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Delfin J.,Robotics and Advanced Manufacturing Group | Mar O.,Computer Science Group | Hayet J.-B.,Computer Science Group | Castelan M.,Robotics and Advanced Manufacturing Group | Arechavaleta G.,Robotics and Advanced Manufacturing Group
IEEE-RAS International Conference on Humanoid Robots | Year: 2012

This paper proposes a novel approach for the simultaneous localization and reconstruction of a 3D object. This reconstruction is done with a small humanoid platform by the only means of monocular vision.We combine (1) a stochastic control approach to decide how to move the robot such that the object can be both localized with respect to the robot and correctly reconstructed, and (2) a space carving approach for the 3D reconstruction of the object that merges the acquired monocular views into a coherent model. We present a set of very promising results obtained with a NAO platform. © 2012 IEEE.


Delfin J.,Robotics and Advanced Manufacturing Group | Becerra H.M.,Research Center en Matematicas | Arechavaleta G.,Robotics and Advanced Manufacturing Group
International Journal of Control | Year: 2016

In this paper, we address the problem of humanoid locomotion guided from information of a monocular camera. The goal of the robot is to reach a desired location defined in terms of a target image, i.e., a positioning task. The proposed approach allows us to introduce a desired time to complete the positioning task, which is advantageous in contrast to the classical exponential convergence. In particular, finite-time convergence is achieved while generating smooth robot velocities and considering the omnidirectional waking capability of the robot. In addition, we propose a hierarchical task-based control scheme, which can simultaneously handle the visual positioning and the obstacle avoidance tasks without affecting the desired time of convergence. The controller is able to activate or inactivate the obstacle avoidance task without generating discontinuous velocity references while the humanoid is walking. Stability of the closed loop for the two task-based control is demonstrated theoretically even during the transitions between the tasks. The proposed approach is generic in the sense that different visual control schemes are supported. We evaluate a homography-based visual servoing for position-based and image-based modalities, as well as for eye-in-hand and eye-to-hand configurations. The experimental evaluation is performed with the humanoid robot NAO. © 2016 Taylor & Francis


Delfin J.,Robotics and Advanced Manufacturing Group | Becerra H.M.,Research Center en Matematicas | Arechavaleta G.,Robotics and Advanced Manufacturing Group
IEEE-RAS International Conference on Humanoid Robots | Year: 2015

In this paper, we propose an approach of following a visual path for humanoid navigation. The problem consists in computing appropriate robot velocities for the humanoid walking task from the visual data shared between the current robot view and a set of target images. Two types of visual controllers are evaluated: a position-based scheme and an image-based scheme. Both of them rely on the estimation of the homography model even for non-planar scenes. We assume that the sequence of target images is given and we focus on the controllers performance. Because classical visual path following controllers generate discontinuous robot velocities, we propose a generic controller (applicable for different types of visual feedback) to alleviate this issue, which is a main contribution of the paper. The stability of such controller is addressed theoretically and verified through experiments with a NAO humanoid robot. © 2014 IEEE.


Hernandez-Rodriguez F.,Robotics and Advanced Manufacturing Group | Castelan M.,Robotics and Advanced Manufacturing Group
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Photometric sampling is a process where the surface normals of an object are estimated through the excitation of the object's surface and a rotating light source around it. The method can be regarded as a special case of photometric stereo when extensive sampling is performed in order to calculate surface normals. The classic photometric sampling approach considers only variations around the azimuth angle of the moving light source. As a consequence, additional attention has to be be paid to the recovery of the light source directions and the removal of specular and shadowed regions. This paper investigates the effect of including variations around the zenith angle of the light source vector in a photometric sampling framework, developing a geometric approach to estimate the surface normal vectors. Experiments show that increasing the number of samples along the zenith variation benefits the estimation of the surface normals. © 2012 Springer-Verlag Berlin Heidelberg.


Sanchez-Escobedo D.,Robotics and Advanced Manufacturing Group | Castelan M.,Robotics and Advanced Manufacturing Group
Pattern Recognition Letters | Year: 2013

This paper addresses the problem of linearly approximating 3D shape from intensities in the context of facial analysis. In other words, given a frontal pose grayscale input face, the direct estimation of its 3D structure is sought through a regression matrix. Approaches falling into this category generally assume that both 2D and 3D features are defined under Cartesian schemes, which is not optimal for the task of novel view synthesis. The current article aims to overcome this issue by exploiting the 3D structure of faces through cylindrical coordinates, aided by the partial least squares regression. In the context of facial shape analysis, partial least squares builds a set of basis faces, for both grayscale and 3D shape spaces, seeking for maximizing shared covariance between projections of the data along the basis faces. Experimental tests show how the cylindrical representations are suitable for the purposes of linear regression, resulting in a benefit for the generation of novel facial views, showing a potential use in model based face identification. © 2012 Elsevier B.V. All rights reserved.


