la reconstruction." Grenoble, 2010. http://www.theses.fr/2010GRENM061.
Анотація:
Cette thèse s'intéresse à trois problèmes fondamentaux de la vision par ordinateur qui sont le suivi vidéo, le calibrage et la reconstruction 3D. Les approches proposées sont strictement basées sur des contraintes photométriques et géométriques présentent dans des images 2D. Le suivi de mouvement se fait généralement dans un flux vidéo et consiste à suivre un objet d'intérêt identifié par l'usager. Nous reprenons une des méthodes les plus robustes à cet effet et l'améliorons de sorte à prendre en charge, en plus de ses translations, les rotations qu'effectue l'objet d'intérêt. Par la suite nous nous attelons au calibrage de caméras ; un autre problème fondamental en vision. Il s'agit là, d'estimer des paramètres intrinsèques qui décrivent la projection d'entités 3D dans une image plane. Plus précisément, nous proposons des algorithmes de calibrage plan pour les caméras linéaires (pushbroom) et les vidéo projecteurs lesquels étaient, jusque-là, calibrés de façon laborieuse. Le troisième volet de cette thèse sera consacré à la reconstruction 3D par ombres projetée. À moins de connaissance à priori sur le contenu de la scène, cette technique est intrinsèquement ambigüe. Nous proposons une méthode pour réduire cette ambiguïté en exploitant le fait que les spots de lumières sont souvent visibles dans la caméraThe topic of this thesis revolves around three fundamental problems in computer vision; namely, video tracking, camera calibration and shape recovery. The proposed methods are solely based on photometric and geometric constraints found in the images. Video tracking, usually performed on a video sequence, consists in tracking a region of interest, selected manually by an operator. We extend a successful tracking method by adding the ability to estimate the orientation of the tracked object. Furthermore, we consider another fundamental problem in computer vision: calibration. Here we tackle the problem of calibrating linear cameras (a. K. A: pushbroom)and video projectors. For the former one we propose a convenient plane-based calibration algorithm and for the latter, a calibration algorithm that does not require aphysical grid and a planar auto-calibration algorithm. Finally, we pointed our third research direction toward shape reconstruction using coplanar shadows. This technique is known to suffer from a bas-relief ambiguity if no extra information on the scene or light source is provided. We propose a simple method to reduce this ambiguity from four to a single parameter. We achieve this by taking into account the visibility of the light spots in the camera
46
Ericsson, Duffy Mikael. "DRAWN TO LIFE: Exploring real-time manipulation of the digitally represented surface in comics on smartphones and tablets." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-23439.
Анотація:
This research thesis is an exploration into what possibilities lie beyond the representation of analog material when it transcends into the digital realm. Specifically, how printed comics can be altered in realtime by creator- allowed user interaction, when adapted for presentation within the digital sphere of mobile smartphones and computer tablets. Using legacy computer-game techniques like parallax scrolling with modern digital layer filters, device sensors and applying them in realtime to the comic creators digitally layered content, alternative forms of presentation arise.This is an investigation into the comic creator’s will of allowing possibilities of added depth perception, interactivity and alternative visual narratives in their comic, manga or graphic novels when employing new techniques based on sensor data input from a reader, like accelerometer-, gyroscope- or eye-tracking sensors. Several different techniques are evaluated. The focus is mainly on the context of creators of comics or manga who use digital tools and layer compositions when producing their work. Several aspects of the user-centered experience are also explored.Although mainly an interaction design project, most of the design methods are used from a service design approach, emphasizing co-design techniques like interviews, observations and user tests. The results are digital prototypes and proof-of-concepts featuring technology tests that support final design conclusions.The results will show both enthusiasm and reluctance from test subjects towards the new technologies presented. The professional craft of comic, manga and graphic novel creation has a deeply rooted aesthetic and production cycle in its history of the printed form. It could be difficult to alter its standard, reverence and nostalgia in the eyes of its readers and creators, when pursuing the digital format and narrative possibilities of the future. A video explaining the project’s “Drawn To Life” technology is available online.
47
Huang, Ya-Chi, and 黃雅琦. "3D Hand Posture Tracking Using 2D Camera Images." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/81908081738827390417.
Анотація:
碩士國立交通大學
資訊科學與工程研究所
103
In this thesis, we present the design of a 3D model-based hand posture tracking system using a single sequence of 2D camera images. The system is composed of several stages. During the pre-processing stage, we retrieve the hand area from the 2D camera image by employing the OpenCV functions of image rectification and codebook training for foreground/background separation. The 3D hand model is constructed using Blender, which is a 3D graphics authoring tool. The hand model is then converted to the OGRE format so that we can use the OGER rendering engine to control the movement of the 3D hand model. During the hand posture tracking stage, we implemented several exiting methods proposed by other researchers. The extraction of fingertips and palm positions are achieved simply by using the contours of the 2D image. We also implemented the Point Distribution Model (PDM) method, this method needs a set of hand posture training data, and calculating the mean shape and eigenvectors by applying Principle Component Analysis (PCA). We then refined the PDM method by changing the training data of PCA from the position of landmarks to the rotation angles of joints. In this way, the movement of the animated hand conforms to the kinematic model of a real hand. Eventually, this thesis proposed a framework that tracks the hand posture by brute-force matching between all the possible postures of the 3D hand model and the observed 2D hand contours to determine the most likely 3D hand posture.
