Η ραγδαία αύξηση των εικόνων, σε συνδυασμό με την αδυναμία των συστημάτων ανάκτησης εικόνας βάσει περιεχομένου να εξάγουν σημασιολογικά χαρακτηριστικά, οδήγησαν στην εισαγωγή του ανθρώπινου παράγοντα στην πειραματική διαδικασία. Ένας πολύ συνηθισμένος και επιτυχημένος τρόπος χρησιμοποίησης του ανθρώπινου συστήματος όρασης είναι μέσω της καταγραφής των οφθαλμικών κινήσεων. Στο σύστημα ανάκτησης το οποίο προτείνεται στην παρούσα εργασία γίνεται καταγραφή των σημείων εστίασης που προέκυψαν κατά την παρατήρηση των εικόνων βάσεως. Από τα σημεία αυτά, γίνεται εξαγωγή χαρακτηριστικών υφής με δύο μεθόδους, τα φίλτρα Gabor και το διακριτό μετασχηματισμό συνημιτόνου (DCT), παράγοντας πολυδιάστατα διανύσματα. Τα διανύσματα αυτά συγκρίνονται ανά δύο μέσω του μη παραμετρικού WW test, δημιουργώντας έναν πίνακα αποστάσεων. Με την εισαγωγή μιας ζητούμενης εικόνας στο σύστημα, τα χαρακτηριστικά υφής της συγκρίνονται με αυτά της βάσης προσθέτοντας μια επιπλέον διάσταση στον πίνακα απόστασης. Η απεικόνιση της σχέσης μεταξύ όλων των εικόνων (συμπεριλαμβανομένης και της αιτούμενης) γίνεται σε ένα χάρτη τριών διαστάσεων μέσω πολυδιάστατης κλιμάκωσης (MDS αλγόριθμος). Τα αποτελέσματα τα οποία προέρχονται από τα φίλτρα Gabor παρουσιάζουν μεγαλύτερη αξιοπιστία, κάνοντας εφικτή την επέκταση του συστήματος με χρήση μίας μεγαλύτερης βάσης εικόνων. / The rapid increase of images, combined with the weakness of the Content Based Image Retrieval (CBIR) systems to extract semantic features, led to the introduction of the human factor into the experimental procedure. A very common and successful way of using the human vision system is through the record of eye movements. In the retrieval system which is proposed in the present thesis, the fixation points that arose from viewing the database images are recorded. From these points, the texture features are extracted using two methods, Gabor filters and Discrete Cosine Transform (DCT), producing multidimensional vectors. These vectors are compared through the non parametric WW test, creating a distance matrix. By producing a query image in the system, its’ texture features are compared to those of the database, adding an extra dimension to the distance matrix. The visual representation of the relation among all the images (query image included), is depicted in a three dimensional map using multidimensional scaling (MDS algorithm). The results obtained from Gabor filters are characterized by higher robustness, making the expansion of the system possible, by using a bigger image database.

Thesis (MEng)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The next generation of CubeSats will require accurate attitude knowledge throughout orbit for advanced science payloads and high gain antennas. A star tracker can provide the required performance, but star trackers have traditionally been too large, expensive and power hungry to be included on a CubeSat. The aim of this project is to develop and demonstrate a CubeSat compatible star tracker. Subsystems from two other CubeSat components, CubeSense and CubeComputer, were combined with a sensitive, commercial image sensor and low-light lens to produce one of the smallest star trackers in existence. Algorithms for star detection, matching and attitude determination were investigated and implemented on the embedded system. The resultant star tracker, named CubeStar, can operate fully autonomously, outputting attitude estimates at a rate of 1 Hz. An engineering model was completed and demonstrated an accuracy of better than 0.01 degrees during night sky tests. / AFRIKAANSE OPSOMMING: Die volgende generasie van CubeSats sal akkurate orientasie kennis vereis gedurende 'n volle omwentelling van die aarde. 'n Sterkamera kan die vereiste prestasie verskaf, maar sterkameras is tradisioneel te groot, duur en krag intensief om ingesluit te word aanboord 'n CubeSat. Die doel van hierdie projek is om 'n CubeSat sterkamera te ontwikkel en te demonstreer. Substelsels van twee ander CubeSat komponente, CubeSense en CubeComputer, was gekombineer met 'n sensitiewe kommersiële beeldsensor en 'n lae-lig lens om een van die kleinste sterkameras op die mark te produseer. Algoritmes vir die ster opsporing, identi kasie en orientasie bepaling is ondersoek en geïmplementeer op die ingebedde stelsel. Die gevolglike sterkamera, genaamd CubeStar, kan ten volle outonoom orientasie afskattings lewer teen 'n tempo van 1 Hz. 'n Ingenieursmodel is voltooi en 'n akkuraatheid van beter as 0.01 grade is gedemonstreer.

