A robust method to extract a laser stripe centre based on grey level moment

Extraction of a laser stripe centre from an image is one of the most important measurement procedures when using structured light techniques. However, due to the influence of noise, extracting a light stripe centre accurately and stably remains a challenging problem. In this paper, a robust laser stripe centre extraction method is proposed. The method involves two steps: First, a closed-form solution for extracting the centre from every transversal section of a laser stripe is derived based on conservation laws of grey level moment. Second, a smoothing spline algorithm is used to determine a continuous curve of centre points. This algorithm can eliminate noise and maintain the original features of the discrete points. In the experiment, the proposed method is compared with recently reported techniques by detecting the same image. The results demonstrate that the method is more accurate and robust in the presence of noise.