85 research outputs found

    Seguimento de pessoas com drones em espaços inteligentes

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    Recent technological progress made over the last decades in the field of Computer Vision has introduced new methods and algorithms with ever increasing performance results. Particularly, the emergence of machine learning algorithms enabled class based object detection on live video feeds. Alongside these advances, Unmanned Aerial Vehicles (more commonly known as drones), have also experienced advancements in both hardware miniaturization and software optimization. Thanks to these improvements, drones have emerged from their military usage based background and are now both used by the general public and the scientific community for applications as distinct as aerial photography and environmental monitoring. This dissertation aims to take advantage of these recent technological advancements and apply state of the art machine learning algorithms in order to create a Unmanned Aerial Vehicle (UAV) based network architecture capable of performing real time people tracking through image detection. To perform object detection, two distinct machine learning algorithms are presented. The first one uses an SVM based approach, while the second one uses an Convolutional Neural Network (CNN) based architecture. Both methods will be evaluated using an image dataset created for the purposes of this dissertation’s work. The evaluations performed regarding the object detectors performance showed that the method using a CNN based architecture was the best both in terms of processing time required and detection accuracy, and therefore, the most suitable method for our implementation. The developed network architecture was tested in a live scenario context, with the results showing that the system is capable of performing people tracking at average walking speeds.O recente progresso tecnológico registado nas últimas décadas no campo da Visão por Computador introduziu novos métodos e algoritmos com um desempenho cada vez mais elevado. Particularmente, a criação de algoritmos de aprendizagem automática tornou possível a detecção de objetos aplicada a feeds de vídeo capturadas em tempo real. Paralelo com este progresso, a tecnologia relativa a veículos aéreos não tripulados, ou drones, também beneficiaram de avanços tanto na miniaturização dos seus componentes de hardware assim como na optimização do software. Graças a essas melhorias, os drones emergiram do seu passado militar e são agora usados tanto pelo público em geral como pela comunidade científica para aplicações tão distintas como fotografia e monitorização ambiental. O objectivo da presente dissertação pretende tirar proveito destes recentes avanços tecnológicos e aplicar algoritmos de aprendizagem automática de última geração para criar um sistema capaz de realizar seguimento automático de pessoas com drones através de visão por computador. Para realizar a detecção de objetos, dois algoritmos distintos de aprendizagem automática são apresentados. O primeiro é dotado de uma abordagem baseada em Support Vector Machine (SVM), enquanto o segundo é caracterizado por uma arquitetura baseada em Redes Neuronais Convolucionais. Ambos os métodos serão avaliados usando uma base de dados de imagens criada para os propósitos da presente dissertação. As avaliações realizadas relativas ao desempenho dos algoritmos de detecção de objectos demonstraram que o método baseado numa arquitetura de Redes Neuronais Covolucionais foi o melhor tanto em termos de tempo de processamento médio assim como na precisão das detecções, revelando-se portanto, como sendo o método mais adequado de acordo com os objectivos pretendidos. O sistema desenvolvido foi testado num contexto real, com os resultados obtidos a demonstrarem que o sistema é capaz de realizar o seguimento de pessoas a velocidades comparáveis a um ritmo normal humano de caminhada.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

    Vision-Aided Navigation for GPS-Denied Environments Using Landmark Feature Identification

