Rail straightness detection method based on the cooperation of dual laser sensors

•A high-precision line laser sensor measurement method.•Contains a fast location and redundant data exclusion algorithm.•Threshold filter and smoothing applied for noise issues.•A reverse estimation method is used to eliminate systematic errors. The surface straightness of the rail affects the accuracy of the rail welding process and the train safety. A dual non-contact sensor joint measurement method for rail straightness was proposed including a new sensor scanning layout, a fast-positioning algorithm for rail characteristics, and a noise filtering method composed of multiple methods. Equipped with high-precision line-structured laser sensors for measuring, this method improves the capacities of data process and industrial computer storage. The method filters out a large amount of useless data through an algorithm for fast target location to retain only a tiny amount of data for straightness measuring and defect positioning. For surface reflection and light interference problems in the measurement process, the impact of interference is reduced through filter algorithms and improvement of the sensor installation layout. Because of the impact of vibration and noise in the measurement process, threshold filtering and smoothing methods are used to process the data to ensure the accuracy of the results. Given the influence of the error of the sensors' scanning trajectory, reverse estimation is used to correct it. Compared with similar measurement methods, ours has advantages of almost the same measurement accuracy, better measurement certainty, lower cost, and faster positioning speed.