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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.
91

Towards the Design of Neural Network Framework for Object Recognition and Target Region Refining for Smart Transportation Systems

Zhao, Yiheng 13 August 2018 (has links)
Object recognition systems have significant influences on modern life. Face, iris and finger point recognition applications are commonly applied for the security purposes; ASR (Automatic Speech Recognition) is commonly implemented on speech subtitle generation for various videos and audios, such as YouTube; HWR (Handwriting Recognition) systems are essential on the post office for cheque and postcode detection; ADAS (Advanced Driver Assistance System) are well applied to improve drivers’, passages’ and pedestrians’ safety. Object recognition techniques are crucial and valuable for academia, commerce and industry. Accuracy and efficiency are two important standards to evaluate the performance of recognition techniques. Accuracy includes how many objects can be indicated in real scene and how many of them can be correctly classified. Efficiency means speed for system training and sample testing. Traditional object detecting methods, such as HOG (Histogram of orientated Gradient) feature detector combining with SVM (Support Vector Machine) classifier, cannot compete with frameworks of neural networks in both efficiency and accuracy. Since neural network has better performance and potential for improvement, it is worth to gain insight into this field to design more advanced recognition systems. In this thesis, we list and analyze sophisticated techniques and frameworks for object recognition. To understand the mathematical theory for network design, state-of-the-art networks in ILSVRC (ImageNET Large Scale Visual Recognition Challenge) are studied. Based on analysis and the concept of edge detectors, a simple CNN (Convolutional Neural Network) structure is designed as a trail to explore the possibility to utilize the network of high width and low depth for region proposal selection, object recognition and target region refining. We adopt Le-Net as the template, taking advantage of multi-kernels of GoogLe-Net. We made experiments to test the performance of this simple structure of the vehicle and face through ImageNet dataset. The accuracy for the single object detection is 81% in average and for plural object detection is 73.5%. We refined networks through many aspects to reach the final accuracy 95% for single object detection and 89% for plural object detection.
92

An infrastructure for secure distributed object-oriented databases

Dreyer, Lucas Cornelius Johannes 10 September 2012 (has links)
M.Sc. / In a society that is becoming increasingly reliant on information, it is necessary for information to be stored efficiently and safely. Database technology is used to store large chunks of information efficiently, while database security is concerned with storing information securely. More complex computer applications (CAD/CAM, multimedia and Groupware) led to then development of object-oriented programming, with object-oriented databases following shortly after. Object-oriented databases store the data of object-oriented systems efficiently and permanently. They provide a rich set of semantic structures that allows them to be used in applications where other database models are simply inadequate. In federations consisting of several interconnected databases, security plays a vital role in the proper management of information. This work describes a Secure Distributed Object Environment (SDOE) infrastructure. It is designed to be implementation-oriented, on which strict theoretic prototypes such as SPOP (Selfprotecting Object Prototype) can be built. SPOP is a prototype of a secure object-oriented database and is based on the SPO database model of Olivier. To describe federated database architectures (used by SDOE and SPOP), it is necessary to understand the architecture of federated database systems. Reference architectures for federated database systems are discussed first and a comparison is drawn between two prominent reference architectures. We proposed a generalised reference architecture based on these two architectures. created in order to make the use of object-oriented programming in a distributed environment as problem free as possible. A marshal buffer structure will be discussed thirdly. The latter structure is used to contain procedure parameters during an RPC (Remote Procedure Call). Fourthly, the communications infrastructure necessary to support higher-level services is discussed. The infrastructure is implemented in Linux (a UNIX variant), and this approach has provided several interesting challenges. The fifth discussion will deal with the requirements for a name service. A name service is necessary if objects were to be used transparently (without reference to their current locations in the federation).
93

Detection and tracking of unknown objects on the road based on sparse LiDAR data for heavy duty vehicles / Upptäckt och spårning av okända objekt på vägen baserat på glesa LiDAR-data för tunga fordon

