Parametric kernels for structured data analysis

textStructured representation of input physical patterns as a set of local features has been useful for a veriety of robotics and human computer interaction (HCI) applications. It enables a stable understanding of the variable inputs. However, this representation does not fit the conventional machine learning algorithms and distance metrics because they assume vector inputs. To learn from input patterns with variable structure is thus challenging. To address this problem, I propose a general and systematic method to design distance metrics between structured inputs that can be used in conventional learning algorithms. Based on the observation of the stability in the geometric distributions of local features over the physical patterns across similar inputs, this is done combining the local similarities and the conformity of the geometric relationship between local features. The produced distance metrics, called “parametric kernels”, are positive semi-definite and require almost linear time to compute. To demonstrate the general applicability and the efficacy of this approach, I designed and applied parametric kernels to handwritten character recognition, on-line face recognition, and object detection from laser range finder sensor data. Parametric kernels achieve recognition rates competitive to state-of-the-art approaches in these tasks.Computer Science

Visual Place Recognition for Autonomous Robots

Autonomous robotics has been the subject of great interest within the research community over the past few decades. Its applications are wide-spread, ranging from health-care to manufacturing, goods transportation to home deliveries, site-maintenance to construction, planetary explorations to rescue operations and many others, including but not limited to agriculture, defence, commerce, leisure and extreme environments. At the core of robot autonomy lies the problem of localisation, i.e, knowing where it is and within the robotics community, this problem is termed as place recognition. Place recognition using only visual input is termed as Visual Place Recognition (VPR) and refers to the ability of an autonomous system to recall a previously visited place using only visual input, under changing viewpoint, illumination and seasonal conditions, and given computational and storage constraints. This thesis is a collection of 4 inter-linked, mutually-relevant but branching-out topics within VPR: 1) What makes a place/image worthy for VPR?, 2) How to define a state-of-the-art in VPR?, 3) Do VPR techniques designed for ground-based platforms extend to aerial platforms? and 4) Can a handcrafted VPR technique outperform deep-learning-based VPR techniques? Each of these questions is a dedicated, peer-reviewed chapter in this thesis and the author attempts to answer these questions to the best of his abilities. The worthiness of a place essentially refers to the salience and distinctiveness of the content in the image of this place. This salience is modelled as a framework, namely memorable-maps, comprising of 3 conjoint criteria: a) Human-memorability of an image, 2) Staticity and 3) Information content. Because a large number of VPR techniques have been proposed over the past 10-15 years, and due to the variation of employed VPR datasets and metrics for evaluation, the correct state-of-the-art remains ambiguous. The author levels this playing field by deploying 10 contemporary techniques on a common platform and use the most challenging VPR datasets to provide a holistic performance comparison. This platform is then extended to aerial place recognition datasets to answer the 3rd question above. Finally, the author designs a novel, handcrafted, compute-efficient and training-free VPR technique that outperforms state-of-the-art VPR techniques on 5 different VPR datasets

Robot Perception of Static and Dynamic Objects with an Autonomous Floor Scrubber

This paper presents the perception system of a new professional cleaning robot for large public places. The proposed system is based on multiple sensors including 3D and 2D lidar, two RGB-D cameras and a stereo camera. The two lidars together with an RGB-D camera are used for dynamic object (human) detection and tracking, while the second RGB-D and stereo camera are used for detection of static objects (dirt and ground objects). A learning and reasoning module for spatial-temporal representation of the environment based on the perception pipeline is also introduced. Furthermore, a new dataset collected with the robot in several public places, including a supermarket, a warehouse and an airport, is released.Baseline results on this dataset for further research and comparison are provided. The proposed system has been fully implemented into the Robot Operating System (ROS) with high modularity, also publicly available to the community

Omnidirectional Stereo Vision Study from Vertical and Horizontal Stereo Configuration

