Cristina Garcia Cifuentes

Alumni

Autonomous Motion

I obtained my Master of Engineering in 2009 from Télécom ParisTech (ENST, France) and Telecom Barcelona (Universitat Politècnica de Catalunya, Spain) after fulfilling a double degree programme. During that time, I specialized in image processing and became interested in artificial intelligence and medical robotics.

I carried out my Master's final project as an intern in the research department of the Airbus Group (formerly EADS) in France, which was my first contact with industrial applications of machine learning.

My Ph.D. thesis topic was in the area of computer vision, on the analysis and classification of unconstrained monocular videos, with a focus on human action recognition. It was jointly supervised by Gabriel Brostow (University College London, UK) and Frédéric Jurie (Université de Caen Basse-Normandie, France) and partially funded by EADS France. We explored video descriptor quantization using random forests, and local and global representations of video for supervised learning.

In 2013 I joined the Perceiving Systems department of the Max Planck Institute for Intelligent Systems (Tübingen, Germany) as a postdoctoral researcher. I worked on optical flow estimation under the supervision of Michael J. Black.

Since June 2015 I am working on vision for robotics at the Autonomous Motion department. My current interest are recursive Bayesian estimation for fusing multiple asynchronous sensors, and enabling continuous interaction of robots with their environment.

Gaussian Filtering as Variational Inference

Decision making requires knowledge of some variables of interest. In the vast majority of real-world problems, these variables are latent, i.e. they cannot be observed directly and must be inferred from available measurements. To maintain an up-to-date distribution over the latent variables, past beliefs have to ...

Manuel Wüthrich Sebastian Trimpe Cristina Garcia Cifuentes Jan Issac Daniel Kappler Franzi Meier Jeannette Bohg Stefan Schaal

Probabilistic Object and Manipulator Tracking

Hand-eye coordination is crucial for capable manipulation of objects. It requires to know the manipulator's and the objects' locations. These locations have to be inferred from sensory data. In this project we work with range sensors, which are wide spread in robotics and provide dense depth images.

...

Manuel Wüthrich Jan Issac Cristina Garcia Cifuentes Jeannette Bohg Claudia Pfreundt Peter Pastor Mrinal Kalakrishnan Daniel Kappler Sebastian Trimpe Franzi Meier Stefan Schaal

Real-Time Perception meets Reactive Motion Generation

Jeannette Bohg Daniel Kappler Franzi Meier Jan Issac Jim Mainprice Cristina Garcia Cifuentes Manuel Wüthrich Vincent Berenz Stefan Schaal Nathan Ratliff

9 results (View BibTeX file of all listed publications)

2018

Real-time Perception meets Reactive Motion Generation

Kappler, D., Meier, F., Issac, J., Mainprice, J., Garcia Cifuentes, C., Wüthrich, M., Berenz, V., Schaal, S., Ratliff, N., Bohg, J.

IEEE Robotics and Automation Letters, 3(3):1864-1871, July 2018 (article)

Abstract

We address the challenging problem of robotic grasping and manipulation in the presence of uncertainty. This uncertainty is due to noisy sensing, inaccurate models and hard-to-predict environment dynamics. Our approach emphasizes the importance of continuous, real-time perception and its tight integration with reactive motion generation methods. We present a fully integrated system where real-time object and robot tracking as well as ambient world modeling provides the necessary input to feedback controllers and continuous motion optimizers. Specifically, they provide attractive and repulsive potentials based on which the controllers and motion optimizer can online compute movement policies at different time intervals. We extensively evaluate the proposed system on a real robotic platform in four scenarios that exhibit either challenging workspace geometry or a dynamic environment. We compare the proposed integrated system with a more traditional sense-plan-act approach that is still widely used. In 333 experiments, we show the robustness and accuracy of the proposed system.

arxiv video video link (url) DOI Project Page [BibTex]

2018

am Kappler, D., Meier, F., Issac, J., Mainprice, J., Garcia Cifuentes, C., Wüthrich, M., Berenz, V., Schaal, S., Ratliff, N., Bohg, J. Real-time Perception meets Reactive Motion Generation IEEE Robotics and Automation Letters, 3(3):1864-1871, July 2018 (article)

arxiv video video link (url) DOI Project Page [BibTex]

2017

Probabilistic Articulated Real-Time Tracking for Robot Manipulation

(Best Paper of RA-L 2017, Finalist of Best Robotic Vision Paper Award of ICRA 2017)

Garcia Cifuentes, C., Issac, J., Wüthrich, M., Schaal, S., Bohg, J.

