A novel method is presented to estimate the distance between the railway and the poles alone the railway in one image based on the edge extraction of the poles. It has three main parts which are poles and the railway detection

poles classification and distance estimation. In the image with distortion and complex background

how to effectively and accurately detect the edges of the target is a crucial and difficult issue for image understanding and pattern recognition. This paper presents a robust straight-line extraction algorithm to solve this problem. This algorithm can extract the exact straight line edges of interesting target in the image with distortion and the complexity of scenes based on a fuzzy threshold and line fitting. The three main steps of the algorithm are edge detection

corner detection and the straight-line fitting based on fuzzy threshold method. The experimental results on real images demonstrate that the straight-line extraction algorithm we proposed is superiorly accurate and effective

and the distance estimation method is effective.