Orientador: Michael John Brennan / Resumo: Nesta tese são investigadas, teórica e experimentalmente, a sincronização em fase e a sincronização em anti-fase de dois metrônomos oscilando sobre uma base móvel, a partir de um modelo aqui proposto. Uma descrição do funcionamento do mecanismo de escapamento dos metrônomos é feita, junto a um estudo da relação entre este e o oscilador de van der Pol. Também uma aproximação experimental do valor do amortecimento do metrônomo é fornecida. A frequência instantânea das respostas, numérica e experimental, do sistema é usada na analise. A diferença de outros trabalhos prévios, os dados experimentais têm sido adquiridos usando vídeos dos experimentos e extraídos com ajuda do software Tracker. Para investigar a relação entre as condições iniciais do sistema e seu estado final de sincronização, foram usados mapas bidimensionais chamados ‘basins of attraction’. A relação entre o modelo proposto e um modelo prévio também é mostrada. Encontrou-se que os parâmetros relevantes em relação a ambos os tipos de sincronização são a razão entre a massa do metrônomo e a massa da base, e o amortecimento do sistema. Tem-se encontrado, tanto experimental quanto teoricamente, que a frequência de oscilação dos metrônomos aumenta quando o sistema sincroniza-se em fase, e se mantém a mesma de um metrônomo isolado quando o sistema sincroniza-se em anti-fase. A partir de simulações numéricas encontrou-se que, em geral, incrementos no amortecimento do sistema levam ao sistema se sincronizar mais em fase d... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Made available in DSpace on 2015-03-26T13:23:47Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2831584 bytes, checksum: 6baba1e231f02f91abcbd5fea6a40dd2 (MD5) Previous issue date: 2011-07-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the results of the study related to the production of electricity using a photovoltaic panel attached to the solar tracking mechanism. The objective was to develop a tracker equipment effective, with low cost and energy consumption, targeting the residential use, industrial and distributed generation of energy. Was evaluated the performance of the tracker, comparing it to a fixed system, showing its greatest potential for conversion. Based on the results analyzed, was observed a significant increase in energy conversion panel coupled to the tracking system in relation to fixed panel in a tilt angle accordingly local latitude. Its electromechanical performance was satisfactory, with no need for maintenance during the trial period and exposed to various weather conditions. The system has shown great potential for application usability and robustness / Neste trabalho estão apresentados os resultados do estudo relacionado à produção de eletricidade utilizando um painel fotovoltaico acoplado ao mecanismo de rastreamento solar. Objetivou-se desenvolver um equipamento eficaz no rastreamento, de baixo custo e consumo de energia, visando à possibilidade de uso residencial, industrial e a geração distribuída de energia. Avaliou-se o desempenho do rastreador, comparando-o com um sistema fixo. Com base nos resultados analisados, observou-se aumento significativo na produção de energia do painel fotovoltaico acoplado ao sistema de rastreamento em relação ao sistema fixo à inclinação da latitude local. Seu desempenho eletromecânico foi satisfatório, não necessitando de manutenção durante a fase experimental mesmo quando exposto às mais variadas condições de tempo. O sistema demonstrou grande potencial de aplicação, usabilidade e robustez.