In stereo vision, an omnidirectional camera has high distortion compared to a standard camera, so the camera calibration is very decisive in its stereo matching. In this study, we will perform stereo matching for an omnidirectional camera with vertical and horizontal configuration so that the result of the image's depth has a 360-degree field of view by transforming the image using a calibration-based method. The result is that by using a vertical camera configuration, the image can be stereo matched directly, but by configuring a horizontal image, it is necessary to carry out a different stereo-matching process in each direction. Stereo matching with the semi-global matching method has better image results than block matching with more image objects detectable by the semi-global block matching method with a maximum disparity value of 32 pixels and with a window size of 21 pixels

Automatic visual detection of human behavior: a review from 2000 to 2014

Due to advances in information technology (e.g., digital video cameras, ubiquitous sensors), the automatic detection of human behaviors from video is a very recent research topic. In this paper, we perform a systematic and recent literature review on this topic, from 2000 to 2014, covering a selection of 193 papers that were searched from six major scientific publishers. The selected papers were classified into three main subjects: detection techniques, datasets and applications. The detection techniques were divided into four categories (initialization, tracking, pose estimation and recognition). The list of datasets includes eight examples (e.g., Hollywood action). Finally, several application areas were identified, including human detection, abnormal activity detection, action recognition, player modeling and pedestrian detection. Our analysis provides a road map to guide future research for designing automatic visual human behavior detection systems.This work is funded by the Portuguese Foundation for Science and Technology (FCT - Fundacao para a Ciencia e a Tecnologia) under research Grant SFRH/BD/84939/2012

Locomotion system for ground mobile robots in uneven and unstructured environments

One of the technology domains with the greatest growth rates nowadays is service robots. The extensive use of ground mobile robots in environments that are unstructured or structured for humans is a promising challenge for the coming years, even though Automated Guided Vehicles (AGV) moving on flat and compact grounds are already commercially available and widely utilized to move components and products inside indoor industrial buildings. Agriculture, planetary exploration, military operations, demining, intervention in case of terrorist attacks, surveillance, and reconnaissance in hazardous conditions are important application domains. Due to the fact that it integrates the disciplines of locomotion, vision, cognition, and navigation, the design of a ground mobile robot is extremely interdisciplinary. In terms of mechanics, ground mobile robots, with the exception of those designed for particular surroundings and surfaces (such as slithering or sticky robots), can move on wheels (W), legs (L), tracks (T), or hybrids of these concepts (LW, LT, WT, LWT). In terms of maximum speed, obstacle crossing ability, step/stair climbing ability, slope climbing ability, walking capability on soft terrain, walking capability on uneven terrain, energy efficiency, mechanical complexity, control complexity, and technology readiness, a systematic comparison of these locomotion systems is provided in [1]. Based on the above-mentioned classification, in this thesis, we first introduce a small-scale hybrid locomotion robot for surveillance and inspection, WheTLHLoc, with two tracks, two revolving legs, two active wheels, and two passive omni wheels. The robot can move in several different ways, including using wheels on the flat, compact ground,[1] tracks on soft, yielding terrain, and a combination of tracks, legs, and wheels to navigate obstacles. In particular, static stability and non-slipping characteristics are considered while analyzing the process of climbing steps and stairs. The experimental test on the first prototype has proven the planned climbing maneuver’s efficacy and the WheTLHLoc robot's operational flexibility. Later we present another development of WheTLHLoc and introduce WheTLHLoc 2.0 with newly designed legs, enabling the robot to deal with bigger obstacles. Subsequently, a single-track bio-inspired ground mobile robot's conceptual and embodiment designs are presented. This robot is called SnakeTrack. It is designed for surveillance and inspection activities in unstructured environments with constrained areas. The vertebral column has two end modules and a variable number of vertebrae linked by compliant joints, and the surrounding track is its essential component. Four motors drive the robot: two control the track motion and two regulate the lateral flexion of the vertebral column for steering. The compliant joints enable limited passive torsion and retroflection of the vertebral column, which the robot can use to adapt to uneven terrain and increase traction. Eventually, the new version of SnakeTrack, called 'Porcospino', is introduced with the aim of allowing the robot to move in a wider variety of terrains. The novelty of this thesis lies in the development and presentation of three novel designs of small-scale mobile robots for surveillance and inspection in unstructured environments, and they employ hybrid locomotion systems that allow them to traverse a variety of terrains, including soft, yielding terrain and high obstacles. This thesis contributes to the field of mobile robotics by introducing new design concepts for hybrid locomotion systems that enable robots to navigate challenging environments. The robots presented in this thesis employ modular designs that allow their lengths to be adapted to suit specific tasks, and they are capable of restoring their correct position after falling over, making them highly adaptable and versatile. Furthermore, this thesis presents a detailed analysis of the robots' capabilities, including their step-climbing and motion planning abilities. In this thesis we also discuss possible refinements for the robots' designs to improve their performance and reliability. Overall, this thesis's contributions lie in the design and development of innovative mobile robots that address the challenges of surveillance and inspection in unstructured environments, and the analysis and evaluation of these robots' capabilities. The research presented in this thesis provides a foundation for further work in this field, and it may be of interest to researchers and practitioners in the areas of robotics, automation, and inspection. As a general note, the first robot, WheTLHLoc, is a hybrid locomotion robot capable of combining tracked locomotion on soft terrains, wheeled locomotion on flat and compact grounds, and high obstacle crossing capability. The second robot, SnakeTrack, is a small-size mono-track robot with a modular structure composed of a vertebral column and a single peripherical track revolving around it. The third robot, Porcospino, is an evolution of SnakeTrack and includes flexible spines on the track modules for improved traction on uneven but firm terrains, and refinements of the shape of the track guidance system. This thesis provides detailed descriptions of the design and prototyping of these robots and presents analytical and experimental results to verify their capabilities

