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Peer-reviewed Journal Articles

• Formation Control Driven by Cooperative Object Tracking, Pedro Lima, Aamir Ahmad, A. Dias, A. Conceição, A. Moreira, E. Silva, L. Almeida, L. Oliveira, T. Nascimento, Robotics and Autonomous Systems (RAS), 2014, ISSN 0921-8890, http://dx.doi.org/10.1016/j.robot.2014.08.018.

• 3D to 2D bijection for spherical objects under equidistant fisheye projection, Aamir Ahmad, João Xavier, José Santos-Victor, Pedro Lima, Computer Vision and Image Understanding (CVIU), Volume 125, August 2014, Pages 172-183, ISSN 1077-3142, http://dx.doi.org/10.1016/j.cviu.2014.04.004.
  • Click to read abstract The core problem addressed in this article is the 3D position detection of a spherical object of known-radius in a single image frame, obtained by a dioptric vision system consisting of only one fisheye lens camera that follows equidistant projection model. The central contribution is a bijection principle between a known-radius spherical object’s 3D world position and its 2D projected image curve, that we prove, thus establishing that for every possible 3D world position of the spherical object, there exists a unique curve on the image plane if the object is projected through a fisheye lens that follows equidistant projection model. Additionally, we present a setup for the experimental verification of the principle’s correctness. In previously published works we have applied this principle to detect and subsequently track a known-radius spherical object.

• Multi-Robot Cooperative Spherical-Object Tracking in 3D Space Based on Particle Filters, Aamir Ahmad and Pedro Lima, Robotics and Autonomous Systems (RAS), Volume 61, Issue 10, October 2013, Pages 1084-1093, ISSN 0921-8890, http://dx.doi.org/10.1016/j.robot.2012.12.008.
  • Click to read abstract This article presents a cooperative approach for tracking a moving spherical object in 3D space by a team of mobile robots equipped with sensors, in a highly dynamic environment. The tracker’s core is a particle filter, modified to handle, within a single unified framework, the problem of complete or partial occlusion for some of the involved mobile sensors, as well as inconsistent estimates in the global frame among sensors, due to observation errors and/or self-localization uncertainty. We present results supporting our approach by applying it to a team of real soccer robots tracking a soccer ball, including comparison with ground truth.

Peer-reviewed Book Chapters

• Cooperative Localization Based on Visually Shared Objects, Pedro Lima, P. Santos, R. Oliveira, Aamir Ahmad, J. Santos, RoboCup 2010: Robot Soccer World Cup XIV, Springer-Verlag, Berlin, Heidelberg 350-361. Series: Lecture Notes in Computer Science, Vol.6556 Subseries: Lecture Notes in Artificial Intelligence. Editors: Ruiz-del-Solar, Javier; Chown, Eric; Ploeger, Paul G.

Peer-reviewed Conference Papers

• Towards Optimal Robot Navigation in Urban Homes, Rodrigo Ventura, Aamir Ahmad, RoboCup Symposium 2014, João Pessoa, Brazil.
• Cooperative Robot Localization and Target Tracking based on Least Squares Minimization, Aamir Ahmad, Gian Diego Tipaldi, Pedro Lima and Wolfram Burgard, IEEE International Conference on Robotics and Automation (ICRA 2013), Karlsruhe, Germany.
• Perception-Driven Multi-Robot Formation Control, Aamir Ahmad, Tiago Nascimento, Andre G. S. Conceicao, Antonio Paulo Moreira and Pedro Lima, IEEE International Conference on Robotics and Automation (ICRA 2013), Karlsruhe, Germany.
• Unknown-Color Spherical Object Detection and Tracking, A. Troppan, E. Guerreiro, F. Celiberti, G. Santos, Aamir Ahmad, Pedro Lima, Robotica 2013 - 13th International Conference on Autonomous Robot Systems and Competitions, Lisbon, Portugal, 2013.
• Multi-Robot Cooperative Object Tracking Based on Particle Filters, Aamir Ahmad and Pedro Lima, Proc. of European Conference on Mobile Robots, Örebro, Sweden, 2011. Voted by the reviewers and the conference participants as one of the best papers presented.
• Cooperative Localization Based on Visually Shared Objects, Pedro Lima, J. Santos, P. Santos, R. Oliveira, Aamir Ahmad, Proc. of RoboCup2010 Symposium, Singapore, 2010.
• Background Subtraction Based on Rank Constraint for Point Trajectories, Aamir Ahmad, Alessio Del Bue, Pedro Lima, Proc. of RecPad 2009 - 15th Portuguese Conference on Pattern Recognition, Aveiro, Portugal, 2009.
• Probabilistic Roadmap Method and Real Time Gait Changing Technique Implementation for Travel Time Optimization on a Designed Six-legged Robot, Aamir Ahmad, Proc. of ISR 2008 - 39th International Symposium on Robotics, Seoul, South Korea, 2008.

