Date Approved


Embargo Period


Document Type


Degree Name

M.S. in Engineering


Electrical & Computer Engineering


Henry M. Rowan College of Engineering


Mandayam, Shreekanth


Natural gas pipelines--Maintenance and repair; Natural gas pipelines--United States


Electrical and Computer Engineering


The natural gas transmission pipeline network in the United States is a key component of the nation's energy supply infrastructure and extends for over 280,000 miles and has an average age of over 60 years. The integrity of the pipeline is maintained by periodic inline inspections using magnetic or ultrasonic pigs. Defect characterization algorithms developed using current pigging data are hampered by the fact that single inspection techniques (either magnetic or ultrasonic) do not yield sufficient information for accurately and repeatably characterizing defects. This thesis demonstrates that defect characterization algorithms using multiple inspection techniques can accomplish this task. In particular, it is shown that the varying depth of a surface breaking pipeline defect can be precisely determined using a combination of multiple inspection methods. Also the precise location of such defects can be predicted using dissimilar interrogation methods. A judicious combination of signal and image processing strategies, including geometric transformations, radial basis function approximations and Parzen windows density estimations, have been used to fuse data from both homogeneous and heterogeneous sensors. Application results using data from laboratory experiments demonstrate the consistency and efficacy of the proposed approach.