Laser-based detection and depth estimation of dry and water-filled potholes: A geometric approach

In secondary Indian roads, one often encounters potholes which can be either dry or water-filled. Accordingly, to ensure safe driving, it is imperative to detect potholes and estimate their depths in either condition. In this paper, we develop a physics-based geometric framework, where such detection and depth-estimation can be accomplished using suitable laser. Specifically, we relate dry pothole depth to measured optical deviation using simple ray optics. Further, we use Snell´s law of refraction to obtain a quartic equation, and its appropriate real root to relate water-filled pothole depth to the corresponding optical deviation. Here we take into account diminishing resolu- tion with increasing distance from the camera. We conclude by experimentally validating our method.