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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.
1

Two-Tail Non-Linear Moving Tape Displays

January 2012 (has links)
abstract: Fixed-pointer moving-scale tape displays are a compact way to present wide range dynamic data, and are commonly employed in aircraft and spacecraft to display the primary parameters of airspeed, altitude and heading. A limitation of the moving tape format is its inability to natively display off scale target, reference or 'bug' values. The hypothesis tested was that a non-linear fisheye presentation (made possible by modern display technology) would maintain the essential functionality and compactness of existing moving tape displays while increasing situational awareness by ecologically displaying a wider set of reference values. Experimentation showed that the speed and accuracy of reading the center system value was not significantly changed with two types of expanded range displays. The limited situational awareness tests did not show a significant improvement with the new displays, but since no functionality was degraded further testing of expanded range displays may be productive. / Dissertation/Thesis / M.S. Applied Psychology 2012
2

Improving memorability in fisheye views

Skopik, Amy Caroline 01 September 2004
Interactive fisheye views use distortion to show both local detail and global context in the same display space. Although fisheyes allow the presentation and inspection of large data sets, the distortion effects can cause problems for users. One such problem is lack of memorability the ability to find and go back to objects and features in the data. This thesis examines the possibility of improving the memorability of fisheye views by adding historical information to the visualization. The historical information is added visually through visit wear, an extension of the concepts of edit wear and read wear. This will answer the question Where have I been? through visual instead of cognitive processing by overlaying new visual information on the data to indicate a users recent interaction history. This thesis describes general principles of visibility in a space that is distorted by a fisheye lens and defines some parameters of the design space of visit wear. Finally, a test system that applied the principles was evaluated, and showed that adding visit wear to a fisheye system improved the memorability of the information space.
3

Improving memorability in fisheye views

Skopik, Amy Caroline 01 September 2004 (has links)
Interactive fisheye views use distortion to show both local detail and global context in the same display space. Although fisheyes allow the presentation and inspection of large data sets, the distortion effects can cause problems for users. One such problem is lack of memorability the ability to find and go back to objects and features in the data. This thesis examines the possibility of improving the memorability of fisheye views by adding historical information to the visualization. The historical information is added visually through visit wear, an extension of the concepts of edit wear and read wear. This will answer the question Where have I been? through visual instead of cognitive processing by overlaying new visual information on the data to indicate a users recent interaction history. This thesis describes general principles of visibility in a space that is distorted by a fisheye lens and defines some parameters of the design space of visit wear. Finally, a test system that applied the principles was evaluated, and showed that adding visit wear to a fisheye system improved the memorability of the information space.
4

Contribution à la Perception Visuelle Basée Caméras Grand Angle pour la Robotique Mobile et Les Véhicules Autonomes / Contribution to wide angle visual perception for mobile robots and self driving cars

Khomutenko, Bogdan 15 June 2018 (has links)
Ce travail de thèse présente un nouveau modèle de projection pour les cameras fisheye, qui est mathématiquement simple et pourtant montre une haute précision une fois appliqué aux caméras réelles. Les propriétés géométriques de ce modèle ont été analysées en utilisant le concept de surface de projection, introduit dans ce travail. En particulier, une inverse analytique de ce modèle a été établie, ainsi qu'une équation implicite des projections de lignes droites. Cette dernière nous a permis de développer une méthode de reconstruction 3D directe basée vision pour les caméras fisheye sans rectifier les images. Cela a été fait grâce à une algorithme de rastérisation de courbes implicites. Cet algorithme de reconstruction nous permet d'employer le Semi-Global Matching pour obtenir une reconstruction 3D précise. Tous ces éléments ont été employés dans un système de localisation visuelle directe avec deux méthodes de recalage d'images : minimisation d'erreur photométrique et maximisation d'information mutuelle. L'étalonnage intrinsèque et extrinsèque d'un robot mobile équipé de caméras fisheye a été considéré et une toolbox d'étalonnage a été développée. / This thesis presents a novel projection model for fisheye cameras, which is mathematically simple and yet shows a high precision when applied to real cameras. Geometric properties of the model have been analyzed using the concept of projection surface, introduced in this work. In particular, a closed-form inverse mapping and an implicit equation for straight line projection have been found. This fact has been used to develop a method of direct stereo correspondence on raw fisheye images via rasterization of implicit curve. This correspondence algorithm allows us to apply the Semi-Global Matching algorithm to get an accurate 3D reconstruction using fisheye stereo systems. All these elements have been shown to be applicable to a direct visual localization system with two different methods of image registration: direct photometric error minimization and mutual information maximization. Intrinsic and extrinsic calibration of a mobile robot with fisheye cameras has been considered and a toolbox for such a calibration has been developed.
5