Towards Intelligent Playful Environments for Animals based on Natural User Interfaces

Tesis por compendioEl estudio de la interacción de los animales con la tecnología y el desarrollo de sistemas tecnológicos centrados en el animal está ganando cada vez más atención desde la aparición del área de Animal Computer Interaction (ACI). ACI persigue mejorar el bienestar de los animales en diferentes entornos a través del desarrollo de tecnología adecuada para ellos siguiendo un enfoque centrado en el animal. Entre las líneas de investigación que ACI está explorando, ha habido bastante interés en la interacción de los animales con la tecnología basada en el juego. Las actividades de juego tecnológicas tienen el potencial de proveer estimulación mental y física a los animales en diferentes contextos, pudiendo ayudar a mejorar su bienestar. Mientras nos embarcamos en la era de la Internet de las Cosas, las actividades de juego tecnológicas actuales para animales todavía no han explorado el desarrollo de soluciones pervasivas que podrían proveerles de más adaptación a sus preferencias a la vez que ofrecer estímulos tecnológicos más variados. En su lugar, estas actividades están normalmente basadas en interacciones digitales en lugar de explorar dispositivos tangibles o aumentar las interacciones con otro tipo de estímulos. Además, estas actividades de juego están ya predefinidas y no cambian con el tiempo, y requieren que un humano provea el dispositivo o la tecnología al animal. Si los humanos pudiesen centrarse más en su participación como jugadores de un sistema interactivo para animales en lugar de estar pendientes de sujetar un dispositivo para el animal o de mantener el sistema ejecutándose, esto podría ayudar a crear lazos más fuertes entre especies y promover mejores relaciones con los animales. Asimismo, la estimulación mental y física de los animales son aspectos importantes que podrían fomentarse si los sistemas de juego diseñados para ellos pudieran ofrecer un variado rango de respuestas, adaptarse a los comportamientos del animal y evitar que se acostumbre al sistema y pierda el interés. Por tanto, esta tesis propone el diseño y desarrollo de entornos tecnológicos de juego basados en Interfaces Naturales de Usuario que puedan adaptarse y reaccionar a las interacciones naturales de los animales. Estos entornos pervasivos permitirían a los animales jugar por si mismos o con una persona, ofreciendo actividades de juego más dinámicas y atractivas capaces de adaptarse con el tiempo.L'estudi de la interacció dels animals amb la tecnologia i el desenvolupament de sistemes tecnològics centrats en l'animal està guanyant cada vegada més atenció des de l'aparició de l'àrea d'Animal Computer Interaction (ACI) . ACI persegueix millorar el benestar dels animals en diferents entorns a través del desenvolupament de tecnologia adequada per a ells amb un enfocament centrat en l'animal. Entre totes les línies d'investigació que ACI està explorant, hi ha hagut prou interès en la interacció dels animals amb la tecnologia basada en el joc. Les activitats de joc tecnològiques tenen el potencial de proveir estimulació mental i física als animals en diferents contextos, podent ajudar a millorar el seu benestar. Mentre ens embarquem en l'era de la Internet de les Coses, les activitats de joc tecnològiques actuals per a animals encara no han explorat el desenvolupament de solucions pervasives que podrien proveir-los de més adaptació a les seues preferències al mateix temps que oferir estímuls tecnològics més variats. En el seu lloc, estes activitats estan normalment basades en interaccions digitals en compte d'explorar dispositius tangibles o augmentar les interaccions amb estímuls