A technology for sewer pipe inspection (Part 2): Experimental assessment of a new laser profiler for sewer defect detection and quantification

In order to test the laser-scanning device presented by Stanić, Lepot, Catieau, Langeveld and Clemens [1], laboratory experiments have been performed. Various objects, covering a wide range of sizes, shapes, materials, colours and reflectiveness, have been installed in a concrete pipe and scanned by the prototype in order to identify potential object characteristics that may affect measurement uncertainty and/or create bias. By taking into account both uncertainties (on scanned and measured sizes), scanned dimensions have been compared to measurements performed with a calliper or a ruler: overall the values are mutually consistent. The proposed prototype is suitable for sewer inspections: displaced joints, cracks, deposits can be accurately measured without any bias by comparison to CCTV. Uncertainty in the measurement appears to be unaffected by humidity or fat deposits.