David Valiente

• PhD
• Professor (Associate) at Miguel Hernández University of Elche

In autonomous navigation systems, the solution of the place recognition problem is crucial for their safe functioning. But this is not a trivial solution, since it must be accurate regardless of any changes in the scene, such as seasonal changes and different weather conditions, and it must be generalizable to other environments. This paper present...

The location of a robot is a key aspect in the field of mobile robotics. This problem is particularly complex when the initial pose of the robot is unknown. In order to find a solution, it is necessary to perform a global localization. In this paper, we propose a method that addresses this problem using a coarse-to-fine solution. The coarse localiz...

Ground segmentation in LiDAR point clouds is a foundational capability for autonomous systems, enabling safe navigation in applications ranging from urban self-driving vehicles to planetary exploration rovers. Reliably distinguishing traversable surfaces in geometrically irregular or sensor-sparse environments remains a critical challenge. This pap...

This paper presents a comparison of different image fusion methods for matching visible-spectrum images with thermal-spectrum (far-infrared) images, aimed at enhancing person detection using convolutional neural networks (CNNs). While object detection with RGB images is a well-developed area, it is still greatly limited by lighting conditions. This...

El presente póster tiene como objetivo mostrar el diseño y desarrollo de una interfaz gráfica para monitorización, teleoperación y control de un robot móvil, la cual permite ver los datos de los sensores del robot además de comandarlo manualmente y realizar una planificación y seguimiento de trayectorias.

Organic solar cells (OSCs), especially those employing bulk heterojunction architecture, present a promising avenue in renewable energy technology. These devices utilize organic materials and can be doped by solvents such as dimethylformamide (DMF), tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO). Solvent doping (DMF, THF, and DMSO) is observe...

El presente artı́culo tiene como objetivo mostrar el diseño y desarrollo de una interfaz gráfica para monitorización, teleoperación y control de un robot móvil, la cual permite ver los datos de los sensores del robot además de comandarlo manualmente y realizar una planificación y seguimiento de trayectorias. La interfaz ha sido implementada sobre F...

Los robots móviles tienen la capacidad de desplazarse de manera autónoma, para ello es necesario conocer su posición. Esta estimación puede ser obtenida a partir de diversos sensores. Uno de los sensores más comúnmente utilizados son los sistemas de visión por la gran cantidad de información que son capaces de capturar. Para extraer la información...

This paper presents TE-NeXt, a novel and efficient architecture for Traversability Estimation (TE) from sparse LiDAR point clouds based on a residual convolution block. TE-NeXt block fuses notions of current trends such as attention mechanisms and 3D sparse convolutions. TE-NeXt aims to demonstrate high capacity for generalisation in a variety of u...

This paper presents a review of different image fusion methods for the combination of visible spectrum images with thermal spectrum (far-infrared) images, aimed to enhance people detection by means of Convolutional Neural Networks (CNNs). While image detection with RGB images is a well-developed area, it still heavily relies on and is greatly limit...

Full spherical views provide advantages in many applications that use visual information. Dual back-to-back fisheye cameras are receiving much attention to obtain this type of view. However, obtaining a high-quality full spherical view is very challenging. In this paper, we propose a correction step that models the relation between the pixels of th...

The energy sector is a major contributor to global greenhouse gas emissions, necessitating a transition to renewable energy sources. The photovoltaic industry plays a crucial role in this transition by harnessing solar energy, a clean and abundant resource. However, the high cost of solar panels remains a challenge. Organic solar cells (OSCs) offer...

Los sistemas de visión conformados por dos lentes fisheye posicionadas de forma que cubran un campo de visión de 360° presentan grandes ventajas, como la posibilidad de obtener una vista 360 de alta calidad, que puede ser usada en otras tareas de alto nivel. Haciendo uso de una cámara comercial de este tipo, el principal objetivo del trabajo consis...

Beyond 5G networks, and for short distance but high-speed communication systems, there is an incipient growing interest in visible light communications (VLC). Furthermore, it is an interesting alternative within the framework of the Internet of Things (IoT). However, there is a problem on the part of the receiver in these systems, motivated by the...

Feature matching is a key technique for a wide variety of computer vision and image processing applications such as visual localization. It permits finding correspondences of significant points within the environment that eventually determine the localization of a mobile agent. In this context, this work evaluates an Adaptive Probability-Oriented F...

Un robot móvil debe ser capaz de localizarse en el entorno en el que se encuentra para navegar de forma autónoma. Para tal fin, en este trabajo se utiliza un método denominado Adaptive Probability-Oriented Feature Matching (APOFM). Este algoritmo consiste en obtener la pose relativa a partir de información visual de un par de imágenes, como un algo...

