Comunicações ópticas por câmera para sistemas de assistência à condução

Communications, whatever its type, is a pillar of our modern society. More specifically, communications by visible light, that show numerous advantages, from electromagnetic spectral efficiency and regulation freedom to energy saving (since it combine illumination and communication). As such, the automotive world is interested in this technology, in particularly, its application into the Intelligent Transport System (ITS). The objective of this work relies on the study and development of a demonstrator able to support VLC communication means in V2V (Vehicle to Vehicle) scenario, making use of the LED luminaries already implemented in nowadays cars. Since the outdoor implementation is one of the requirements, reception based in OCC (Optical Camera Communication) is a viable solution in this conditions. Also the signal processing/decoding is performed by a CNN (Convolutional Neural Network), this type of algorithm shows a huge decoding flexibility and resilience, which benefits the transmission system performance. All the project was done in collaboration with the integrated circuits systems group of Instituto de Telecomunicações de Aveiro and Exatronic Lda company, based in Aveiro and specialized in innovation and investigation (I+I), engineering and manufacturing of electronics.As comunicações, qualquer que seja o seu tipo, mostram-se como um pilar fundamental para a sociedade. Especificamente as comunicações por luz visível, que apresentam inúmeras vantagens, desde a eficiência espectral e mais liberdade de regulamentação, até à energética pois alia duas caracteristicas distintas (iluminação e comunicação) numa só. Como tal, o mundo automóvel apresenta-se como um dos posíveis interessados na aplicação desta tecnologia, mais propriamente a aplicação como parte integrante do sistema inteligente de transportes (ITS). Este trabalho tem como objectivo o estudo e desenvolvimento de um demonstrador capaz de estabelecer um link de comunicação V2V (Vehicle to vehicle) por meio da modulação da luz visivel emitida pelas iluminárias LED já equipadas actualmente nos veículos. Sendo a implementação exterior um dos requerimentos deste sistema, a rececção através de OCC (Optical Camera Communication) mostra-se assim uma solução viável. Assim como o processamento do sinal recebido, que é efectuado por meio de CNNs (Convolutional Neural Networks), que mostram flexibilidade e resiliência, o que benefecia a capacidade do sistema de transmissão. Todo o projecto foi realizado em colaboração com o grupo de circuitos integrados do Instituto de Telecomunicações de Aveiro e a empresa Exatronic Lda, sediada em Aveiro, e especializada em inovação, investigação (I+I), engenharia e produção de eletrónica.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Experimental demonstration of RGB LED-based optical camera communications

Red, green, and blue (RGB) light-emitting diodes (LEDs) are widely used in everyday illumination, particularly where color-changing lighting is required. On the other hand, digital cameras with color filter arrays over image sensors have been also extensively integrated in smart devices. Therefore, optical camera communications (OCC) using RGB LEDs and color cameras is a promising candidate for cost-effective parallel visible light communications (VLC). In this paper, a single RGB LED-based OCC system utilizing a combination of undersampled phase-shift on off keying (UPSOOK), wavelength-division multiplexing (WDM), and multiple-input multiple-output (MIMO) techniques is designed, which offers higher space efficiency (3 bits/Hz/LED), long-distance, and nonflickering VLC data transmission. A proof-of-concept test bed is developed to assess the bit-error-rate performance of the proposed OCC system. The experimental results show that the proposed system using a single commercially available RGB LED and a standard 50-frame/s camera is able to achieve a data rate of 150 bits/s over a range of up to 60 m

Vehicular Visible Light Communications

Vehicular communications are foreseen to play a key role to increase road safety and realize autonomous driving. In addition to the radio frequency (RF)-based dedicated short range communication (DSRC) and long-term evolution (LTE) communication technologies, vehicular visible light communication (V2LC) is proposed as a complementary solution, utilizing readily deployed vehicle light emitting diode (LED) lights as transmitter with image sensors such as photodetector (PD) and camera as the receivers. V2LC fundamentals including transmitter and receiver characteristics with dimming capabilities are reviewed in this chapter. Depending on the field measurements using off-the-shelf automotive LED light, communication constraints are demonstrated. Moreover, considering the line-of-sight (LoS) characteristics, security aspects of V2LC is compared with the DSRC for a practical vehicle-to-vehicle (V2V) communication scenario. Finally, superiority of V2LC in terms of communication security with the proposed SecVLC method is demonstrated through simulation results

Impacts on Multi-pulse Pulse Position Modulation Visible Light Communication from Outdoor Daylight Conditions

The growing deployment of light-emitting diodes as energy-efficient, cost-effective lighting for vehicles opens opportunities for visible light vehicle-to-vehicle communication. Leveraging existing headlights and taillights on cars for inter-vehicle communication offers an opportunity to save on both hardware costs and the use of the congested radio frequency spectrum. However, most vehicle-to-vehicle visible light communication investigations in the literature have been limited in range. This paper presents an overview of the factors impacting outdoor visible light communications at increasing distances and presents findings from outdoor testing at ranges approaching 200 m. Using software spatial filtering and multi-pulse pulse position modulation, strong throughput is shown at 50 m in daylight conditions, with improving symbol error rates achieved in outdoor daylight conditions at 100 m by increasing intensity modulation

A Multi-Hop Relay Based Routing Algorithm for Vehicular Visible Light Communication Networks

The use of visible light communications (VLC) in intelligent transportation systems is becoming highly popular. In this paper, we present a predictionbased channel gain model and propose a multi-hop relaybased routing algorithm for vehicular VLC communication networks. Using the surrogate modeling lab platform SUMO and Matlab we show that, a stationary velocity of vehicles is better suited to form a good prediction, while the proposed routing algorithm offers improved signal-to-noise ratio

