Norbert Elkmann Bert Reimann Erik Schulenburg Heiko Althoff Automated Inspection System for Large Underground Concrete Pipes Under Operating Conditions. 567-578 2005 FSR http://dx.doi.org/10.1007/978-3-540-33453-8_47 conf/fsr/2005 db/conf/fsr/fsr2005.html#ElkmannRSA05