A Robust Method for Semi-Automatic Extraction of Road Centerlines Using a Piecewise Parabolic Model and Least Square Template Matching

This article reports on a study that used a semi-automatic road extraction method based on a piecewise parabola model with 0-order continuity. The piecewise parabola model is constructed by seed points coarsely placed by a human operator. In this situation, road extraction actually becomes a physical problem of solving of each piece of parabola with only two or three unknown parameters by using image constraints. The authors used a least square template matching to solve the parabola parameters. The template is deformable and based on the automatic detection of dual road edges. In addition, a method of flexible observation weight evaluation has also been developed in this matching method. The results of tests on various image sets show that the method is able to extract road centerlines robustly and efficiently, including centerlines with sharp turns. In addition, this method offers much higher efficiency compared to the manual digitizing process. The authors conclude with a discussion of semiautomatic road extraction and future work for improving the reliability and extending the availability of these methods.