48
Huang, Rui-yi, and 黃瑞逸. "Tracking Control of A Vision Based 2D Pneumatic Arm." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/28472525841934930245.
Анотація:
碩士國立臺灣科技大學
機械工程系
100
This thesis is mainly to combine 2D pneumatic arm and a CCD, which is stored in the edge of the arm. This system is applied for tracking control of the object. The arm is setup by pneumatic muscles. It can capture the 2D location of an object via the image processing and coordinate transformation. Then, the self-organizing sliding mode fuzzy controller is designed for the encoder feedback control and drive the pneumatic arm to perform trajectory tracking. From experiments, it tests and verifies the self-organizing sliding mode fuzzy controller for the vision based 2D pneumatic arm, through point-to-point and various speed tracking experiments, in order to evaluate the control performance.
49
Prouza, Ondřej. "2D stíhací tracking task, zhodnocení za stabilních experimentálních podmínek." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-287463.
Анотація:
Souhrn: Název práce: 2D stíhací tracking task, zhodnocení za stabilních experimentálních podmínek. Title ofwork: 2D pursuit tracking task method, assesment under stable experimental conditions. Cíle práce: Rešeršní shrnutí problematiky tracking task v literatuře. Parametrizace vhodné tracking task úlohy ajejí experimentální zhodnocení na skupině dobrovolm'ků. Metoda: 2D stíhací tracking task, prvního řádu s využitím joysticku jako vstupního zařízení. Statistické zhodnocení v programu Matlab 2006 - statistická analýza, Fourierova transformace. Výsledky: Výkon v závislosti na čase nevykazuje v použitém testu jednoznačné souborné charaktistiky, střední kvadratická chyba jedinců z vymezeného populačního vzorku se pohybuje v úzkém intervalu. Klíčová slova: tracking task, parametrizace, psychomotorický výkon
50
Trache, Marian Tudor. "The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate: The agreement between 3D, standard 2D and triplane 2Dspeckle tracking: effects of image quality and 3D volumerate." Doctoral thesis, 2015. https://ul.qucosa.de/id/qucosa%3A14692.
Анотація:
Die technologische Entwicklung im Bereich der Echokardiographie hat in der
letzten Dekade neue Methoden zur objektiven Erfassung der regionalen linksventrikulären
Wandbewegung ermöglicht. Speckle Tracking erfasst die myokardiale Deformation durch
die Positionsänderung einzelner Bildpunkte von einem Bild des analysierten Datensatzes
zum nächsten. Diese Methode ist dem Gewebedoppler überlegen, insbesondere wegen ihrer
Unabhängigkeit vom Anlotungswinkel. Zwei-dimensionale (2D) Speckle Tracking
Analysen wurden für die klinische Praxis validiert. Die drei-dimensionale (3D)
Echokardiographie erlaubt inzwischen Speckle Tracking Analysen von 3D Datensätzen,
welche jedoch für die klinische Praxis noch nicht ausreichend validiert sind.
Bei Patienten mit normaler regionaler linksventrikulärer Wandbewegung (N=37), sowie bei
Patienten mit ischämie-bedingten Wandbewegungsstörungen (N=18) wurden 3D und 2D
Speckle Tracking Analysen durchgeführt. Die Vergleichbarkeit der beiden Methoden
hinschtlich der Quantifizierung von normalen und pathologischen Wandbewegungsmustern
wurde anhand dieser Messungen geprüft. Des weiteren wurde der Einfluss der Bildrate und
Bildqualität drei-dimensionaler Datensätze auf die Vergleichbarkeit beider Methoden
analysiert.
Es zeigte sich eine gute Vergleichbarkeit des 2D und 3D Speckle Tracking in der
Diagnostik eingeschränkter linksventrikulärer systolischer Funktion, sowie in der
Lokalisationsdiagnostik umschriebener Wandbewegungsstörungen. 2D und 3D Speckle
Tracking sind jedoch noch nicht als gleichwertige Methoden anzusehen. Die Bildqualität,
generell bei beiden Modalitäten - jedoch speziell bei 3D Datensätzen, sowie die Bildrate
der 3D Datensätze zeigen signifikante Einflüsse auf die 3D Strain Analysen. Eine korrekte
Standardisierung der analysierten Aufnahmen und eine optimale Bildqualität sind wichtige
Faktoren, die die Zuverlässigkeit des 2D und 3D Speckle Trackings bestimmen.