Automated sewer pipe inspection through image processing

An innovative inspection method to assess the condition of sewer pipes is proposed in this paper. The standard sewer inspection technique, based on closed-circuit television systems, has a relatively poor performance; a video camera is mounted on a robot and the video recording is provided off-line to an engineer who classifies any defects. The focus of this research is the automated identification and location of discontinuities in the internal surface of sewers. The transducer used is an assembly of a CCD camera and optical elements to generate a ring-shaped laser pattern. The automated inspection method consists of several stages including the segmentation of the image into characteristic geometric features and potential defect regions. Automatic recognition, rating and classification of pipe defects are carried out by means of the computation of a partial histogram based on adaptive image processing techniques. Experiments in a realistic environment have been conducted and results are presented.