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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Evaluation of computerised programs for the diagnosis and treatment of binocular anomalies

Lin, Wei January 2016 (has links)
Computerised diagnostic testing and computerised vision training (VT) have been developed for the orthoptic management of binocular vision (BV) anomalies in clinical practice. Computerised measurement of BV is assumed to assist accurate diagnosis of BV anomalies because variability of testing resulting from subjective judgements of examiners is eliminated by automatic measurements. Computerised VT is thought to be effective in the treatment of BV anomalies because the computer games used for vision training will enhance the patient's motivation. However, these assumptions were lacking scientific support. This thesis reports a range of studies to investigate the computerised programs of diagnostic testing (HTS-BVA) and vision training (HTS-iNet) in comparison with corresponding traditional approaches, respectively. The first study was to investigate inter-session repeatability of computerised testing on BV functions. The study results showed that computerised testing on measuring near horizontal fusional vergence (FV) and accommodative facility (AF) did not present higher inter-session repeatability than corresponding traditional testing. The second study was a pilot study for a future rigorous randomized clinical trial (RCT) investigating effectiveness of computerised VT as a home-based treatment for convergence insufficiency (CI). The study results showed the subjects with CI demonstrated improvement of near point of convergence (NPC), near base-out FV and symptoms associated with CI after an 8-week treatment regime. The third study, following from the first study, was to investigate whether accommodative responses (AR) are affected by the novel accommodative stimuli used in computerised AF testing. The study results showed the AR might be affected by the colours of accommodative targets and the colour filter used. Especially, the data of accommodative demand of 4 dioptres revealed that blue targets presented poorer AR than red targets, and the targets seen with colour filters presented poorer AR than those seen without colour filters. The fourth study, also following from the first study, was to investigate whether a prolonged near vision task affects measurements made relating to the near FV system, thus contributing to the variability of clinical findings. The study results showed statistically significant changes in NPC and near dissociated phoria. In further sub-group analyses, the subjects with an initially poor NPC (n = 9) presented greater changes in the NPC and near dissociated phoria than the subjects with normal poor NPC (n = 25).Overall, the computerised testing did not show more repeatable BV measurements than the traditional testing. Finally, an RCT is needed to determine if the computerised VT is more effective than placebo computerised VT as a home-based treatment for CI.
162

Descripteurs 2D et 2D+t de points d'intérêt pour des appariements robustes / 2D and 2D+t descriptors of points of interest for robust matching

Grand-Brochier, Manuel 18 November 2011 (has links)
De nos jours les méthodes de vision par ordinateur sont utilisées dans de nombreuses applications telles que la vidéo-surveillance, l'aide à la conduite ou la reconstruction 3D par exemple. Ces différentes applications s'appuient généralement sur des procédés de reconnaissance de formes ou de suivi. Pour ce faire, l'image est analysée afin d'en extraire des amers ou des primitives (contours, fonctions d'intensité ou modèles morphologiques). Les méthodes les plus courantes s'appuient sur l'utilisation de points d'intérêt représentant une discontinuité des niveaux de gris caractérisant un coin dans une image. Afin de mettre en correspondance un ensemble de points d'une image à une autre, une description locale est utilisée. Elle permet d'extraire l'information du voisinage de chaque point (valeurs des pixels, des intensités lumineuses, des gradients). Dans le cas d'applications telles que la vidéo-surveillance ou les caméras embarquées, l'ajout d'une information temporelle est fortement recommandé. Cette généralisation est utilisée au sein du laboratoire pour des projets de type véhicules intelligents (CyCab : véhicule intelligent, VELAC : VEhicule du Lasmea pour l'Aide à la Conduite). Les travaux de recherche présentés dans ce mémoire ont pour objectif de mettre en oeuvre différents outils de détection, description et mise en correspondance de points d'intérêt. Un certain nombre de contraintes a été établi, notamment l'utilisation d'images en niveaux de gris, la robustesse et l'aspect générique de la méthode. Dans un premier temps, nous proposons une analyse bibliographique des méthodes existantes. Cette dernière permet en effet d'en déduire les paramètres de mise en oeuvre ainsi que les principaux avantages et inconvénients. Nous détaillons par la suite la méthode proposée. La détection des primitives repose sur l'utilisation du détecteur fast-hessien que nous optimisons. L'utilisation d'une description locale basée sur des histogrammes de gradients orientés (HOG) est très répandue et procure de très bons résultats. Nous proposons de compléter son utilisation par un recalage et une mise à l'échelle d'un masque d'analyse elliptique créant ainsi une nouvelle forme de description locale (E-HOG). La mise en correspondance des points d'intérêt se base quant à elle sur une approche par corrélation à laquelle nous ajoutons un coefficient de sélection ainsi qu'une étape de suppression des doublons. Les différents résultats validant notre approche s'appuient sur l'utilisation de transformations synthétiques (vérité terrain) ou réelles. Nous proposons également une généralisation de notre approche au domaine spatiotemporel, permettant ainsi d'élargir son domaine d'utilisation. Le masque d'analyse précédemment cité est modifié et s'appuie donc sur l'utilisation d'ellipsoïdes. Les tests de validation reposent d'une part sur des séquences vidéo ayant subi des transformations synthétiques et d'autre part sur des séquences réelles issues de la plate-forme PAVIN (Plate-forme d'Auvergne pour Véhicules Intelligents). / Pas de résumé disponible
163

The effect of tinted lenses on colour discrimination and contrast sensitivity

Ramkissoon, Prithipaul 27 October 2008 (has links)
M. Phil. / Please refer to full text to view abstract / Prof. J.T. Ferreira
164