Performance of Vehicular Visible Light Communications under the Effects of Atmospheric Turbulence with Aperture Averaging

In this paper, we investigate the performance of a vehicular visible light communications (VVLC) link with a non-collimated and incoherent light source (a light-emitting diode) as the transmitter (Tx), and two different optical receiver (Rx) types (a camera and photodiode (PD)) under atmospheric turbulence (AT) conditions with aperture averaging (AA). First, we present simulation results indicating performance improvements in the signal-to-noise ratio (SNR) under AT with AA with increasing size of the optical concentrator. Experimental investigations demonstrate the potency of AA in mitigating the induced signal fading due to the weak to moderate AT regimes in a VVLC system. The experimental results obtained with AA show that the link’s performance was stable in terms of the average SNR and the peak SNR for the PD and camera-based Rx links, respectively with <1 dB SNR penalty for both Rxs, as the strength of AT increases compared with the link with no AT

Comunicações com câmara para aplicações de platooning

Platooning is a technology that corresponds to all the coordinated movements of a collection of vehicles, or, in the case of mobile robotics, to all the coordinated movements of a collection of mobile robots. It brings several advantages to driving, such as, improved safety, accurate speed control, lower CO2 emission rates, and higher energy efficiency. This dissertation describes the development of a laboratory scale demonstrator of platooning based on optical camera communications, using two generic wheel steered robots. For this purpose, one of the robots is equipped with a Light Emitting Diode (LED) matrix and the other with a camera. The LED matrix acts as an Optical Camera Communication (OCC) transmitter, providing status information of the robot attitude. The camera acts as both image acquisition and as an OCC receiver. The gathered information is processed using the algorithm You Only Look Once (YOLO) to infer the robot motion. The YOLO object detector continuously checks the movement of the robot in front. Performance evaluation of 5 different YOLO models (YOLOv3, YOLOv3-tiny, YOLOv4, YOLOv4-tiny, YOLOv4-tiny-3l) was conducted to assess which model works best for this project. The outcomes demonstrate that YOLOv4-tiny surpasses the other models in terms of timing, making it the ideal choice for real-time performance. Object detection using YOLOv4-tiny was performed on the computer. This was chosen since it has a processing speed of 3.09 fps as opposed to the Raspberry Pi’s 0.2 fps.O platooning é uma tecnologia que corresponde a todas as movimentações coordenadas de um conjunto de veículos, ou, no caso da robótica movel, a todas as movimentações coordenadas de um conjunto de robots móveis. Traz várias vantagens para a condução, tais como, maior segurança, um controlo preciso da velocidade, menores taxas de emissão de CO2 e maior eficiência energética. Esta dissertação descreve o desenvolvimento de um demonstrador de platooning em escala laboratorial baseado em comunicações com câmera, usando dois robôs móveis genéricos. Para este propósito, um dos robôs é equipado com uma matriz de Light Emitting Diodes (LEDs) e o outro é equipado com uma câmera. A matriz de LEDs funciona como transmissor, fornecendo informações de estado do robô. A câmera funciona como recetor, realizando a aquisição de imagens. As informações recolhidas são processadas usando o algoritmo You Only Look Once (YOLO) de forma a prever o movimento do robô. O YOLO verifica continuamente o movimento do robô da frente. A avaliação de desempenho de 5 modelos de YOLO diferentes (YOLOv3, YOLOv3-tiny, YOLOv4, YOLOv4-tiny, YOLOv4-tiny-3l) foi realizada para identificar qual o modelo que funciona melhor no contexto deste projeto. Os resultados demonstram que o YOLOv4-tiny supera os outros modelos em termos de tempo, tornando-o a escolha ideal para desempenho em tempo real. A deteção de objetos usando YOLOv4-tiny foi realizada no computador. Esta escolhe deveuse ao facto de o computador ter uma velocidade de processamento de 3,09 fps em oposição aos 0,2 fps da Raspberry Pi.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Light sensor development for ARA platform

Some years ago Google announced the ARA initiative. This consist on a modular phone where parts of the phone, like cameras, sensors or networks can be changed. So when a new feature appears or requiered by the user it is not needed to change the mobile phone, just to buy the modules with the functionality. See https://www.youtube.com/watch?v=2pr9cV6lvws for further information. The Wireless Networks Group will receive in December a developement kit (http://projectara.com/s/ProjectAraSpiral1DeveloperHardwareManual.pdf), to start working with it on January. The PFC or MasteDuring the last years, Visible Light Communication (VLC), a novel technology that enables standard Light-Emitting-Diodes (LEDs) to transmit data, is gaining significant attention. In the near future, this technology could enable devices containing LEDs – such as car lights, city lights, screens and home appliances – to carry information or data to the end-users, using their smartphone. However, VLC is currently limited by the end-point receiver, such as a the mobile camera, or a peripheral connected through the jack input and to unleash the full potential of VLC, more advanced receiver are required. On other, few year ago, Google ATAP - the Google innovation department - announced the ARA initiative. This consist on a modular phone where parts of the phone, like cameras, sensors or networks can be changed. So when a new feature appears or required by the user it is not needed to change the mobile phone, just to buy the modules with the functionality. This Master Thesis presents the design and development of a simple module that will support communication by light (VLC) using the ARA Module Developer Kit provided by Google. It consists on building a front-end circuit, connecting a photodiode that receives the level of light and use it as data carrier, in order to receive and display data inside a custom Android application on the ARA smartphone