Made available in DSpace on 2014-12-17T14:56:16Z (GMT). No. of bitstreams: 1 JoseRVL_DISSERT.pdf: 1074051 bytes, checksum: 14c63dffcde0a8f8267956ed973bedb7 (MD5) Previous issue date: 2014-01-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of solar energy for electricity generation has shown a growing interest in recent years. Generally, the conversion of solar energy into electricity is made by PV modules installed on fixed structures, with slope determined by the latitude of the installation site. In this sense, the use of mobile structures with solar tracking, has enabled increased production of the generated energy. However, the performance of these structures depends on the type of tracker and the position control used. In this work, it is proposed position control a strategy applied for a solar tracker, which will be installed in Laboratory of Power Electronics and Renewable Energy (LEPER), located in the Federal University of Rio Grande do Norte (UFRN). The tracker system is of polar type with daily positioning east-west and tilt angle manual adjustment in the seasonal periods, from north to south / O aproveitamento da energia solar para gera??o de energia el?trica tem apresentado um crescente interesse nos ?ltimos anos. Geralmente nestes sistemas, a convers?o de energia solar em el?trica ? realizada por m?dulos fotovoltaicos, instalados em estruturas fixas, com inclina??o determinada em fun??o da latitude do local de instala??o. Neste sentido, o uso de estruturas m?veis, com rastreamento solar, tem possibilitado o incremento da produ??o da energia gerada. Por?m, o desempenho dessas estruturas depende do tipo de rastreador instalado e do tipo de controle de posi??o utilizado. Nesta disserta??o, ? empregada uma estrat?gia de controle de posi??o aplicada a um rastreador solar, que ser? instalado no Laborat?rio de Eletr?nica de Pot?ncia e Energias Renov?veis (LEPER), localizado na Universidade Federal do Rio Grande do Norte (UFRN). O rastreador ser? do tipo polar, com rastreamento di?rio no sentido leste-oeste e ajuste do ?ngulo de inclina??o manual nos per?odos sazonais, no sentido norte-sul

A matriz energética brasileira atualmente está concentrada na geração de energia hidrelétrica. Mas, devido aos últimos acontecimentos de escassez de recursos hídricos, faz-se necessário diversificar a matriz energética por meio do investimento em energias alternativas. O Brasil ainda possui muitas pessoas na área rural sem abastecimento de energia elétrica, fato que limita a implantação de técnicas agrícolas como a irrigação. Nesse contexto, a energia solar fotovoltaica (FV) é uma alternativa para diversificar a matriz energética brasileira e ampliar o uso de sistemas de irrigação. Foram instalados dois módulos FV, um estático e outro com um sistema de rastreamento solar manual de três passos, na área experimental do Departamento de Engenharia de Biossistemas - ESALQ/USP (22° 42\' 30\'\'S, 47° 38\' 00\'\'W, altitude de 546 metros). Para cada módulo FV, estático e móvel, foram acoplados sistemas de bombeamento de água para um sistema simulado de irrigação. O objetivo foi avaliar o incremento de energia FV gerada, tempo de bombeamento, volume bombeado e área irrigada; com o uso do sistema rastreador. A partir dos dados encontrados, verificou-se que o sistema rastreador solar manual de três passos apresentou maior eficiência na captação de energia (8 - 19% dia-1), quando comparado com geradores fixos; o que refletiu no incremento significativo do tempo de bombeamento (40 - 160 min dia-1), no volume bombeado (884 - 3479 litros dia-1) e na área irrigada (196 - 773 m² dia-1 para uma lâmina de irrigação de 4,5 mm). Com isso, o rastreador se mostrou uma alternativa técnica viável para melhorar a captação de energia solar e aumentar a área irrigada com um mesmo tamanho de área de gerador FV. Em relação ao investimento, o sistema rastreador custou apenas 0,2% do custo total da instalação FV, e proporcionou a redução do tempo de retorno do investimento em 2 anos e 5 meses comparado ao módulo FV estático. / The current Brazilian Energetic Matrix is concentrated in the generation of hydroelectric energy. But, due the latest water resources scarcity, it is necessary to diversify the energetic matrix by investing in alternatives energies. Brazil still have a plenty of people living in rural areas without supply of electric energy, this fact limits the implantation of agriculture techniques like irrigation. In this sense, the photovoltaic solar energy (PV) is an alternative to diversify the Brazilian Energetic Matrix and expand the use of irrigation systems. It were installed two PV modules, one static and another with solar three steps manual tracking system, Biosystems Engineering Department - ESALQ/USP (22° 42\' 30\'\'S, 47°38\' 00\'\'W, at 546 meters altitude). For each PV module, static and moving, it was