3-D radar imaging of buried utilities by features estimation of hyperbolic diffraction patterns in radar scans

The paper describes a processing method to extract hyperbolic patterns generated by the time-of-flight variation in Radar scans due to buried utilities. The method is capable to determine processing parameters by using only Radar settings available in the header of the raw data files. The apex position and the velocity of hyperbolic arcs both with positive and negative phases are estimated. After a confidence assignment of the hyperbolic patterns is calculated and the false alarm rejection rate is achieved by using multiple features. A probability of false alarm (Pfa) lower than 8 false alarms per linear meter with a probability of correct detection (Pd) greater than 95% has been obtained with a full data set from a road survey. The reliable estimation of buried utilities positions has been exploited with a tracking algorithm to reconstruct a 3D topographic mapping of the investigated site. In this way it is much improved the difficult and time consuming task of the human operator to decide the buried utility path according to multiple B-scan and stratigraphic images analyses.