Multimodal perception for autonomous driving

Mención Internacional en el título de doctorAutonomous driving is set to play an important role among intelligent transportation systems in the coming decades. The advantages of its large-scale implementation –reduced accidents, shorter commuting times, or higher fuel efficiency– have made its development a priority for academia and industry. However, there is still a long way to go to achieve full self-driving vehicles, capable of dealing with any scenario without human intervention. To this end, advances in control, navigation and, especially, environment perception technologies are yet required. In particular, the detection of other road users that may interfere with the vehicle’s trajectory is a key element, since it allows to model the current traffic situation and, thus, to make decisions accordingly. The objective of this thesis is to provide solutions to some of the main challenges of on-board perception systems, such as extrinsic calibration of sensors, object detection, and deployment on real platforms. First, a calibration method for obtaining the relative transformation between pairs of sensors is introduced, eliminating the complex manual adjustment of these parameters. The algorithm makes use of an original calibration pattern and supports LiDARs, and monocular and stereo cameras. Second, different deep learning models for 3D object detection using LiDAR data in its bird’s eye view projection are presented. Through a novel encoding, the use of architectures tailored to image detection is proposed to process the 3D information of point clouds in real time. Furthermore, the effectiveness of using this projection together with image features is analyzed. Finally, a method to mitigate the accuracy drop of LiDARbased detection networks when deployed in ad-hoc configurations is introduced. For this purpose, the simulation of virtual signals mimicking the specifications of the desired real device is used to generate new annotated datasets that can be used to train the models. The performance of the proposed methods is evaluated against other existing alternatives using reference benchmarks in the field of computer vision (KITTI and nuScenes) and through experiments in open traffic with an automated vehicle. The results obtained demonstrate the relevance of the presented work and its suitability for commercial use.La conducción autónoma está llamada a jugar un papel importante en los sistemas inteligentes de transporte de las próximas décadas. Las ventajas de su implementación a larga escala –disminución de accidentes, reducción del tiempo de trayecto, u optimización del consumo– han convertido su desarrollo en una prioridad para la academia y la industria. Sin embargo, todavía hay un largo camino por delante hasta alcanzar una automatización total, capaz de enfrentarse a cualquier escenario sin intervención humana. Para ello, aún se requieren avances en las tecnologías de control, navegación y, especialmente, percepción del entorno. Concretamente, la detección de otros usuarios de la carretera que puedan interferir en la trayectoria del vehículo es una pieza fundamental para conseguirlo, puesto que permite modelar el estado actual del tráfico y tomar decisiones en consecuencia. El objetivo de esta tesis es aportar soluciones a algunos de los principales retos de los sistemas de percepción embarcados, como la calibración extrínseca de los sensores, la detección de objetos, y su despliegue en plataformas reales. En primer lugar, se introduce un método para la obtención de la transformación relativa entre pares de sensores, eliminando el complejo ajuste manual de estos parámetros. El algoritmo hace uso de un patrón de calibración propio y da soporte a cámaras monoculares, estéreo, y LiDAR. En segundo lugar, se presentan diferentes modelos de aprendizaje profundo para la detección de objectos en 3D utilizando datos de escáneres LiDAR en su proyección en vista de pájaro. A través de una nueva codificación, se propone la utilización de arquitecturas de detección en imagen para procesar en tiempo real la información tridimensional de las nubes de puntos. Además, se analiza la efectividad del uso de esta proyección junto con características procedentes de imágenes. Por último, se introduce un método para mitigar la pérdida de precisión de las redes de detección basadas en LiDAR cuando son desplegadas en configuraciones ad-hoc. Para ello, se plantea la simulación de señales virtuales con las características del modelo real que se quiere utilizar, generando así nuevos conjuntos anotados para entrenar los modelos. El rendimiento de los métodos propuestos es evaluado frente a otras alternativas existentes haciendo uso de bases de datos de referencia en el campo de la visión por computador (KITTI y nuScenes), y mediante experimentos en tráfico abierto empleando un vehículo automatizado. Los resultados obtenidos demuestran la relevancia de los trabajos presentados y su viabilidad para un uso comercial.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Jesús García Herrero.- Secretario: Ignacio Parra Alonso.- Vocal: Gustavo Adolfo Peláez Coronad