coupled water pumping systems for simulated irrigation systems. The goal was evaluate the gain of the PV energy generated; pumping time; pumping volume and irrigated area; using the tracking system. From obtained data, it was observed that the solar three steps manual tracking system shows more efficiency in the energy harvesting (8 - 19% day-1), compared to static generator; which resulted in significant gain of pumping time (40 - 160 min day-1), pumping volume (884 - 3479 liters day-1) and irrigates area (196 - 773 m² day-1 for a irrigation depth equal 4.5 mm). Therewith, the tracking system shows a viable alternative technique to improve solar energy harvesting and increase the irrigated area with same area of PV generator. In relation to investment of the tracking system, it cost only 0.2 % of the total cost of PV installation and provided the reduction in the return on investment time of 2 years and 5 month compared to static PV module.

This thesis was performed at the research centre CINECA in Bologna, Italy. An interface with six degrees of freedom, 6DOF, to be used in a virtual environ- ment for the positioning of medical components was developed in co-operation with IOR, one of the most important orthopaedic hospitals in Italy. The main reason for doing this was to find out whether or not a virtual en-viron-ment and 6DOF interaction could make the pre-operative planning of an ope-ration more efficient compared to other techniques. Is it easy to posi-tion an object using stereovision and a 6DOF tracker tool? Further-more, the interface might also be used in other applications and areas in the future. Described is the development of an interaction class especially constructed for the use of a tracking tool called a stylus pen. This tool takes advantage of all 6DOF, i.e. it recognises movements in the x, y and z directions and likewise the orientation of the tool around the three axis. Moreover, an application which uses the interaction class was created in order to evaluate its usefulness. The application enables the user to load, save and position objects within a virtual environment. The result of this evaluation is then described and discussed. In the evaluations it was shown that the stylus pen with 6DOF is an intuitive in-ter-action tool which works well for positioning. The stereovision also seems to further improve the users ability to position objects. However, the created interaction class needs to be further developed before itcan be implemented in a pre-operative planning tool.

A face tracker is exactly what it sounds like. It tracks a face in a video sequence. Depending on the complexity of the tracker, it could track the face as a rigid object or as a complete deformable face model with face expressions. This report is based on the work of a real time feature based face tracker. Feature based means that you track certain features in the face, like points with special characteristics. It might be a mouth or eye corner, but theoretically it could be any point. For this tracker, the latter is of interest. Its task is to extract global parameters, i.e. rotation and translation, as well as dynamic facial parameters (expressions) for each frame. It tracks feature points using motion between frames and a textured face model (Candide). It then uses an extended Kalman filter to estimate the parameters from the tracked feature points.

Eye tracking technology has made it possible to accurately and consistently track a users gaze position on a screen. The human eyes center of focus, where it can see the most detailed information, is quite small at a given moment. The peripheral vision of humans have a much lower level of details than the center of gaze. Knowing this, it is possible to display a view that increases the level of resolution at the position of the users gaze point on the screen, while the rest of the screen keeps a lower resolution. An implementation of such a system can generate a representation of data with both detail and overview. The results indicate that even with simple gaze data processing it is possible to use gaze control to help explore details of a high resolution image. Gaze data processing often involve a compromise between stability, responsiveness and latency. A low latency, highly responsive gaze data filter would increase the risk for lens oscillation, and demand a higher concentration level from the viewer then a slower filter would. Applying a gaze data filter that allowed for smooth and stable lens movement for small saccades and responsive movements for large saccades proved successfully. With the uses of gaze control the user might be able to use a gaze aware application more efficient since gaze precedes actions. Gaze control would also reduce the need for hand motions which could provide a improved work environment for people interacting with computer.

