Page 48: of Marine Technology Magazine (October 2011)

48MTROctober2011 Kongsberg Maritime has completed the world?s longest multi-sensor AUV pipeline survey using one of its HUGIN 1000 Autonomous Underwater Vehicles (AUV). The pipeline inspection took place February 9?11, 2011, in the Hjelte fjord near Bergen, Norway and the HUGIN 1000 was operated from the Royal Norwegian Navy ves- sel HNoMS Malty. The subject of the inspection was two subsea pipelinesgoing to the Mongstad oil refinery. The HUGIN 1000 AUV was equipped with a an advanced suite of KONGS- BERG imaging equipment including the HISAS 1030 synthetic aperture sonar, EM3002 multibeam echo sounder and an optical camera with LED lighting. The instruments were used to inspect around 30 km of subsea pipeline in an 8-hour, two-pass mission. In the first pass, side-scan data from the HISAS 1030 sonar was used to detect and track the pipelines in real- time, using PipeTracker software for pipeline detection and tracking extracted pipe-like features in the sonar images, with a high degree of robustness towards false detections. The PipeTracker software, which was developed in a col- laborative effort with the Norwegian Defence Research Establishment (FFI) in a project funded by the Norwegian Research Council, runs as a plug-in module in the standard HUGIN payload system. The HUGIN 1000 control system in turn uses the identified pipeline tracks to position the vehicle at an optimal range for HISAS imaging. The whole process is fully automated inside the AUV and requires no operator intervention. In the second pass, HUGIN followed the pipeline tracks identified in the first pass at low altitude and inspected the AUV Pipeline Inspection Using the AUVsHugin &RemusBy Even Børhaug & Per Espen Hagen Figure 1 (left): The first 8-hour mission (green line) Figure 2: A single 3 Megapixel camera image. Altitude 4.6 m. Resolution 2x2 mm. MTR#8 (34-49):MTR Layouts 10/10/2011 11:39 AM Page 48