Naturalistic Driver Intention and Path Prediction using Machine Learning

Autonomous vehicles are still yet to be available to the public. This is because there are a number of challenges that have not been overcome to ensure that autonomous vehicles can safely and efficiently drive on public roads. Accurate prediction of other vehicles is vital for safe driving, as interacting with other vehicles is unavoidable on public streets. This thesis explores reasons why this problem of scene understanding is still unsolved, and presents methods for driver intention and path prediction. The thesis focuses on intersections, as this is a very complex scenario in which to predict the actions of human drivers. There is very limited data available for intersection studies from the perspective of an autonomous vehicle. This thesis presents a very large dataset of over 23,000 vehicle trajectories, used to validate the algorithms presented in this thesis. This dataset was collected using a lidar based vehicle detection and tracking system onboard a vehicle. Analytics of this data is presented. To determine the intent of vehicle at an intersection, a method for manoeuvre classification through the use of recurrent neural networks is presented. This allows accurate predictions of which destination a vehicle will take at an unsignalised intersection, based on that vehicle's approach. The final contribution of this thesis presents a method for driver path prediction, based on recurrent neural networks. It produces a multi-modal prediction for the vehicle’s path with uncertainty assigned to each mode. The output modes are not hand labelled, but instead learned from the data. This results in there not being a fixed number of output modes. Whilst the application of this method is vehicle prediction, this method shows significant promise to be used in other areas of robotics

Real-time 3D object detection and SLAM fusion in a low-cost LiDAR test vehicle setup

Recently released research about deep learning applications related to perception for autonomous driving focuses heavily on the usage of LiDAR point cloud data as input for the neural networks, highlighting the importance of LiDAR technology in the field of Autonomous Driving (AD). In this sense, a great percentage of the vehicle platforms used to create the datasets released for the development of these neural networks, as well as some AD commercial solutions available on the market, heavily invest in an array of sensors, including a large number of sensors as well as several sensor modalities. However, these costs create a barrier to entry for low-cost solutions for the performance of critical perception tasks such as Object Detection and SLAM. This paper explores current vehicle platforms and proposes a low-cost, LiDAR-based test vehicle platform capable of running critical perception tasks (Object Detection and SLAM) in real time. Additionally, we propose the creation of a deep learning-based inference model for Object Detection deployed in a resource-constrained device, as well as a graph-based SLAM implementation, providing important considerations, explored while taking into account the real-time processing requirement and presenting relevant results demonstrating the usability of the developed work in the context of the proposed low-cost platform