Photographic Fisheye Lens Design for 35mm Format Cameras

Yan, Yufeng January 2016 (has links)
Fisheye lenses refer to ultra-wide angle lenses that have field of view equal or larger than 180 degrees. Such lenses introduce large amount of barrel distortion to capture at least the entire hemisphere in front of the lens. Fisheye lenses were initially designed for scientific use, such as cloud recording and angle measuring, and were widely used for commercial purposes later. The development of photographic fisheye lenses started in 1960s. However, the lack of detailed references on photographic fisheye lens design makes such design challenging. This thesis provides detailed introduction of photographic fisheye lens design for 35mm format DSLR cameras. A discussion on the history of fisheye lenses is provided to describe the development of fisheye lenses. The tangential and sagittal magnifications are mathematically derived for each fisheye lens projection mapping method to show their differences. The special properties and design issues of photographic fisheye lenses are described in detail. Along with each design issue, some solutions suggested by the author are also provided. The performance of the current diagonal fisheye lenses for 35mm DSLR cameras are evaluated in detail. Then a new diagonal fisheye lens designed by the author is presented and compared with the current diagonal fisheye lenses on the market. Finally, a zoom fisheye lens designed for 35mm DSLR cameras is presented and discussed.
6

Utvärdering av en visualiseringsteknik för navigering i stora datamängder

Ericsson, Jonas January 1997 (has links)
<p>Målet med detta examensarbete är att ta fram ett gränsnitt för navigering i stora datamängder samt undersöka eventuella styrkor och svagheter hos detta gränsnitt. Bakgrunden till projektet är att företaget Analog Software utvecklar ett system som automatiskt skall klassificera objekt i en datamängd och sedan presentera denna klassificerade datamängd.</p><p>Gränsnittet skall stödja en informationssökningsstrategi som benämns ”browsing”. En teknik för visualisering av information som varit framgångsrik är den så kallade ”Fisheye-tekniken” som baseras på en analogi med en vidvinkellins. Tekniken visar lokal information med hög detaljrikedom samtidigt som den visar global information med låg detaljrikedom.</p><p>Ett flertal gränssnitt har använt sig av denna teknik för visualisering av information. I detta arbete har ett textbaserat Fisheye-gränssnitt tagits fram och testat med avseende på två olika funktioner. De två funktionerna är ”anomalier” och ”stöd för bokmärken”.</p><p>Hypoteserna var:</p><p>1. Om anomalier fanns i datastrukturen så skulle en Fisheye-teknik förstärka dessa.</p><p>2. En bokmärkesfunktion skall ej behövas då Fisheye-tekniken erbjuder global kontext och byte av fokus går snabbt.</p><p>Två experiment utfördes med 28 försökspersoner. I experiment 1 använde hälften av försökspersonerna ett standargränssnitt och hälften ett Fisheye-gränssnitt. De fick navigera i en datamängd sorterad på två olika sätt och ange om det upplevde sorteringen som naturlig eller konstig.</p><p>I experimet 2 ingick samma försökspersoner som i experiment 1. I detta experiment fick hälften navigera med ett Fisheye-gränsnitt med bokmärkesfunktion och hälften med ett Fisheye-gränssnitt utan bokmärkesfunktion. De skulle navigera i en datamängd och svara på ett antal frågor.</p><p>Resultaten visade att Hypotes 1 kunde förkastas. Försökspersonerna som använde sig av Fisheye-gränsittet upplevde datamängden att vara mer naturlig än den grupp som använt sig av ett standardgränssnitt. För hypotes 2 kunde inga säkra slutsatser dra på grund av att experimentet inte lyckades mäta det som avsågs att mätas.</p>
7