Shilo, Albina January 2018 (has links)
Environment perception within autonomous driving aims to provide a comprehensive and accurate model of the surrounding environment based on information from sensors. For the model to be comprehensive it must provide the kinematic state of surrounding objects. The existing approaches of object detection and tracking (estimation of kinematic state) are developed for dense 3D LiDAR data from a sensor mounted on a car. However, it is a challenge to design a robust detection and tracking algorithm for sparse 3D LiDAR data. Therefore, in this thesis we propose a framework for detection and tracking of unknown objects using sparse VLP-16 LiDAR data which is mounted on a heavy duty vehicle. Experiments reveal that the proposed framework performs well detecting trucks, buses, cars, pedestrians and even smaller objects of a size bigger than 61x41x40 cm. The detection distance range depends on the size of an object such that large objects (trucks and buses) are detected within 25 m while cars and pedestrians within 18 m and 15 m correspondingly. The overall multiple objecttracking accuracy of the framework is 79%. / Miljöperception inom autonom körning syftar till att ge en heltäckande och korrekt modell av den omgivande miljön baserat på information från sensorer. För att modellen ska vara heltäckande måste den ge information om tillstånden hos omgivande objekt. Den befintliga metoden för objektidentifiering och spårning (uppskattning av kinematiskt tillstånd) utvecklas för täta 3D-LIDAR-data från en sensor monterad på en bil. Det är dock en utmaning att designa en robust detektions och spårningsalgoritm för glesa 3D-LIDAR-data. Därför föreslår vi ett ramverk för upptäckt och spårning av okända objekt med hjälp av gles VLP-16-LIDAR-data som är monterat på ett tungt fordon. Experiment visar att det föreslagna ramverket upptäcker lastbilar, bussar, bilar, fotgängare och även mindre objekt om de är större än 61x41x40 cm. Detekteringsavståndet varierar beroende på storleken på ett objekt så att stora objekt (lastbilar och bussar) detekteras inom 25 m medan bilar och fotgängare detekteras inom 18 m respektive 15 m på motsvarande sätt. Ramverkets totala precision för objektspårning är 79%.
94

Thermal-RGB Sensory Data for Reliable and Robust Perception

El Ahmar, Wassim 29 November 2023 (has links)
The significant advancements and breakthroughs achieved in Machine Learning (ML) have revolutionized the field of Computer Vision (CV), where numerous real-world applications are now utilizing state-of-the-art advancements in the field. Advanced video surveillance and analytics, entertainment, and autonomous vehicles are a few examples that rely heavily on reliable and accurate perception systems. Deep learning usage in Computer Vision has come a long way since it sparked in 2012 with the introduction of Alexnet. Convolutional Neural Networks (CNN) have evolved to become more accurate and reliable. This is attributed to the advancements in GPU parallel processing, and to the recent availability of large scale and high quality annotated datasets that allow the training of complex models. However, ML models can only be as good as the data they train on and the data they receive in production. In real-world environments, a perception system often needs to be able to operate in different environments and conditions (weather, lighting, obstructions, etc.). As such, it is imperative for a perception system to utilize information from different types of sensors to mitigate the limitations of individual sensors. In this dissertation, we focus on studying the efficacy of using thermal sensors to enhance the robustness of perception systems. We focus on two common vision tasks: object detection and multiple object tracking. Through our work, we prove the viability of thermal sensors as a complement, and in some scenarios a replacement, to RGB cameras. For their important applications in autonomous vehicles and surveillance, we focus our research on pedestrian and vehicle perception. We also introduce the world's first (to the best of our knowledge) large scale dataset for pedestrian detection and tracking including thermal and corresponding RGB images.
95

Perceptual Salience of Non-accidental Properties

Weismantel, Eric January 2013 (has links)
No description available.
96

Generalized Landmark Recognition in Robot Navigation

Zhou, Qiang January 2004 (has links)
No description available.
97

Graph-based Inference with Constraints for Object Detection and Segmentation

Ma, Tianyang January 2013 (has links)
For many fundamental problems of computer vision, adopting a graph-based framework can be straight-forward and very effective. In this thesis, I propose several graph-based inference methods tailored for different computer vision applications. It starts from studying contour-based object detection methods. In particular, We propose a novel framework for contour based object detection, by replacing the hough-voting framework with finding dense subgraph inference. Compared to previous work, we propose a novel shape matching scheme suitable for partial matching of edge fragments. The shape descriptor has the same geometric units as shape context but our shape representation is not histogram based. The key contribution is that we formulate the grouping of partial matching hypotheses to object detection hypotheses is expressed as maximum clique inference on a weighted graph. Consequently, each detection result not only identifies the location of the target object in the image, but also provides a precise location of its contours, since we transform a complete model contour to the image. We achieve very competitive results on ETHZ dataset, obtained in a pure shape-based framework, demonstrate that our method achieves not only accurate object detection but also precise contour localization on cluttered background. Similar to the task of grouping of partial matches in the contour-based method, in many computer vision problems, we would like to discover certain pattern among a large amount of data. For instance, in the application of unsupervised video object segmentation, where we need automatically identify the primary object and segment the object out in every frame. We propose a novel formulation of selecting object region candidates simultaneously in all frames as finding a maximum weight clique in a weighted region graph. The selected regions are expected to have high objectness score (unary potential) as well as share similar appearance (binary potential). Since both unary and binary potentials are unreliable, we introduce two types of mutex (mutual exclusion) constraints on regions in the same clique: intra-frame and inter-frame constraints. Both types of constraints are expressed in a single quadratic form. An efficient algorithm is applied to compute the maximal weight cliques that satisfy the constraints. We apply our method to challenging benchmark videos and obtain very competitive results that outperform state-of-the-art methods. We also show that the same maximum weight subgraph with mutex constraints formulation can be used to solve various computer vision problems, such as points matching, solving image jigsaw puzzle, and detecting object using 3D contours. / Computer and Information Science
98