IEEE Robotics and Automation Letters (RA-L), 2(2):577-584, April 2017 (article)

Abstract

We propose a probabilistic filtering method which fuses joint measurements with depth images to yield a precise, real-time estimate of the end-effector pose in the camera frame. This avoids the need for frame transformations when using it in combination with visual object tracking methods. Precision is achieved by modeling and correcting biases in the joint measurements as well as inaccuracies in the robot model, such as poor extrinsic camera calibration. We make our method computationally efficient through a principled combination of Kalman filtering of the joint measurements and asynchronous depth-image updates based on the Coordinate Particle Filter. We quantitatively evaluate our approach on a dataset recorded from a real robotic platform, annotated with ground truth from a motion capture system. We show that our approach is robust and accurate even under challenging conditions such as fast motion, significant and long-term occlusions, and time-varying biases. We release the dataset along with open-source code of our approach to allow for quantitative comparison with alternative approaches.

arXiv video code and dataset video PDF DOI Project Page [BibTex]

2017

am Garcia Cifuentes, C., Issac, J., Wüthrich, M., Schaal, S., Bohg, J. Probabilistic Articulated Real-Time Tracking for Robot Manipulation IEEE Robotics and Automation Letters (RA-L), 2(2):577-584, April 2017 (article)

arXiv video code and dataset video PDF DOI Project Page [BibTex]

2016

A New Perspective and Extension of the Gaussian Filter

Wüthrich, M., Trimpe, S., Garcia Cifuentes, C., Kappler, D., Schaal, S.

The International Journal of Robotics Research, 35(14):1731-1749, December 2016 (article)

Abstract

The Gaussian Filter (GF) is one of the most widely used filtering algorithms; instances are the Extended Kalman Filter, the Unscented Kalman Filter and the Divided Difference Filter. The GF represents the belief of the current state by a Gaussian distribution, whose mean is an affine function of the measurement. We show that this representation can be too restrictive to accurately capture the dependences in systems with nonlinear observation models, and we investigate how the GF can be generalized to alleviate this problem. To this end, we view the GF as the solution to a constrained optimization problem. From this new perspective, the GF is seen as a special case of a much broader class of filters, obtained by relaxing the constraint on the form of the approximate posterior. On this basis, we outline some conditions which potential generalizations have to satisfy in order to maintain the computational efficiency of the GF. We propose one concrete generalization which corresponds to the standard GF using a pseudo measurement instead of the actual measurement. Extending an existing GF implementation in this manner is trivial. Nevertheless, we show that this small change can have a major impact on the estimation accuracy.

am ics

PDF DOI Project Page [BibTex]

2016

am ics Wüthrich, M., Trimpe, S., Garcia Cifuentes, C., Kappler, D., Schaal, S. A New Perspective and Extension of the Gaussian Filter The International Journal of Robotics Research, 35(14):1731-1749, December 2016 (article)

PDF DOI Project Page [BibTex]

Interlocking Perception-Action Loops at Multiple Time Scales - A System Proposal for Manipulation in Uncertain and Dynamic Environments

Bohg, J., Kappler, D., Meier, F., Ratliff, N., Mainprice, J., Issac, J., Wüthrich, M., Garcia Cifuentes, C., Berenz, V., Schaal, S.

In International Workshop on Robotics in the 21st century: Challenges and Promises, September 2016 (inproceedings)

Workshop Webpage Extended Abstract Project Page [BibTex]

am Bohg, J., Kappler, D., Meier, F., Ratliff, N., Mainprice, J., Issac, J., Wüthrich, M., Garcia Cifuentes, C., Berenz, V., Schaal, S. Interlocking Perception-Action Loops at Multiple Time Scales - A System Proposal for Manipulation in Uncertain and Dynamic Environments In International Workshop on Robotics in the 21st century: Challenges and Promises, September 2016 (inproceedings)

Workshop Webpage Extended Abstract Project Page [BibTex]

Robust Gaussian Filtering using a Pseudo Measurement

Wüthrich, M., Garcia Cifuentes, C., Trimpe, S., Meier, F., Bohg, J., Issac, J., Schaal, S.