Investigation of fisheye lenses for small UAV aerial photography

Gurtner, Alex January 2008 (has links)
Aerial photography obtained by UAVs (Unmanned Aerial Vehicles) is an emerging market for civil applications. Small UAVs are believed to close gaps in niche markets, such as acquiring airborne image data for remote sensing purposes. Small UAVs will be able to fly at low altitudes, in dangerous environments and over long periods of time. However, the small lightweight constructions of these UAVs lead to new problems, such as higher agility leading to more susceptibility to turbulence and limitations in space and payload for sensor systems. This research investigates the use of low-cost fisheye lenses to overcome such problems which theoretically makes the airborne imaging less sensitive to turbulence. The fisheye lens has the benet of a large observation area (large field of view) and doesn't add additional weight to the aircraft, like traditional mechanical stabilizing systems. This research presents the implementation of a fisheye lens for aerial photography and mapping purposes, including theoretical background of fisheye lenses. Based on the unique feature of the distortion being a function of the viewing angle, methods used to derive the fisheye lens distortion are presented. The lens distortion is used to rectify the fisheye images before these images can be used in aerial photography. A detailed investigation into the inner orientation of the camera and inertial sensor is given, as well as the registration of airborne collected images. It was found that the attitude estimation is critical towards accurate mapping using low quality sensors. A loosely coupled EKF filter applied to the GPS and inertial sensor data estimated the attitude to an accuracy of 3-5° (1-sigma) using low-cost sensors typically found in small UAVs. However, the use of image stitching techniques may improve the outcome. On the other hand, lens distortion caused by the fisheye lens can be addressed by rectification techniques and removed to a sub-pixel level. Results of the process present image sequences gathered from a piloted aircraft demonstrating the achieved performance and potential applications towards UAVs. Further, an unforeseen issue with a vibrating part in the lens lead to the need for vibration compensation. The vibration could be estimated to ±1 pixel in 75% of the cases by applying an extended Hough transform to the fisheye images.
8

Fisheye Camera Calibration and Applications

January 2014 (has links)
abstract: Fisheye cameras are special cameras that have a much larger field of view compared to conventional cameras. The large field of view comes at a price of non-linear distortions introduced near the boundaries of the images captured by such cameras. Despite this drawback, they are being used increasingly in many applications of computer vision, robotics, reconnaissance, astrophotography, surveillance and automotive applications. The images captured from such cameras can be corrected for their distortion if the cameras are calibrated and the distortion function is determined. Calibration also allows fisheye cameras to be used in tasks involving metric scene measurement, metric scene reconstruction and other simultaneous localization and mapping (SLAM) algorithms. This thesis presents a calibration toolbox (FisheyeCDC Toolbox) that implements a collection of some of the most widely used techniques for calibration of fisheye cameras under one package. This enables an inexperienced user to calibrate his/her own camera without the need for a theoretical understanding about computer vision and camera calibration. This thesis also explores some of the applications of calibration such as distortion correction and 3D reconstruction. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2014
9

A Vision-Based Distance Estimation System for Flying Copters

Li, Zetong 16 September 2020 (has links)
Currently, as one of the most popular technologies being discussed and experimented, the application of flying copters in different industries is facing an obvious barrier; which is how to avoid obstacles while flying. One of the industries among all is small-sized package delivery business, which is also the master topic of a series of experiments. The most popular designs that have used for the Flying Copter Obstacle Avoidance System such as lidar scanners and infrared rangefinders are significantly accurate. However, with the heavyweight, expensive price and higher power consumption, these systems cannot be put into mass production. To reduce the cost and power consumption of the Obstacle Avoidance System, an innovative vision-based low-cost Obstacle Distance Estimation System for flying copters is demonstrated in this thesis. The Fisheye Lens Camera is used to provide a broader detection range and accurate results. Compared to other standard vision-based systems, the Fish Lens Camera Distance Estimation System can provide (around 360 degrees) extensive view for obstacle detection. Through the parallax pictures captured by the camera and the trigonometric rules, the system can estimate the distance to the target obstacle with reasonable results.
10

Visualiseringsverktyg för migrerad kod : Ersättare till Guardien

Eriksson, John, Karlsson, Tobias January 2019 (has links)
Java is one of the most widely used programming languages used today. CSN that previously used 4 GL tool should now migrate to Java development, which means that there is a need for a tool to show dependencies and relationships in the migrated and newly developed Java code. The GuardIEn was previously used in the old code base, but that tool will be wound up after CSN's after migration to Java. The overall purpose of the project is to create a graph database with data that is scanned with the tool jqAssistant. This database is then used by a Java backend that retrieves relationships and nodes from the graph database which is then used with a separate web interface in Angular to visualize all relations between program code / Java är en av de mest använda programmeringsspråken som används idag. CSN som tidigare använt 4 GL verktyg skall nu migrera till Java-utveckling vilket innebär att det finns ett behov av ett verktyg för att visa beroenden och relationer i den migrerade och nyutvecklade Java-koden. GuardIEn användes innan för detta i den gamla kodbasen men det verktyget kommer avvecklas efter CSN:s efter migrering till Java. Projektets övergripande syfte är att skapa en grafdatabas med data som skannas in med verktyget jqAssistant. Denna databas används sedan av en backend applikation som hämtar relationer och noder från grafdatabasen som sedan används med ett eget webbgränssnitt i Angular för visualisera alla relationer mellan programkod. Det har också undersökts kring funktioner på att söka efter programkod och filnamn i kodbasen för att hitta och kunna visa källkoden.

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