Robotic inspection of ship hull surfaces using a magnetic crawler and a monocular camera
ISSN: 0260-2288
Article publication date: 17 October 2017
Issue publication date: 2 November 2017
Abstract
Purpose
Periodic inspection of large tonnage vessels is critical to assess integrity and prevent structural failures that could have catastrophic consequences for people and the environment. Currently, inspection operations are undertaken by human surveyors, often in extreme conditions. This paper aims to present an innovative system for the automatic visual inspection of ship hull surfaces, using a magnetic autonomous robotic crawler (MARC) equipped with a low-cost monocular camera.
Design/methodology/approach
MARC is provided with magnetic tracks that make it able to climb along the vertical walls of a vessel while acquiring close-up images of the traversed surfaces. A homography-based structure-from-motion algorithm is developed to build a mosaic image and also produce a metric representation of the inspected areas. To overcome low resolution and perspective distortion problems in far field due to the tilted and low camera position, a “near to far” strategy is implemented, which incrementally generates an overhead view of the surface, as long as it is traversed by the robot.
Findings
This paper demonstrates the use of an innovative robotic inspection system for automatic visual inspection of vessels. It presents and validates through experimental tests a mosaicking strategy to build a global view of the structure under inspection. The use of the mosaic image as input to an automatic corrosion detector is also demonstrated.
Practical implications
This paper may help to automate the inspection process, making it feasible to collect images from places otherwise difficult or impossible to reach for humans and automatically detect defects, such as corroded areas.
Originality/value
This paper provides a useful step towards the development of a new technology for automatic visual inspection of large tonnage ships.
Keywords
Acknowledgements
This work has been funded by the EC FP7 SST.2008.5.2.1 Innovative Product Concepts project: Marine INspection rObotic Assistant System, grant n. SCP8-GA-2009-233715-MINOAS, and by the BANDIERA (“Best Action for National Development of International Expert Researchers Activities”) project RITMARE. The authors thank Giorgio Bruzzone, Edoardo Spirandelli and Mauro Giacopelli for their extraordinary contribution to the design, development and test of the MARC platform. Special thanks to the MINOAS consortium and, in particular, to Albena Todorova and all the personnel of Dolphin shipyards who supported with their high professionalism and kindness the field validation of the system.
Citation
Milella, A., Maglietta, R., Caccia, M. and Bruzzone, G. (2017), "Robotic inspection of ship hull surfaces using a magnetic crawler and a monocular camera", Sensor Review, Vol. 37 No. 4, pp. 425-435. https://doi.org/10.1108/SR-02-2017-0021
Publisher
:Emerald Publishing Limited
Copyright © 2017, Emerald Publishing Limited