A method for measuring urban road subsidence based on optical images

Urban road settlement is one of the key indicators for its safety warning. In the project, the road settlement observation point consists of a hollow cylindrical protective sleeve and a settlement rod on the center axis of the cylinder. This paper proposes an urban road settlement measurement method based on optical images. Firstly, the ellipse detection algorithm is used to identify the circular orifice features of the settlement monitoring point, and the angle between the camera and the road surface is recovered by the pixel size information of the ellipse long and short axes; secondly, the template matching algorithm is used to sub-pixel locate the diagonal features at the top of the settlement bar; finally, the settlement measurement model is established. On this basis, an urban road settlement measurement application (Easy-to-Go) based on Android platform was developed. The experimental results show that the measurement accuracy of the proposed method is better than 1mm, which meets the engineering measurement requirements. The research results of this paper can provide a convenient, low-cost and reasonable accuracy new method for road settlement measurement.