The development of norms and protocols in sports vision evaluations

Buys, Hendri 27 October 2008 (has links)
M.Phil. / Sports vision has been a part of sport for a long time, probably since an athlete was first told to: ‘keep his eye on the ball’. It is only recently that athletes are beginning to realize the advantages of using their eyes to their full potential, and the difference it can make in an athlete’s performance. This is more prevalent today, where athletes can become instant hero’s and earn huge salaries. For a number of years specific instruments were used to test specific visual skills and norms were calculated for these skills. A few questions arises though when the norms for these visual skills are carefully studied. The purpose of this study was to evaluate previous norms and to develop norms and protocols for sports vision evaluations. Various visual skills were examined and previously used results evaluated. Key performance indicators in the evaluation of an athletes, as well as the cornerstones of sport vision were also discussed. Only elite athletes were used in this study. / Prof. J.T. Ferreira
165

Intelligent Stereo Video Monitoring System for Paramedic Helmet

Liu, Yang January 2017 (has links)
During the first aid process, when patients are threatened by poor medical conditions, ambulance paramedics are required to administer emergency treatment based on instruc- tions provided by a remote emergency doctor through voice communication. However, such voice communication is always limited in expressing abundant detailed information for the patient. This thesis presents a framework for a stereoscopic and intelligent telemedicine sys- tem that can provide 3D live video communication between paramedics and emergency doctors. The proposed system captures 3D video from the paramedic headset carried by the paramedics, transmits the video through wireless live streaming, and displays the video with a 3D effect for emergency doctors in the hospital. The video can be analyzed to extract information about the patient through embedded algorithm such as face de- tection algorithm. In this thesis, the hardware, functional mechanism and face detection algorithm are introduced separately. The hardware of the system consists of a paramedic headset, a server box and a 3D PC, which are used to capture 3D video, transmit video through live streaming and display video with a stereo effect, respectively. The functional mechanism includes two subsystems, which work for pushing the stereo video to multiple live streams and displaying the 3D video from the live stream. In order to detect the patient information from the video, a multi-task face detection algorithm is applied to analyze the stereo video using deep learning technology. We improved the neural networks of face detection by utilizing 1 ⇥ 1 convolutional layers and retrain the network based on the transfer learning to achieve better and faster performance. This system has achieved good and stable performance in network delay (0.0489ms) and objective video quality evaluations. The face detection algorithm has achieved no- table accuracy (91.78% In FDDB dataset) and efficiency (19.71 ms/frame).
166

Aplikace stereovize a počítačového vidění / Computer vision and stereo vision

Bubák, Martin January 2014 (has links)
This dissertation work is describing the usage of the software tool Computer Vision System Toolbox to create applications in computer vision. At the beginning of the work is performed background research of image scanning and its representation by using colour models. It is followed by a description of epipolar geometry and lastly is stated a description of the Computer Vision System Toolbox. In the next section of the work we deal with setting of used Basler cameras and processing of the scanned image. The following is a description how to create applications for object detection and after this description, we get to know applications for creation of depth maps area.
167

An automated vision system using a fast 2-dimensional moment invariants algorithm /

Zakaria, Marwan F. January 1987 (has links)
No description available.
168

Human S-cone electroretinograms obtained by silent substitution stimulation

Maguire, John, Parry, Neil R.A., Kremers, Jan, Murray, I.J., McKeefry, Declan J. 2017 December 1927 (has links)
Yes / We used triple silent substitution stimuli to characterize human S-cone electroretinograms (ERGs) in normal trichromats. Short-wavelength-cone (S-cone) ERGs were found to have different morphological features and temporal frequency response characteristics compared to ERGs derived from L-cones, M-cones, and rod photoreceptors in normal participants. Furthermore, in two cases of retinal pathology, blue cone monochromatism (BCM) and enhanced S-cone syndrome (ESCS), S-cone ERGs elicited by our stimuli were preserved and enhanced, respectively. The results from both normal and pathological retinae demonstrate that triple silent substitution stimuli can be used to generate ERGs that provide an assay of human S-cone function. / Deutsche Forschungsgemeinschaft (DFG) (KR1317/13-1); Bundesministerium für Bildung und Forschung (BMBF) (01DN14009)
169

Evidence for chromatic edge detectors in human vision using classification images

McIlhagga, William H., Mullen, K.T. 07 September 2018 (has links)
Yes / Edge detection plays an important role in human vision, and although it is clear that there are luminance edge detectors, it is not known whether there are chromatic edge detectors as well.We showed observers a horizontal edge blurred by a Gaussian filter (with widths of r ¼ 0.1125, 0.225, or 0.458) embedded in blurred Brown noise. Observers had to choose which of two stimuli contained the edge. Brown noise was used in preference to white noise to reveal localized edge detectors. Edges and noise were defined by either luminance or chromatic contrast (isoluminant L/M and S-cone opponent). Classification image analysis was applied to observer responses. In this analysis, the random components of the stimulus are correlated with observer responses to reveal a template that shows how observers weighted different parts of the stimulus to arrive at their decision.We found classification images for both luminance and isoluminant chromatic stimuli that had shapes very similar to derivatives of Gaussian filters. The widths of these classification images tracked the widths of the edges, but the chromatic edge classification images were wider than the luminance ones. These results are consistent with edge detection filters sensitive to luminance contrast and isoluminant chromatic contrast. / Royal Society Travel Grant IE130877 and in part by Canadian Institutes of Health Research (CIHR) grant MOP-10819
170

Black and white referencing paths and the retinex theory of color vision.

Stork, David Geoffrey. January 1976 (has links)
Thesis: B.S., Massachusetts Institute of Technology, Department of Physics, 1976 / Bibliography: leaves [73-74]. / B.S. / B.S. Massachusetts Institute of Technology, Department of Physics

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