En hundpejl är idag något absolut nödvändigt vid löshundsjakt. Anledningen är att jägaren måste veta vart hunden är och helst också vad som sker. Idag när trafiken ökar allt mer är det av vikt att i tid kunna avgöra om hunden är på väg mot en trafikerad väg. Om hunden blir still har man möjlighet att i tid avgöra om den fastnat eller har gått i vatten och har möjlighet att hinna fram i tid för att hjälpa. Och då hundpejlar ofta kostar mer än 2000 kronor så finns det ett önskemål om att ta fram billigare varianter av hundpejlar. Målet i detta projekt är därför att konstruera, montera och programmera en pejl av Arduino UNO och Adafruit FONA 808 som uppfyller de krav, såsom en batteritid på minst 8 timmar och ett precisionsfel på max 5 meter, som en jägare ställer på en pejl som samtidigt är billigare en kommersiell produkt med liknande prestanda. Tillgångavägssättet var sådant att först studerades relevant litteratur såsom Adafruits produktbeskrivning och testkod, sedan testades de olika enskilt funktionerna, skicka, ta bort och läsa SMS samt hämta GPS-koordinater. När det var klart att funktionerna fungerade programmerades en kod som erhåller de egenskaper som en användare önskar sig.  Därefter utvärderades pejlen för att se om den uppfyller de ställda kraven. Det som testades var pejlens vikt, batteritid och positionsnoggrannhet. Vikten mättes på en köksvåg, batteritiden mättes genom att testa batteriladdningen en gång i timmen över tre timmar och positionsnoggrannheten mättes på sådant sätt att pejlens koordinater jämfördes med resultatet från Google Maps och Eniro. Det visade sig att pejlen inte helt uppfyller alla krav, då positionsnoggrannheten inte direkt uppfyller de kraven som är ställda. Dock är enheten fortfarande användningsbar för spårning då den ger en tillräcklig generell area för att kunna hitta en hund på. Pejlen kan även användas i andra syften, till exempel placera den i en bil utifall stöld. Den ger även en bas att vidareutveckla en hundpejl ifrån till exempel skicka ljud till en telefon vilket även intresserar jägare. / A dog tracker is something that is essential when hunting with a dog. The reason is because the hunter needs to know where the dog is always, while preferably as well knowing what happens with the dog. Today, when the traffic is increasing and more, it is of importance to be able to determine whether the dog is heading for a busy road. The tracker also gives the hunter the possibility to rescue the dog if it gets stuck or fall in water. Dog trackers are of importance to the hunter, but they are also expensive, most costs more than 2000 SEK/230 USD, so there is a desire for a cheaper dog tracker that still fulfil the demands that hunters or dog owners require. The goal of this project is to design, build and program a dog tracker from Arduino UNO and Adafruit FONA 808, that meets the requirements stated by a user and at the same time are cheaper than the commercial equivalents. The method used are such that first relevant documents, such as Adafruit product description and testcode, are studied to gain an understanding of the units used. The units were then tested by the testcode to ensure that all parts are working correctly, this was done by testing read, delete and send SMS and get GPS-coordinates. When it was sure that all parts worked correctly a code was programmed that fulfilled all the requirements requested by a user. Then the finished dog tracker was evaluated to ensure that it fulfilled the requirements. Weight, battery time and positioning accuracy was tested, where weight was tested by a kitchen scale, battery time was tested by measuring the loss of charge once an hour over a period of three hours. From what was measured in those three hours a battery time was calculated by extrapolating loss of battery power/hour. The positioning accuracy was measured by using the dog trackers coordinates and comparing them to Google Maps and Eniro coordinates. The conclusion of the project is that the dog tracker didn’t fulfil all the requirements, its positioning accuracy didn’t reach the requirement of max 5-meter error. Though the dog tracker is still usable for tracking because it still gives a good enough positioning for finding a dog. The dog tracker can also be used for other purposes such as placing in a car to track it in event of a theft. The dog tracker also acts as a base for future developments, like using it to send sound which is also of interest for a hunter.