3D Object Detection from Images

Simonelli, Andrea 28 September 2022 (has links)
Remarkable advancements in the field of Computer Vision, Artificial Intelligence and Machine Learning have led to unprecedented breakthroughs in what machines are able to achieve. In many tasks such as in Image Classification in fact, they are now capable of even surpassing human performance. While this is truly outstanding, there are still many tasks in which machines lag far behind. Walking in a room, driving on an highway, grabbing some food for example. These are all actions that feel natural to us but can be quite unfeasible for them. Such actions require to identify and localize objects in the environment, effectively building a robust understanding of the scene. Humans easily gain this understanding thanks to their binocular vision, which provides an high-resolution and continuous stream of information to our brain that efficiently processes it. Unfortunately, things are much different for machines. With cameras instead of eyes and artificial neural networks instead of a brain, gaining this understanding is still an open problem. In this thesis we will not focus on solving this problem as a whole, but instead delve into a very relevant part of it. We will in fact analyze how to make ma- chines be able to identify and precisely localize objects in the 3D space by relying only on visual input i.e. 3D Object Detection from Images. One of the most complex aspects of Image-based 3D Object Detection is that it inherently requires the solution of many different sub-tasks e.g. the estimation of the object’s distance and its rotation. A first contribution of this thesis is an analysis of how these sub-tasks are usually learned, highlighting a destructivebehavior which limits the overall performance and the proposal of an alternative learning method that avoids it. A second contribution is the discovery of a flaw in the computation of the metric which is widely used in the field, affecting the re-computation of the performance of all published methods and the introduction of a novel un-flawed metric which has now become the official one. A third contribution is focused on one particular sub-task, i.e. estimation of the object’s distance, which is demonstrated to be the most challenging. Thanks to the introduction of a novel approach which normalizes the appearance of objects with respect to their distance, detection performances can be greatly improved. A last contribution of the thesis is the critical analysis of the recently proposed Pseudo-LiDAR methods. Two flaws in their training protocol have been identified and analyzed. On top of this, a novel method able to achieve state-of-the-art in Image-based 3D Object Detection has been developed.
99

Features identification and tracking for an autonomous ground vehicle

Nguyen, Chuong Hoang 14 June 2013 (has links)
This thesis attempts to develop features identification and tracking system for an autonomous ground vehicle by focusing on four fundamental tasks: Motion detection, object tracking, scene recognition, and object detection and recognition. For motion detection, we combined the background subtraction method using the mixture of Gaussian models and the optical flow to highlight any moving objects or new entering objects which stayed still. To increase robustness for object tracking result, we used the Kalman filter to combine the tracking method based on the color histogram and the method based on invariant features. For scene recognition, we applied the algorithm Census Transform Histogram (CENTRIST), which is based on Census Transform images of the training data and the Support Vector Machine classifier, to recognize a total of 8 scene categories. Because detecting the horizon is also an important task for many navigation applications, we also performed horizon detection in this thesis. Finally, the deformable parts-based models algorithm was implemented to detect some common objects, such as humans and vehicles. Furthermore, objects were only detected in the area under the horizon to reduce the detecting time and false matching rate. / Master of Science
100

Object-Oriented Design of a Windows™ Based Automated Telemetry System

Self, Lance P. L. 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / This paper illustrates a Windows computer application program which uses the object-oriented paradigm as a basis. The objective of the application program is to control the setup of equipment involved in routing a telemetry signal. This design uses abstract classes as high level building blocks from which site specific classes are derived. It is the next generation to the software portion of a system described by Eugene L. Law. The object-oriented design method, as presented by Grady Booch in his book Object-Oriented Analysis and Design with Applications, is the design tool.

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