Jarquin G.,Robotics and Advanced Manufacturing Group | Arechavaleta G.,Robotics and Advanced Manufacturing Group | Parra-Vega V.,Robotics and Advanced Manufacturing Group
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2013

This paper proposes a general scheme based on terminal attractors to parametrize operational tasks with respect to time in continuous kinematic controllers. Commonly, a pseudo-inverse operator is applied to solve operational tasks. However, it is known that discontinuities in the control signals appear as a by-product of task transitions during motion execution. In particular, these transitions involve the insertion, removal and swapping of tasks. Recently, some methods have been reported that overcome such discontinuities in the control signals. In this work, we provide time parametrization capabilities to these continuous kinematic controllers in order to handle the time axis of operational tasks at will. Then, we show that the proposed scheme can be naturally extended for the case of prioritized kinematic tasks while preserving continuity under task transitions. Our scheme is validated in a real experiment with a NAO humanoid robot. © 2013 IEEE.


Padilla-Calderon R.,Robotics and Advanced Manufacturing Group | Ordaz-Hernandez K.,Robotics and Advanced Manufacturing Group
2014 IEEE International Autumn Meeting on Power, Electronics and Computing, ROPEC 2014 | Year: 2014

In this paper we present a novel paradigm for reduction of the search space for visual localization of landmarks in deformable linear objects (DLOs) for robotic manipulation tasks. This has been achieved by statistical prediction of the location of the landmarks with a multivariate multiple linear regression model, using position and orientation of the end-effectors of the robot as independent variables and the x-y coordinates of the predicted locations as dependent variables. We implemented this approach with a NAO humanoid robot and a Kinect RGB camera, the results denote a reduction in almost 90% of the search space of the position of 6 landmarks in a deformable linear object with respect to the classical methods in which the search is performed in the whole image. © 2014 IEEE.


Olguin-Diaz E.,Robotics and Advanced Manufacturing Group | Arechavaleta G.,Robotics and Advanced Manufacturing Group | Jarquin G.,Robotics and Advanced Manufacturing Group | Parra-Vega V.,Robotics and Advanced Manufacturing Group
IEEE Transactions on Robotics | Year: 2013

A passivity-based model-free control scheme for an underwater fully actuated vehicle-manipulator system (UVMS) in contact tasks is proposed. Orthogonalized motion and force second-order sliding modes are enforced for all time for the redundant noninertial robotic UVMS, including when it is subject to a class of fluid disturbances. To this end, we first determine the constrained dynamics using the quasi-Lagrangian formulation to explicitly characterize hydrodynamic fluid perturbations. Our scheme aims at exploiting the structural properties of Lagrangian systems, then we derive a mapping between the quasi-Lagrangian UVMS to its equivalent Lagrangian form, and study the conditions for open-loop passivity preservation during the interaction of postures and contact constraints between the end effector of theUVMS and the rigid contact surface of bulky objects in cluttered submarine environments. Internal motions are simultaneously computed by solving, in the tangent subspace of the contact manifold, a hierarchy of secondary tasks to satisfy the posture constraints. More importantly, the solution shapes the extended errors that are used to preserve passivity and to enforce dissipativity so as to guarantee local exponential stability without any knowledge of the complex UVMS dynamics, and the energetic performance of the UVMS in closed-loop. Illustrative simulations are discussed to show the feasibility of the proposed scheme. © 2013 IEEE.


Jarquin G.,Robotics and Advanced Manufacturing Group | Arechavaleta G.,Robotics and Advanced Manufacturing Group | Parra-Vega V.,Robotics and Advanced Manufacturing Group
IEEE International Conference on Intelligent Robots and Systems | Year: 2011

Classical prioritized inverse kinematics (PIK) allows to generate admissible trajectories for redundant robotic systems according to a prioritized finite set of kinematic tasks to simultaneously handle multiple posture constraints. In this paper, we propose a novel regulation scheme that permits to define terminal attractors (TA) at each priority level for satisfying an additional constraint which is the final time. TA were first introduced in the context of movement neuroscience for studying the targeting problem in reaching movements. Based on the underlying properties of TA, we extend PIK methods for achieving desired time convergence of each task while guaranteeing smooth transitions between active and inactive tasks during execution. The proposed scheme is illustrated in simulation with branched robotic manipulators and verified with a real redundant robotic arm. © 2011 IEEE.


Miranda-Hernandez J.,Robotics and Advanced Manufacturing Group | Castelan M.,Robotics and Advanced Manufacturing Group | Torres-Mendez L.A.,Robotics and Advanced Manufacturing Group
IET Computer Vision | Year: 2012

For many tasks, it is necessary to synthesise realistic colour in faces from greyscale values. This is the problem the authors address in this study. Rather than propagating colour information in some regions of the image or transferring colour from an image source to a greyscale using some corresponding criterion, as many colouring systems attempt to do, they seek to synthesise facial colour information using a database of examples. This methodology is divided into two main stages. In the first stage the facial skin tone is predicted through the multiple linear regression method known as partial least squares. This regression allows to define a linear transformation between facial greyscale and colour subspaces. The second stage involves the luminance-α-β (Lαβ) colour transform which is responsible for the recovery of the fine facial detail. The core of the proposed methodology is the combination of statistical subspace analysis with the appropriate colour transform so as to produce realistic facial colourisation results in a direct manner. © 2012 The Institution of Engineering and Technology.

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