University education approaches related to the field of science, technology, engineering and mathematics (STEM), have generally particularized on teaching activity and learning programs which are commonly understood as reoriented lessons that fuse theoretic concepts interweaved with practical activities. In this context, team work has been widely a...

In this study, poly(9-vinylcarbazole) (PVK)-based LEDs doped with reduced graphene oxide (rGO) and cadmium sulphide (CdS) nanocrystals were fabricated by spin-coating. The hybrid LED structure was a layer sequence of glass/indium tin oxide (ITO)/PEDOT:PSS|rGO/PVK/Al. rGO was included in the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (P...

Nowadays general learning programs in Bachelor’s degrees in engineering have gradually adapted towards the inclusion of more electronics oriented subjects. The prominent growth of technology applications reveals its influence on the design of such education plans at university. Most of them introduce advanced methodologies, which in most cases, are...

In this paper, we compare four different methods to estimate nanoparticle diameters from optical absorption measurements, using transmission electron microscopy (TEM) images as a reference for the nanoparticle size. Three solutions of colloidal nanoparticles coated with thiophenol with different diameters were synthesized by thiolate decomposition....

Mobile robotics has become an essential content in many subjects within most Bachelor’s and Master’s degrees in engineering. Visual sensors have emerged as a powerful tool to perform reliable localization and mapping tasks for a mobile robot. Moreover, the use of images permits achieving other high level tasks such as object and people detection, r...

In this work, we present a simulation software that permits designing and testing several types of controllers based on both classical and modern control theory. It has been created using Easy JavaScript Simulations, since this software permits implementing interactive simulations of physical systems in a quick and intuitive way. This laboratory co...

This approach presents a localization technique within mobile robotics sustained by visual sensory data fusion. A regression inference framework is designed with the aid of informative data models of the system, together with support of probabilistic techniques such as Gaussian Processes. As a result, the visual data acquired with a catadioptric se...

Over the past few decades, the incipient growth of technology applications sustained by electronics has contributed to the adaption of learning programs in many engineering degrees at university, fostering the presence of electronics subjects. This highlights the paramount importance of improving the teaching of electronics, especially in the first...

Currently, many tasks can be carried out using mobile robots. These robots must be able to estimate their position in the environment to plan their actions correctly. Omnidirectional vision sensors constitute a robust choice to solve this problem, since they provide the robot with complete information from the environment where it moves. The use of...

This work presents an approach to visual data fusion with omnidirectional imaging in the field of mobile robotics. An inference framework is established through Gaussian processes (GPs) and Information gain metrics, in order to fuse visual data between poses of the robot. Such framework permits producing a probability distribution of feature matchi...

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La localización y creación de mapas son dos tareas que los robots móviles autónomos deben desarrollar. Por ello, se han llevado a cabo numerosas investigaciones sobre estos temas, proponiendo diferentes métodos para abordar estos problemas. Este trabajo describe brevemente algunas posibilidades para mejorar la tarea de navegación utilizando descrip...

This work presents a visual information fusion approach for robust probability-oriented feature matching. It is sustained by omnidirectional imaging, and it is tested in a visual localization framework, in mobile robotics. General visual localization methods have been extensively studied and optimized in terms of performance. However, one of the ma...

In this work, a framework is proposed to build topological models in mobile robotics, using an omnidirectional vision sensor as the only source of information. The model is structured hierarchically into three layers, from one high-level layer which permits a coarse estimation of the robot position to one low-level layer to refine this estimation e...

This work presents a robust visual localization technique based on an omnidirectional monocular sensor for mobile robotics applications. We intend to overcome the non-linearities and instabilities that the camera projection systems typically introduce, which are especially relevant in catadioptric sensors. In this paper, we come up with several con...

This article presents a visual localization technique based solely on the use of omnidirectional images, within the framework of mobile robotics. The proposal makes use of the epipolar constraint, adapted to the omnidirectional reference, in order to deal with matching point detection, which ultimately determines a motion transformation for localiz...

This work presents an improved visual odometry using omnidirectional images. The main purpose is to generate a reliable prior input which enhances the SLAM (Simultaneous Localization and Mapping) estimation tasks within the framework of navigation in mobile robotics, in detriment of the internal odometry data. Generally, standard SLAM approaches ex...

Mobile robotics has experienced an important proliferation in the recent days, with many fields of application available. A great variety of different mobile robots are present in different sectors of society, most of which are designated as autonomous. This term implies that the robot manages to operate itself, without any special supervision. To...