In Proceedings of the American Control Conference, Boston, MA, USA, July 2016 (inproceedings)

Abstract

Most widely-used state estimation algorithms, such as the Extended Kalman Filter and the Unscented Kalman Filter, belong to the family of Gaussian Filters (GF). Unfortunately, GFs fail if the measurement process is modelled by a fat-tailed distribution. This is a severe limitation, because thin-tailed measurement models, such as the analytically-convenient and therefore widely-used Gaussian distribution, are sensitive to outliers. In this paper, we show that mapping the measurements into a specific feature space enables any existing GF algorithm to work with fat-tailed measurement models. We find a feature function which is optimal under certain conditions. Simulation results show that the proposed method allows for robust filtering in both linear and nonlinear systems with measurements contaminated by fat-tailed noise.

am ics

Web link (url) DOI Project Page Project Page [BibTex]

am ics Wüthrich, M., Garcia Cifuentes, C., Trimpe, S., Meier, F., Bohg, J., Issac, J., Schaal, S. Robust Gaussian Filtering using a Pseudo Measurement In Proceedings of the American Control Conference, Boston, MA, USA, July 2016 (inproceedings)

Web link (url) DOI Project Page Project Page [BibTex]

Depth-based Object Tracking Using a Robust Gaussian Filter

Issac, J., Wüthrich, M., Garcia Cifuentes, C., Bohg, J., Trimpe, S., Schaal, S.

In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA) 2016, IEEE, IEEE International Conference on Robotics and Automation, May 2016 (inproceedings)

Abstract

We consider the problem of model-based 3D- tracking of objects given dense depth images as input. Two difficulties preclude the application of a standard Gaussian filter to this problem. First of all, depth sensors are characterized by fat-tailed measurement noise. To address this issue, we show how a recently published robustification method for Gaussian filters can be applied to the problem at hand. Thereby, we avoid using heuristic outlier detection methods that simply reject measurements if they do not match the model. Secondly, the computational cost of the standard Gaussian filter is prohibitive due to the high-dimensional measurement, i.e. the depth image. To address this problem, we propose an approximation to reduce the computational complexity of the filter. In quantitative experiments on real data we show how our method clearly outperforms the standard Gaussian filter. Furthermore, we compare its performance to a particle-filter-based tracking method, and observe comparable computational efficiency and improved accuracy and smoothness of the estimates.

am ics

Video Bayesian Object Tracking Library Bayesian Filtering Framework Object Tracking Dataset link (url) DOI Project Page Project Page [BibTex]

am ics Issac, J., Wüthrich, M., Garcia Cifuentes, C., Bohg, J., Trimpe, S., Schaal, S. Depth-based Object Tracking Using a Robust Gaussian Filter In Proceedings of the IEEE International Conference on Robotics and Automation (ICRA) 2016, IEEE, IEEE International Conference on Robotics and Automation, May 2016 (inproceedings)

Video Bayesian Object Tracking Library Bayesian Filtering Framework Object Tracking Dataset link (url) DOI Project Page Project Page [BibTex]

2013

Leveraging Weak Supervision for Video Understanding

Garcia Cifuentes, C.

University College London, 2013 (phdthesis)

link (url) [BibTex]

2013

Garcia Cifuentes, C. Leveraging Weak Supervision for Video Understanding University College London, 2013 (phdthesis)

link (url) [BibTex]

2012

Motion Models that Only Work Sometimes

Garcia Cifuentes, C., Sturzel, M., Jurie, F., Brostow, G.

In Proceedings of the British Machine Vision Conference, BMVC 2012, pages: 55.1-55.12, (Editors: Bowden, Richard and Collomosse, John and Mikolajczyk, Krystian), BMVA Press, Surrey, UK, September 2012 (inproceedings)

Project page [BibTex]

2012

Garcia Cifuentes, C., Sturzel, M., Jurie, F., Brostow, G. Motion Models that Only Work Sometimes In Proceedings of the British Machine Vision Conference, BMVC 2012, pages: 55.1-55.12, (Editors: Bowden, Richard and Collomosse, John and Mikolajczyk, Krystian), BMVA Press, Surrey, UK, September 2012 (inproceedings)

Project page [BibTex]

2010

How to Learn a Learning System: Automatic Decomposition of a Multiclass Task with Probability Estimates

Garcia Cifuentes, C., Sturzel, M.

In ICAART 2010 - Proceedings of the International Conference on Agents and Artificial Intelligence, 1, pages: 589-594, (Editors: Filipe, Joaquim and Fred, Ana L. N. and Sharp, Bernadette), INSTICC Press, Valencia, Spain, January 2010 (inproceedings)

[BibTex]

2010

Garcia Cifuentes, C., Sturzel, M. How to Learn a Learning System: Automatic Decomposition of a Multiclass Task with Probability Estimates In ICAART 2010 - Proceedings of the International Conference on Agents and Artificial Intelligence, 1, pages: 589-594, (Editors: Filipe, Joaquim and Fred, Ana L. N. and Sharp, Bernadette), INSTICC Press, Valencia, Spain, January 2010 (inproceedings)

[BibTex]