LiDAR-Based Object Tracking and Shape Estimation

Umfeldwahrnehmung stellt eine Grundvoraussetzung für den sicheren und komfortablen Betrieb automatisierter Fahrzeuge dar. Insbesondere bewegte Verkehrsteilnehmer in der unmittelbaren Fahrzeugumgebung haben dabei große Auswirkungen auf die Wahl einer angemessenen Fahrstrategie. Dies macht ein System zur Objektwahrnehmung notwendig, welches eine robuste und präzise Zustandsschätzung der Fremdfahrzeugbewegung und -geometrie zur Verfügung stellt. Im Kontext des automatisierten Fahrens hat sich das Box-Geometriemodell über die Zeit als Quasistandard durchgesetzt. Allerdings stellt die Box aufgrund der ständig steigenden Anforderungen an Wahrnehmungssysteme inzwischen häufig eine unerwünscht grobe Approximation der tatsächlichen Geometrie anderer Verkehrsteilnehmer dar. Dies motiviert einen Übergang zu genaueren Formrepräsentationen. In der vorliegenden Arbeit wird daher ein probabilistisches Verfahren zur gleichzeitigen Schätzung von starrer Objektform und -bewegung mittels Messdaten eines LiDAR-Sensors vorgestellt. Der Vergleich dreier Freiform-Geometriemodelle mit verschiedenen Detaillierungsgraden (Polygonzug, Dreiecksnetz und Surfel Map) gegenüber dem einfachen Boxmodell zeigt, dass die Reduktion von Modellierungsfehlern in der Objektgeometrie eine robustere und präzisere Parameterschätzung von Objektzuständen ermöglicht. Darüber hinaus können automatisierte Fahrfunktionen, wie beispielsweise ein Park- oder Ausweichassistent, von einem genaueren Wissen über die Fremdobjektform profitieren. Es existieren zwei Einflussgrößen, welche die Auswahl einer angemessenen Formrepräsentation maßgeblich beeinflussen sollten: Beobachtbarkeit (Welchen Detaillierungsgrad lässt die Sensorspezifikation theoretisch zu?) und Modell-Adäquatheit (Wie gut bildet das gegebene Modell die tatsächlichen Beobachtungen ab?). Auf Basis dieser Einflussgrößen wird in der vorliegenden Arbeit eine Strategie zur Modellauswahl vorgestellt, die zur Laufzeit adaptiv das am besten geeignete Formmodell bestimmt. Während die Mehrzahl der Algorithmen zur LiDAR-basierten Objektverfolgung ausschließlich auf Punktmessungen zurückgreift, werden in der vorliegenden Arbeit zwei weitere Arten von Messungen vorgeschlagen: Information über den vermessenen Freiraum wird verwendet, um über Bereiche zu schlussfolgern, welche nicht von Objektgeometrie belegt sein können. Des Weiteren werden LiDAR-Intensitäten einbezogen, um markante Merkmale wie Nummernschilder und Retroreflektoren zu detektieren und über die Zeit zu verfolgen. Eine ausführliche Auswertung auf über 1,5 Stunden von aufgezeichneten Fremdfahrzeugtrajektorien im urbanen Bereich und auf der Autobahn zeigen, dass eine präzise Modellierung der Objektoberfläche die Bewegungsschätzung um bis zu 30%-40% verbessern kann. Darüber hinaus wird gezeigt, dass die vorgestellten Methoden konsistente und hochpräzise Rekonstruktionen von Objektgeometrien generieren können, welche die häufig signifikante Überapproximation durch das einfache Boxmodell vermeiden

Contextual information aided target tracking and path planning for autonomous ground vehicles

Recently, autonomous vehicles have received worldwide attentions from academic research, automotive industry and the general public. In order to achieve a higher level of automation, one of the most fundamental requirements of autonomous vehicles is the capability to respond to internal and external changes in a safe, timely and appropriate manner. Situational awareness and decision making are two crucial enabling technologies for safe operation of autonomous vehicles. This thesis presents a solution for improving the automation level of autonomous vehicles in both situational awareness and decision making aspects by utilising additional domain knowledge such as constraints and influence on a moving object caused by environment and interaction between different moving objects. This includes two specific sub-systems, model based target tracking in environmental perception module and motion planning in path planning module. In the first part, a rigorous Bayesian framework is developed for pooling road constraint information and sensor measurement data of a ground vehicle to provide better situational awareness. Consequently, a new multiple targets tracking (MTT) strategy is proposed for solving target tracking problems with nonlinear dynamic systems and additional state constraints. Besides road constraint information, a vehicle movement is generally affected by its surrounding environment known as interaction information. A novel dynamic modelling approach is then proposed by considering the interaction information as virtual force which is constructed by involving the target state, desired dynamics and interaction information. The proposed modelling approach is then accommodated in the proposed MTT strategy for incorporating different types of domain knowledge in a comprehensive manner. In the second part, a new path planning strategy for autonomous vehicles operating in partially known dynamic environment is suggested. The proposed MTT technique is utilized to provide accurate on-board tracking information with associated level of uncertainty. Based on the tracking information, a path planning strategy is developed to generate collision free paths by not only predicting the future states of the moving objects but also taking into account the propagation of the associated estimation uncertainty within a given horizon. To cope with a dynamic and uncertain road environment, the strategy is implemented in a receding horizon fashion