La localización de robots, junto a la creación de mapas y planificación, es una tarea fundamental que permite la navegación autónoma de estos dispositivos en un entorno desconocido. En este trabajo se presenta un método para calcular la transformación entre dos poses del robot que se desplaza en un entorno en el que pueden darse cambios en la altur...

This paper presents a novel mechanism to initiate new views within the map building process for an EKF-based visual SLAM (Simultaneous Localization and Mapping) approach using omnidirectional images. In presence of non-linearities, the EKF is very likely to compromise the final estimation. Particularly, the omnidirectional observation model induces...

This paper describes an approach to the problem of Simultaneous Localization and Mapping (SLAM) based on Stochastic Gradient Descent (SGD) and using omnidirectional images. In the field of mobile robot applications, SGD techniques have never been evaluated with information gathered by visual sensors. This work proposes a SGD algorithm within a SLAM...

This chapter focuses on the problem of Simultaneous Localization and Mapping (SLAM) using visual information from the environment. We exploit the versatility of a single omnidirectional camera to carry out this task. Traditionally, visual SLAM approaches concentrate on the estimation of a set of visual 3D points of the environment, denoted as visua...

This work presents a purely visual topologic odometry system for robot navigation. Our system is based on a Multi-Scale analysis that allows us to estimate the relative displacement between consecutive omnidirectional images. This analysis uses global appearance techniques to describe the scenes. The visual odometry system also makes use of global...

This paper proposes an appearance-based method to detect loop closure in visual SLAM (Simultaneous Localization and Mapping). To solve this problem, we make use of omnidirectional images and the internal odometry captured by a robot in a real indoor environment. We build an appearance-based model and, subsequently, two maps of the environment are c...

In this work, we present a collection of different techniques oriented to the altitude estimation in topological visual navigation tasks. All the methods use descriptors based on the global appearance of the scenes. The techniques are tested using our own experimental database, which is composed of a set of omnidirectional images captured in real l...

Este trabajo aborda el problema de SLAM (Simultaneous Localization and Mapping), y presenta una solución basada en el algoritmo SGD (Stochastic Gradient Descent). En concreto se plantea un modelo basado en imágenes omnidireccionales. Entre las aplicaciones de la robótica móvil nunca ha sido evaluado el funcionamiento de SGD junto con la información...

The problem of Simultaneous Localization and Mapping (SLAM) is essential in mobile robotics. The obtention of a feasible map of the environment poses a complex challenge, since the presence of noise arises as a major problem which may gravely affect the estimated solution. Consequently, a SLAM algorithm has to cope with this issue but also with the...

This work presents a solution for the problem of Simultaneous Localization and Mapping (SLAM) based on a Stochastic Gradient Descent (SGD) technique and using omnidirectional images. In the field of applications of mobile robotics, SGD has never been tested with visual information obtained from the environment. This paper suggests the introduction...

This paper deals with the problem of Simultaneous Localization and Mapping (SLAM). The solution presented is based on the utilisation of a set of images to represent the environment. In this way, the estimation of the map considers the computation of the position and orientation of a set of omnidirectional views captured from the environment. The p...

In the field of mobile autonomous robots, visual odometry entails the retrieval of a motion transformation between two consecutive poses of the robot by means of a camera sensor solely. A visual odometry provides an essential information for trajectory estimation in problems such as Localization and SLAM (Simultaneous Localization and Mapping). In...

In this paper we deal with the problem of robot localization using the visual information provided by a single omnidirectional camera mounted on the robot, using techniques based on the global appearance of panoramic images. Our main objective consists in showing the feasibility of the appearance-based approaches in a localization task in a relativ...

In this paper we focus on the problem of Simultaneous Localization and Mapping (SLAM) using visual information obtained from the environment. In particular, we propose the use of a single omnidirectional camera to carry out this task. Many approaches to visual SLAM concentrate on the estimation of the position of a set of 3D points, commonly denote...

En este artículo se describe una solución al problema de SLAM (Simultaneous Localization and Mapping) basado en una única cámara omnidireccional. Consideramos que el robot está equipado con un único sensor catadióptrico y que es capaz de extraer puntos de interés de las imágenes. En esta solución, el mapa está representado por un conjunto de imágen...

This paper describes an approach to the Simultaneous Localization and Mapping (SLAM) problem using a single omnidirectional camera. We consider that the robot is equipped with a catadioptric sensor and is able to extract interest points from the images. In the approach, the map is represented by a set of omnidirectional images and their positions....

Cooperative vehicular communications are being developed to improve road safety and traffic management by assisting drivers and road authorities with real-time and comprehensive traffic information. In the study of such systems, large-scale simulation research has been identified as a necessary resource to realistically evaluate cooperative vehicul...