Assists in the detection and recognition of structural defects in pipelines by automatic analysis of XtraSonic images.

Summary TRAPIL is a French company in charge of the operation and maintenance of hydrocarbon pipelines. The maintenance of buried pipelines requires the passage of scrapers equipped with ultrasonic probes that map the pipeline structure, which is then analyzed by hand in order to detect and identify the various defects that may appear or evolve.The objective of this thesis is to provide an algorithmic solution to accelerate and complete the work of analysts using modern methods of image and signal processing.Our approach follows the modus operandi of experts and is divided into three parts.First, we perform a detection of butt welds to separate the pipeline into the different tubes that compose it. The probe signals representing the circumference of the pipe are grouped and compressed in a short and long term mean comparison rupture detection, then the resulting signals are merged using a unique weighting allowing a major increase in the contrast between noise and weld, providing a detection and localization almost flawless.The pipes undergo then a first segmentation aiming at eliminating the greatest number of healthy pixels. Using histogram modeling of thickness values by an EM algorithm initialized for our problem, the algorithm follows a recursive principle comparable to split and merge methods to detect and isolate dangerous areas.Finally, the dangerous areas are identified using a random drill, learned from a large number of defect examples. This third part is focused on the study of different pattern recognition methods applied to our new problematic.Through these different steps, the solutions we have provided allow TRAPIL to save significant time on the most tedious tasks of the analysis process (e.g. 30% on weld detection) and offers them new business opportunities, for example the possibility to provide a pre-report to their customers in a few days while the manual analysis is performed that can take more than a month.