Abstract: In the production process of medium and heavy plates, the edge parts of plates often present irregular shapes. These irregular areas are generally unsuitable for further processing or application and need to be accurately cut off. To improve shearing efficiency and accuracy, an intelligent cut-to-length technology for segmented shearing of medium and heavy plates, which combines machine vision and PLC control, has been proposed.Firstly, the camera is accurately calibrated using Zhang Zhengyou's calibration method, and the spatial positional relationship between the camera and the shearing machine is determined. Then, the RGB color values of the image are extracted and further converted to the HSV color space, so that the image features are effectively extracted, and thus the endpoints of the plate head are accurately identified. Moreover, the distance between the endpoints in the world coordinate system is calculated by means of pixel coordinate conversion.When it is detected that the width of the plate head is stable and the number of endpoints is two, the system automatically determines that it is the regular position of the plate head. Subsequently, the system calculates the distance from the edge point of the length-measuring laser line to the regular position, so as to determine the target shearing position. The target position is sent to the PLC control system, and the roller table is controlled by the PLC to complete the shearing action.This intelligent fixed-length technology not only improves the accuracy of plate end-point recognition,but also significantly enhances the shearing accuracy and product quality, with the fixed-length accuracy controlled within ±5 mm.