Peer-reviewed Project-related Papers

• The RoCKIn(at)Home User Story, Sven Schneider, Frederik Hegger, Gerhard K. Kraetzschmar, Francesco Amigoni, Jakob Berghofer, Rainer Bischoff, Andrea Bonarini, Rhama Dwiputra, Luca Iocchi, Pedro Lima, Matteo Matteucci, Daniele Nardi, Iman Awaad, Aamir Ahmad, Giulio Fontana, Nico Hochgeschwender and Viola Schiaffonati, Conference ISR ROBOTIK 2014 (ISR - ROBOTIK 2014), June 2014, Munich, Germany.
• Overview on the RoCKIn(at)Work Challenge, Rhama Dwiputra, Jakob Berghofer, Francesco Amigoni, Rainer Bischoff, Andrea Bonarini, Luca Iocchi, Gerhard K. Kraetzschmar, Pedro Lima, Matteo Matteucci, Daniele Nardi, Aamir Ahmad, Iman Awaad, Giulio Fontana, Frederik Hegger, Nico Hochgeschwender, Viola Schiaffonati and Sven Schneider, Conference ISR ROBOTIK 2014 (ISR - ROBOTIK 2014), June 2014, Munich, Germany.

Project/Technical/Other Reports (Not peer-reviewed)

• RoCKIn@Work in a Nutshell, A. Ahmad, F. Amigoni, I. Awaad, J. Berghofer, R. Bischor, A. Bonarini, R. Dwiputra, F. Hegger, N. Hochgeschwender, L. Iocchi, G. Kraetzschmar, P. Lima, M. Matteucci, D. Nardi, S. Schneider.
• RoCKIn@Home in a Nutshell, A. Ahmad, F. Amigoni, I. Awaad, J. Berghofer, R. Bischoff, A. Bonarini, R. Dwiputra, G. Fontana, F. Hegger, N. Hochgeschwender, L. Iocchi, G. Kraetzschmar, P. Lima, M. Matteucci, D. Nardi, S. Schneider.
• D-2.1.4 RoCKIn@Work - Innovation in Mobile Industrial Manipulation Competition Design, Rule Book, and Scenario Construction, A. Ahmad, I. Awaad, F. Amigoni, J. Berghofer, R. Bischoff, A. Bonarini, R. Dwiputra, F. Hegger, N. Hochgeschwender, L. Iocchi, G. Kraetzschmar, P. U. Lima, M. Matteucci, D. Nardi, S. Schneider.
• D-2.1.1 RoCKIn@Home - A Competition for Domestic Service Robots Competition Design, Rule Book, and Scenario Construction, A. Ahmad, I. Awaad, F. Amigoni, J. Berghofer, R. Bischoff, A. Bonarini, R. Dwiputra, F. Hegger, N. Hochgeschwender, L. Iocchi, G. Kraetzschmar, P. U. Lima, M. Matteucci, D. Nardi, S. Schneider.
• D-1.1 Specification of General Features of Scenarios and Robots for Benchmarking Through Competitions, A. Ahmad, I. Awaad, F. Amigoni, J. Berghofer, R. Bischoff, A. Bonarini, R. Dwiputra, G. Fontana, F. Hegger, N. Hochgeschwender, L. Iocchi, G. Kraetzschmar, P. U. Lima, M. Matteucci, D. Nardi, V. Schaffionati, S. Schneider.
• SocRob-MSL 2013 Team Description Paper for Middle Sized League in RoboCup 2013, Eindhoven, The Netherlands. João Messias, Aamir Ahmad, João Reis, Miguel Serafim, Pedro Lima.
• ISocRob-MSL 2011 Team Description Paper for Middle Sized League in RoboCup 2011, Istanbul, Turkey. João Messias, Aamir Ahmad, João Reis, Fabio Grego, João Sousa and Pedro Lima.
• ISocRob-MSL 2009 Team Description Paper for Middle Sized League in RoboCup 2009, Graz. Pedro Lima, João Santos, João Estilita, Marco Barbosa, Aamir Ahmad, João Carreira.