Paper Info
Title
Online temporal calibration for camera-IMU systems: Theory and algorithms
Abstract
When fusing visual and inertial measurements for motion estimation, each measurement's sampling time must be precisely known. This requires knowledge of the time offset that inevitably exists between the two sensors' data streams. The first contribution of this work is an online approach for estimating this time offset, by treating it as an additional state variable to be estimated along with all other variables of interest (inertial measurement unit (IMU) pose and velocity, biases, camera-to-IMU transformation, feature positions). We show that this approach can be employed in pose-tracking with mapped features, in simultaneous localization and mapping, and in visual-inertial odometry. The second main contribution of this paper is an analysis of the identifiability of the time offset between the visual and inertial sensors. We show that the offset is locally identifiable, except in a small number of degenerate motion cases, which we characterize in detail. These degenerate cases are either (i) cases known to cause loss of observability even when no time offset exists, or (ii) cases that are unlikely to occur in practice. Our simulation and experimental results validate these theoretical findings, and demonstrate that the proposed approach yields high-precision, consistent estimates, in scenarios involving either known or unknown features, with both constant and time-varying offsets.
Year
DOI
Venue
2014
10.1177/0278364913515286
The International Journal of Robotics Research
Keywords
Field
DocType
identifiability analysis,online temporal calibration,time-offset estimation,vision-aided inertial navigation
Computer vision,Observability,Identifiability,Control theory,Odometry,UTC offset,Inertial measurement unit,Artificial intelligence,Motion estimation,Simultaneous localization and mapping,Mathematics,Offset (computer science)
Journal
Volume
Issue
ISSN
33
7
0278-3649
Citations 
PageRank 
References 
17
0.80
29
Authors
2
Name
Order
Citations
PageRank
Mingyang Li127017.60
Anastasios I. Mourikis2101857.50