A pipe-profiling adapter for CCTV inspection cameras: development of a pipe-profiling instrument

The principle of the optical section has been used to develop a profiling attachment for CCTV pipe inspection cameras. A light source, placed in front of the camera, projects a ring of light onto the pipe wall, which is then viewed by the camera. Any distortion in the pipe wall will be made visible by the light ring. The CCTV image is digitized by an electronic frame grabber and the light ring image is located by specially developed pattern-matching software. The light ring shape is then analysed mathematically using a radial descriptor, which allows any distortion to be represented in terms of a Fourier series. The device has been tested in the laboratory and in the field, and has been used to examine pipe degradation both in sewers and in water mains.