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    In recent years, unmanned autonomous vehicles have been used in diverse applications because of their multifaceted capabilities. In most cases, the navigation systems for these vehicles are dependent on Global Positioning System (GPS) technology. Many applications of interest, however, entail operations in environments in which GPS is intermittent or completely denied. These applications include operations in complex urban or indoor environments as well as missions in adversarial environments where GPS might be denied using jamming technology. This thesis investigate the development of vision-aided navigation algorithms that utilize processed images from a monocular camera as an alternative to GPS. The vision-aided navigation approach explored in this thesis entails defining a set of inertial landmarks, the locations of which are known within the environment, and employing image processing algorithms to detect these landmarks in image frames collected from an onboard monocular camera. These vision-based landmark measurements effectively serve as surrogate GPS measurements that can be incorporated into a navigation filter. Several image processing algorithms were considered for landmark detection and this thesis focuses in particular on two approaches: the continuous adaptive mean shift (CAMSHIFT) algorithm and the adaptable compressive (ADCOM) tracking algorithm. These algorithms are discussed in detail and applied for the detection and tracking of landmarks in monocular camera images. Navigation filters are then designed that employ sensor fusion of accelerometer and rate gyro data from an inertial measurement unit (IMU) with vision-based measurements of the centroids of one or more landmarks in the scene. These filters are tested in simulated navigation scenarios subject to varying levels of sensor and measurement noise and varying number of landmarks. Finally, conclusions and recommendations are provided regarding the implementation of this vision-aided navigation approach for autonomous vehicle navigation systems

    Swarming Reconnaissance Using Unmanned Aerial Vehicles in a Parallel Discrete Event Simulation

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    Current military affairs indicate that future military warfare requires safer, more accurate, and more fault-tolerant weapons systems. Unmanned Aerial Vehicles (UAV) are one answer to this military requirement. Technology in the UAV arena is moving toward smaller and more capable systems and is becoming available at a fraction of the cost. Exploiting the advances in these miniaturized flying vehicles is the aim of this research. How are the UAVs employed for the future military? The concept of operations for a micro-UAV system is adopted from nature from the appearance of flocking birds, movement of a school of fish, and swarming bees among others. All of these natural phenomena have a common thread: a global action resulting from many small individual actions. This emergent behavior is the aggregate result of many simple interactions occurring within the flock, school, or swarm. In a similar manner, a more robust weapon system uses emergent behavior resulting in no weakest link because the system itself is made up of simple interactions by hundreds or thousands of homogeneous UAVs. The global system in this research is referred to as a swarm. Losing one or a few individual unmanned vehicles would not dramatically impact the swarms ability to complete the mission or cause harm to any human operator. Swarming reconnaissance is the emergent behavior of swarms to perform a reconnaissance operation. An in-depth look at the design of a reconnaissance swarming mission is studied. A taxonomy of passive reconnaissance applications is developed to address feasibility. Evaluation of algorithms for swarm movement, communication, sensor input/analysis, targeting, and network topology result in priorities of each model\u27s desired features. After a thorough selection process of available implementations, a subset of those models are integrated and built upon resulting in a simulation that explores the innovations of swarming UAVs

    Vision Based Displacement Detection for Stabilized UAV Control on Cloud Server

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    Audio-Based Drone Detection and Identification Using Deep Learning Techniques with Dataset Enhancement through Generative Adversarial Networks

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    Drones are becoming increasingly popular not only for recreational purposes but in day-to-day applications in engineering, medicine, logistics, security and others. In addition to their useful applications, an alarming concern in regard to the physical infrastructure security, safety and privacy has arisen due to the potential of their use in malicious activities. To address this problem, we propose a novel solution that automates the drone detection and identification processes using a drone’s acoustic features with different deep learning algorithms. However, the lack of acoustic drone datasets hinders the ability to implement an effective solution. In this paper, we aim to fill this gap by introducing a hybrid drone acoustic dataset composed of recorded drone audio clips and artificially generated drone audio samples using a state-of-the-art deep learning technique known as the Generative Adversarial Network. Furthermore, we examine the effectiveness of using drone audio with different deep learning algorithms, namely, the Convolutional Neural Network, the Recurrent Neural Network and the Convolutional Recurrent Neural Network in drone detection and identification. Moreover, we investigate the impact of our proposed hybrid dataset in drone detection. Our findings prove the advantage of using deep learning techniques for drone detection and identification while confirming our hypothesis on the benefits of using the Generative Adversarial Networks to generate real-like drone audio clips with an aim of enhancing the detection of new and unfamiliar drones
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