Pipe localization by apex detection

Ground penetrating radar is used to scan the shallow subsurface for detecting buried objects like pipes without corrupting the road surface. Buried objects are represented by hyperbola branches on GPR radargram images. As the manually interpretation of such radargrams is expensive and time consuming, an important goal in this field is to automatize the pipe localization process. A novel approach which is able to automatically estimate the number of buried objects, their horizontal position and their depth from a radargram is presented in this paper. Additionally, this approach delivers the reflection patterns of the buried objects, which may help to estimate their material. The core of our method is a specialised clustering algorithm which detects apexes with appendant hyperbola branch shaped clusters and ignores noise. A hyperbola fitting algorithm delivering hyperbola parameters is applied to this clusters. The pipe locations are estimated by means of the clusters found and the apexes of the fitted hyperbola branches.