by admin

Unified Temporal and Spatial Calibration for Multi-Sensor Systems

July 17, 2014 in ETHZ-ASL, Publications, year 4 by admin

Paul Furgale, Joern Rehder and Roland Siegwart

IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

In order to increase accuracy and robustness in state estimation for robotics, a growing number of applications rely on data from multiple complementary sensors. For the best performance in sensor fusion, these different sensors must be spatially and temporally registered with respect to each other. To this end, a number of approaches have been developed to estimate these system parameters in a two stage process, first estimating the time offset and subsequently solving for the spatial transformation between sensors. In this work, we present on a novel framework for jointly estimating the temporal offset between measurements of different sensors and their spatial displacements with respect to each other. The approach is enabled by continuous-time batch estimation and extends previous work by seamlessly incorpo- rating time offsets within the rigorous theoretical framework of maximum likelihood estimation. Experimental results for a camera to inertial measurement unit (IMU) calibration prove the ability of this framework to accurately estimate time offsets up to a fraction of the smallest measurement period.


@inproceedings{furgale_iros13,
doi = { 10.1109/IROS.2013.6696514 },
year = { 2013 },
url = { bib/furgale_iros13.pdf },
title = { Unified Temporal and Spatial Calibration for Multi-Sensor Systems },
pages = { 1280--1286 },
month = { 3--7 November },
booktitle = { Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) },
author = { Paul Furgale and Joern Rehder and Roland Siegwart },
address = { Tokyo, Japan },
}

by admin

OpenGV: A Unified and Generalized Approach to Real-Time Calibrated Geometric Vision

July 17, 2014 in ETHZ-ASL, Publications, year 4 by admin

Laurent Kneip and Paul Timothy Furgale

IEEE International Conference on Robotics and Automation (ICRA) 2014

OpenGV is a new C++ library for calibrated real- time 3D geometric vision. It unifies both central and non-central absolute and relative camera pose computation algorithms within a single library. Each problem type comes with minimal and non-minimal closed-form solvers, as well as non-linear iterative optimization and robust sample consensus methods. OpenGV therefore contains an unprecedented level of com- pleteness with regard to calibrated geometric vision algorithms, and it is the first library with a dedicated focus on a unified real-time usage of non-central multi-camera systems, which are increasingly popular in robotics and in the automotive industry. This paper introduces OpenGV¿s flexible interface and abstraction for multi-camera systems, and outlines the performance of all contained algorithms. It is our hope that the introduction of this open-source platform will motivate people to use it and potentially also include more algorithms, which would further contribute to the general accessibility of geometric vision algorithms, and build a common playground for the fair comparison of different solutions.


@inproceedings{kneip_icra14,
year = { 2014 },
codeurl = { http://laurentkneip.github.io/opengv/ },
note = { (\href{http://laurentkneip.github.io/opengv/}{code}) },
pages = { 1--8 },
url = { bib/kneip_icra14.pdf },
title = { OpenGV: A Unified and Generalized Approach to Real-Time
Calibrated Geometric Vision },
booktitle = { Proceedings of the IEEE International Conference on
Robotics and Automation (ICRA) },
author = { Laurent Kneip and Paul Timothy Furgale },
month = { May 3 -- June 7 },
address = { Hong Kong, China },
}

by admin

Associating Uncertainty with Three-Dimensional Poses for use in Estimation Problems

July 17, 2014 in ETHZ-ASL, Journals, Publications, year 4 by admin

Barfoot, Furgale

Robotics, IEEE Transactions on, 30(3), pp. 679-693

In this paper, we provide specific and practical approaches to associate uncertainty with 4 ?? 4 transformation matrices, which is a common representation for pose variables in 3-D space. We show constraint-sensitive means of perturbing transformation matrices using their associated exponential-map generators and demonstrate these tools on three simple-yet-important estimation problems: 1) propagating uncertainty through a compound pose change, 2) fusing multiple measurements of a pose(e.g., for use in pose-graph relaxation), and 3) propagating uncertainty on poses (and landmarks) through a nonlinear camera model. The contribution of the paper is the presentation of the theoretical tools, which can be applied in the analysis of many problems involving 3-D pose and point variables.


@article{barfoot_tro14,
year = { 2014 },
title = { Associating Uncertainty with Three-Dimensional Poses for
use in Estimation Problems },
codeurl = { http://asrl.utias.utoronto.ca/code/barfoot_tro14.zip },
journal = { Robotics, IEEE Transactions on },
author = { Barfoot and Furgale },
pages = { 679-693 },
number = { 3 },
volume = { 30 },
month = { jun },
doi = { 10.1109/TRO.2014.2298059 },
}

by admin

Presentation at Swiss Associaton for E-Mobility

July 10, 2014 in News by admin


The V-Charge project is going to be presented at the annual conference and general meeting of the swiss association for e-mobility on July 28th, 2014. For further information and online registration visit http://www.e-mobile.ch.