Data fusion architecture for intelligent vehicles

Traffic accidents are an important socio-economic problem. Every year, the cost in human lives and the economic consequences are inestimable. During the latest years, efforts to reduce or mitigate this problem have lead to a reduction in casualties. But, the death toll in road accidents is still a problem, which means that there is still much work to be done. Recent advances in information technology have lead to more complex applications, which have the ability to help or even substitute the driver in case of hazardous situations, allowing more secure and efficient driving. But these complex systems require more trustable and accurate sensing technology that allows detecting and identifying the surrounding environment as well as identifying the different objects and users. However, the sensing technology available nowadays is insufficient itself, and thus combining the different available technologies is mandatory in order to fulfill the exigent requirements of safety road applications. In this way, the limitations of every system are overcome. More dependable and reliable information can be thus obtained. These kinds of applications are called Data Fusion (DF) applications. The present document tries to provide a solution for the Data Fusion problem in the Intelligent Transport System (ITS) field by providing a set of techniques and algorithms that allow the combination of information from different sensors. By combining these sensors the basic performances of the classical approaches in ITS can be enhanced, satisfying the demands of safety applications. The works presented are related with two researching fields. Intelligent Transport System is the researching field where this thesis was established. ITS tries to use the recent advances in Information Technology to increase the security and efficiency of the transport systems. Data Fusion techniques, on the other hand, try to give solution to the process related with the combination of information from different sources, enhancing the basic capacities of the systems and adding trustability to the inferences. This work attempts to use the Data Fusion algorithms and techniques to provide solution to classic ITS applications. The sensors used in the present application include a laser scanner and computer vision. First is a well known sensor, widely used, and during more recent years have started to be applied in different ITS applications, showing advanced performance mainly related to its trustability. Second is a recent sensor in automotive applications widely used in all recent ITS advances in the last decade. Thanks to computer vision road security applications (e.g. traffic sign detection, driver monitoring, lane detection, pedestrian detection, etc.) advancements are becoming possible. The present thesis tries to solve the environment reconstruction problem, identifying users of the roads (i.e. pedestrians and vehicles) by the use of Data Fusion techniques. The solution delivers a complete level based solution to the Data Fusion problem. It provides different tools for detecting as well as estimates the degree of danger that involve any detection. Presented algorithms represents a step forward in the ITS world, providing novel Data Fusion based algorithms that allow the detection and estimation of movement of pedestrians and vehicles in a robust and trustable way. To perform such a demanding task other information sources were needed: GPS, inertial systems and context information. Finally, it is important to remark that in the frame of the present thesis, the lack of detection and identification techniques based in radar laser resulted in the need to research and provide more innovative approaches, based in the use of laser scanner, able to detect and identify the different actors involved in the road environment. