SEWER PIPE DEFORMATION ASSESSMENT BY IMAGE-ANALYSIS OF VIDEO SURVEYS

A system for the practical use of computer vision techniques is presen ted for the automatic assessment of the structural condition of sewers from video images. The system can provide accuracy, efficiency and ec onomy of sewer pipe examination. The main efforts of the paper have be en placed on investigations of algorithms and techniques for image pro cessing, pipe-joint shape analysis and discrimination, and crack detec tion. Experiments show that over 85% of the pipe-joint boundaries can be extracted successfully from video images, and for pipe-joints with very low aspect ratio (AP<0.05), the measurement error in AP is no mor e than 0.01. This kind of accuracy is of great significance in sewer p ipe structural surveys, and cannot be achieved by visual inspection of the video images. (C) 1997 Pattern Recognition Society. Published by Elsevier Science Ltd.