de diferent tipus. A més, aquestes activitats de joc estan ja predefinides i no canvien amb el temps, mentre requereixen que un humà proveïsca el dispositiu o la tecnologia a l'animal. Si els humans pogueren centrar-se més en la seua participació com a jugadors actius d'un sistema interactiu per a animals en compte d'estar pendents de subjectar un dispositiu per a l'animal o de mantenir el sistema executant-se, açò podria ajudar a crear llaços més forts entre espècies i promoure millors relacions amb els animals. Així mateix, l'estimulació mental i física dels animals són aspectes importants que podrien fomentar-se si els sistemes de joc dissenyats per a ells pogueren oferir un rang variat de respostes, adaptar-se als comportaments de l'animal i evitar que aquest s'acostume al sistema i perda l'interès. Per tant, esta tesi proposa el disseny i desenvolupament d'entorns tecnològics de joc basats en Interfícies Naturals d'Usuari que puguen adaptar-se i reaccionar a les interaccions naturals dels animals. Aquestos escenaris pervasius podrien permetre als animals jugar per si mateixos o amb una persona, oferint activitats de joc més dinàmiques i atractives que siguen capaces d'adaptar-se amb el temps.The study of animals' interactions with technology and the development of animal-centered technological systems is gaining attention since the emergence of the research area of Animal Computer Interaction (ACI). ACI aims to improve animals' welfare and wellbeing in several scenarios by developing suitable technology for the animal following an animal-centered approach. Among all the research lines ACI is exploring, there has been significant interest in animals' playful interactions with technology. Technologically mediated playful activities have the potential to provide mental and physical stimulation for animals in different environmental contexts, which could in turn help to improve their wellbeing. As we embark in the era of the Internet of Things, current technological playful activities for animals have not yet explored the development of pervasive solutions that could provide animals with more adaptation to their preferences as well as offering varied technological stimuli. Instead, playful technology for animals is usually based on digital interactions rather than exploring tangible devices or augmenting the interactions with different stimuli. In addition, these playful activities are already predefined and do not change over time, while they require that a human has to be the one providing the device or technology to the animal. If humans could focus more on their participation as active players of an interactive system aimed for animals instead of being concerned about holding a device for the animal or keep the system running, this might help to create stronger bonds between species and foster better relationships with animals. Moreover, animals' mental and physical stimulation are important aspects that could be fostered if the playful systems designed for animals could offer a varied range of outputs, be tailored to the animal's behaviors and prevented the animal to get used to the system and lose interest. Therefore, this thesis proposes the design and development of technological playful environments based on Natural User Interfaces that could adapt and react to the animals' natural interactions. These pervasive scenarios would allow animals to play by themselves or with a human, providing more engaging and dynamic playful activities that are capable of adapting over time.Pons Tomás, P. (2018). Towards Intelligent Playful Environments for Animals based on Natural User Interfaces [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/113075TESISCompendi