IMAGE-BASED DAMAGE ASSESSMENT FOR UNDERWATER INSPECTIONS

Inspection is crucial to the management of ageing infrastructure. Visual information on structures is regularly collected but very little work exists on its organised and quantitative analysis, even though image processing can significantly enhance these inspection processes and transfer real financial and safety benefits to the managers, owners and users. Additionally, new opportunities exist in the fast evolving sectors of wind and wave energy to add value to image-based inspection techniques.

This book is a first for structural engineers and inspectors who wish to harness the full potential of cameras as an inspection tool. It is particularly directed to the inspection of offshore and marine structures and the application of image-based methods in underwater inspections. It outlines a set of best practice guidelines for obtaining imagery, then the fundamentals of image processing are covered along with several image processing techniques which can be used to assess multiple damage forms: crack detection, corrosion detection, and depth analysis of marine growth on offshore structures. The book provides benchmark performance measures for these techniques under various visibility conditions using an image repository which will help inspectors to envisage the effectiveness of the techniques when applied. MATLAB® scripts and access to the underwater image repository are included so readers can run these techniques themselves.

Practising engineers and managers of infrastructure assets are guided in image processing based inspection. Researchers can use this book as a primer, and it also suits advanced graduate courses in infrastructure management or on applied image processing.

Dr. Michael O’Byrne (B.E., University College Cork Ireland) is a post-doctoral researcher in the School of Engineering at University College Cork, Ireland. His research interests are image based Non-Destructive Testing techniques for monitoring offshore structures. His doctorate investigated Automatic Detection of Damage using Image Based Techniques in Underwater Marine Structures. It involved using the latest research in image processing to detect and quantify damage that affects offshore structures, such as cracks, corrosion and bio-fouling. Currently, Dr. O’Byrne is developing new image processing techniques for infrastructure maintenance management and also looking at how underwater image processing based inspection can help estimating changes in hydrodynamic loads to structures due to bio-fouling.

Dr. Bidisha Ghosh, Assistant Professor, Trinity College Dublin, is an expert of statistical modelling, artificial intelligence techniques and data analysis. She applies these techniques to transportation networks, hydrological networks and infrastructure management. Her work in image processing relates to structural damage detection, infrastructure management, traffic monitoring, crash-barrier design and the development of a benchmark repository for such purposes.

Professor Franck Schoefs, from the University of Nantes, France, is a leading figure in the field of structural reliability and inspection-led maintenance management. He works on probabilistic modelling of inspections results and on site measurements from structural health monitoring. Major applications of his work are in bridge engineering, offshore structures and marine renewable energy. He is an expert of probabilistic modelling of marine growth on offshore structures.

Dr. Vikram Pakrashi is a Chartered Engineer and the director of Dynamical Systems and Risk Laboratory, School of Engineering, University College Cork. His research interests strongly feature infrastructure maintenance management and Structural Health Monitoring. Dr. Pakrashi has experience of inspecting, instrumenting and assessing numerous damaged structures at different levels of complexity and detail.