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Los accidentes de tráfico son un grave problema social y económico, cada año el coste tanto en vidas humanas como económico es incontable, por lo que cualquier acción que conlleve la reducción o eliminación de esta lacra es importante. Durante los últimos años se han hecho avances para mitigar el número de accidentes y reducir sus consecuencias. Estos esfuerzos han dado sus frutos, reduciendo el número de accidentes y sus víctimas. Sin embargo el número de heridos y muertos en accidentes de este tipo es aún muy alto, por lo que no hay que rebajar los esfuerzos encaminados a hacer desaparecer tan importante problema. Los recientes avances en tecnologías de la información han permitido la creación de sistemas de ayuda a la conducción cada vez más complejos, capaces de ayudar e incluso sustituir al conductor, permitiendo una conducción más segura y eficiente. Pero estos complejos sistemas requieren de los sensores más fiables, capaces de permitir reconstruir el entorno, identificar los distintos objetos que se encuentran en él e identificar los potenciales peligros. Los sensores disponibles en la actualidad han demostrado ser insuficientes para tan ardua tarea, debido a los enormes requerimientos que conlleva una aplicación de seguridad en carretera. Por lo tanto, combinar los diferentes sensores disponibles se antoja necesario para llegar a los niveles de eficiencia y confianza que requieren este tipo de aplicaciones. De esta forma, las limitaciones de cada sensor pueden ser superadas, gracias al uso combinado de los diferentes sensores, cada uno de ellos proporcionando información que complementa la obtenida por otros sistemas. Este tipo de aplicaciones se denomina aplicaciones de Fusión Sensorial. El presente trabajo busca aportar soluciones en el entorno de los vehículos inteligentes, mediante técnicas de fusión sensorial, a clásicos problemas relacionados con la seguridad vial. Se buscará combinar diferentes sensores y otras fuentes de información, para obtener un sistema fiable, capaz de satisfacer las exigentes demandas de este tipo de aplicaciones. Los estudios realizados y algoritmos propuestos están enmarcados en dos campos de investigación bien conocidos y populares. Los Sistemas Inteligentes de Transporte (ITS- por sus siglas en ingles- Intelligent Transportation Systems), marco en el que se centra la presente tesis, que engloba las diferentes tecnologías que durante los últimos años han permitido dotar a los sistemas de transporte de mejoras que aumentan la seguridad y eficiencia de los sistemas de transporte tradicionales, gracias a las novedades en el campo de las tecnologías de la información. Por otro lado las técnicas de Fusión Sensorial (DF -por sus siglas en ingles- Data Fusión) engloban las diferentes técnicas y procesos necesarios para combinar diferentes fuentes de información, permitiendo mejorar las prestaciones y dando fiabilidad a los sistemas finales. La presente tesis buscará el empleo de las técnicas de Fusión Sensorial para dar solución a problemas relacionados con Sistemas Inteligentes de Transporte. Los sensores escogidos para esta aplicación son un escáner láser y visión por computador. El primero es un sensor ampliamente conocido, que durante los últimos años ha comenzado a emplearse en el mundo de los ITS con unos excelentes resultados. El segundo de este conjunto de sensores es uno de los sistemas más empleados durante los últimos años, para dotar de cada vez más complejos y versátiles aplicaciones en el mundo de los ITS. Gracias a la visión por computador, aplicaciones tan necesarias para la seguridad como detección de señales de tráfico, líneas de la carreta, peatones, etcétera, que hace unos años parecía ciencia ficción, están cada vez más cerca. La aplicación que se presenta pretende dar solución al problema de reconstrucción de entornos viales, identificando a los principales usuarios de la carretera (vehículos y peatones) mediante técnicas de Fusión Sensorial. La solución implementada busca dar una completa solución a todos los niveles del proceso de fusión sensorial, proveyendo de las diferentes herramientas, no solo para detectar los otros usuarios, sino para dar una estimación del peligro que cada una de estas detecciones implica. Para lograr este propósito, además de los sensores ya comentados han sido necesarias otras fuentes de información, como sensores GPS, inerciales e información contextual. Los algoritmos presentados pretenden ser un importante paso adelante en el mundo de los Sistemas Inteligentes de Transporte, proporcionando novedosos algoritmos basados en tecnologías de Fusión Sensorial que permitirán detectar y estimar el movimiento de los peatones y vehículos de forma fiable y robusta. Finalmente hay que remarcar que en el marco de la presente tesis, la falta de sistemas de detección e identificación de obstáculos basados en radar láser provocó la necesidad de implementar novedosos algoritmos que detectasen e identificasen, en la medida de lo posible y pese a las limitaciones de la tecnología, los diferentes obstáculos que se pueden encontrar en la carretera basándose en este sensor

