Real time pipeline profile extraction using recursive filtering and circle location

This paper describes a pipeline profiling tool which uses a laser to build a 3D model of the inside of a pipe. A robot travels down the pipe finding the profile in real time using a laser and a camera. The laser is used to draw a line around the edge of the pipe; this line is then extracted from acquired images using recursive Gaussian filtering. Three methods were examined for fitting a circle to the profile, two variations of the Hough transform and a random sampling method. The random sampling method was found to be the most flexible and efficient. The extracted profile points were used to construct a 3D model of a pipe section. This model can be viewed using a model viewer written using OpenGL. Results are presented showing the system to be effective and robust.