A new A-star algorithm adapted to the semi-automatic detection of cracks within grey level pavement images

The detection of cracking on the road surface is an important issue in many countries to insure the maintenance and the monitoring of the roadways. This paper proposes a method which adapts the single pair shortest path A* algorithm to the detection of cracks within pavement images. The proposed A* algorithm computes the crack skeleton by calculating the minimal path between a pair of pixels which belong to the crack structure. Compared with the widespread and ubiquitous Dijkstra's algorithm and to its bidirectional version, the proposed A* reduces the amount of the visited pixels; it is thus about 4 times faster than Dijkstra while keeping a large similarity coefficient with the ground truth.