Cooperative perception for driving applications

An automated vehicle needs to understand its driving environment to operate safely and reliably. This function is performed within the vehicle's perception system, where data from on-board sensors is processed by multiple perception algorithms, including 3D object detection, semantic segmentation and object tracking. To take advantage of different sensor modalities, multiple perception methods fusing the data from on-board cameras and lidars have been devised. However, sensing exclusively from a single vehicle is inherently prone to occlusions and a limited field-of-view that indiscriminately affects all sensor modalities. Alternatively, cooperative perception incorporates sensor observations from multiple view points distributed throughout the driving environment. This research investigates if and how cooperative perception is capable of improving the detection of objects in driving environments using data from multiple, spatially diverse sensors. Over the course of this thesis, four studies are conducted considering different aspects of cooperative perception. The first study considers the various impacts of occlusions and sensor noise on the classification of objects in images and investigates how to fuse data from multiple images. This study serves as a proof-of-concept to validate the core idea of cooperative perception and presents quantitative results on how well cooperative perception can mitigate such impairments. The second study generalises the problem to 3D object detection using infrastructure sensors capable of providing depth information and investigates different sensor fusion approaches for such sensors. Three sensor fusion approaches are devised and evaluated in terms of object detection performance, communication bandwidth and inference time. This study also investigates the impact of the number of sensors in the performance of object detection. The results show that the proposed cooperative 3D object detection method achieves more than thrice the number of correct detections compared to single sensor baselines, while also reducing the number of false positive detections. Next, the problem of optimising the pose of fixed infrastructure sensors in cluttered driving environments is considered. Two novel sensor pose optimisation methods are proposed, one using gradient-based optimisation and one using integer programming techniques, to maximise the visibility of objects. Both use a novel visibility model, based on a rendering engine, capable of determining occlusions between objects. The results suggest that both methods have the potential to guide the cost effective deployment of sensor networks in cooperative perception applications. Finally, the last study considers the problem of estimating the relative pose between non-static sensors relying on sensor data alone. To that end, a novel and computationally efficient point cloud registration method is proposed using a bespoke feature encoder and attention network. Extensive results show that the proposed method is capable of operating in real-time and is more robust for point clouds with low _eld-of-view overlap compared to existing methods

Implementing and Tuning an Autonomous Racing Car Testbed

Achieving safe autonomous driving is far from a vision at present days, with many examples like Uber, Google and the most famous of all Tesla, as they successfully deployed self driving cars around the world. Researchers and engineers have been putting tremendous efforts and will continue to do so in the following years into developing safe and precise control algorithms and technologies that will be included in future self driving cars. Besides these well known autonomous car deployments, some focus has also been put into autonomous racing competitions, for example the Roborace. The fact is that although significant progress that has been made, testing on real size cars in real environments requires immense financial support, making it impossible for many research groups to enter the game. Consequently, interesting alternatives appeared, such as the F1 Tenth, which challenges students, researchers and engineers to embrace in a low cost autonomous racing competition while developing control algorithms, that rely on sensors and strategies used in real life applications. This thesis focus on the comparison of different control algorithms and their effectiveness, that are present in a racing aspect of the F1 Tenth competition. In this thesis, efforts were put into developing a robotic autonomous car, relying on Robot Operative System, ROS, that not only meet the specifications from the F1 Tenth rules, but also allowed to establish a testbed for different future autonomous driving research.Obter uma condução autónoma segura está longe de uma visão dos dias de hoje, com exemplos como a Uber, Google e o mais famoso deles todos, a Tesla, que já foram globalmente introduzidos com sucesso. Investigadores e engenheiros têm colocado um empenho tremendo e vão continuar a fazê-lo nos próximos anos, a desenvolver algoritmos de controlo precisos e seguros, bem como tecnologias que serão colocados nos carros autónomos do futuro. Para além destes casos de sucesso bem conhecidos, algum foco tem sido colocado em competições de corridas de carros autónomos, como por exemplo o Roborace. O facto ´e que apesar do progresso significante que tem sido feito, fazer testes em carros reais em cenários verdadeiros, requer grande investimento financeiro, tornando impossível para muitos grupos de investigação investir na área. Consequentemente, apareceram alternativas relevantes, tal como o F1 Tenth, que desafia estudantes, investigadores e engenheiros a aderir a uma competição de baixos custos de corridas autónomas, enquanto desenvolvem algoritmos de controlo, que dependem de sensores e estratégias usadas em aplicações reais. Esta tese foca-se na comparação de diferentes algoritmos de controlo e na eficácia dos mesmos, que estão presentes num cenário de corrida da competição do F1 Tenth. Nesta tese, foram colocados muitos esforços para o desenvolvimento de um carro autónomo robótico, baseado em Robot Operative System, ROS, que não só vai de encontro `as especificações do F1 Tenth, mas que também permita estabelecer uma plataforma para futuras investigações de condução autónoma