Study Of Enhancement Algorithm Of Line-structured Laser Image For Shafts

In the era of intelligence,Mechanical Manufacturing Industry advances higher requirements for techniques of machine parts measurement.Shaft is the important part of mechanical structure,and its diameter measurement with high efficiency and high precision by using machine vision technology plays a significant role in the intellectualization of Mechanical Manufacturing Industry.In the line-structured lasers visual measurement of shaft diameter,the shaft with smooth surface,which is affected by its reflection characteristics,often has the problem of poor image quality so that the problem seriously affects the measurement accuracy.To tackle the problem,this paper proposes an enhancement algorithm of the images of line-structured lasers,which is based on Lambert diffuse reflection model.The experiment of this paper show that the enhancement algorithm can effectively improve the measurement accuracy of the smooth shafts.Firstly,this paper analyzes the differences and relationships between the linear imaging model and the nonlinear imaging model of the camera,and selects Zhang’s two-step method to calibrate the parameters of camera.In addition,the calibration technology of the optical plane of line-structured lasers,the calibration technology of the center line of the shaft and the fitting algorithm of the shaft diameter used in this paper about visual measurement of shaft are also introduced in detail.Secondly,the world coordinate system of shaft diameter measurement is established,and three common detection methods of center points of line-structured lasers are introduced.On this foundation,different detection algorithms of center points are used to detect images of line-structured lasers with different quality,and the detection accuracy is evaluated.It is proved that the image quality of line-structured lasers will have an important impact on the accuracy of measurement of shaft diameter.Thirdly,taking Lambert diffuse reflection model as the ideal reflection model of shaft,the paper analyzes the relationship between incident light intensity and image gray value.According to solving the world coordinates of light source point,reflection point and camera,the light reflection model of shaft surface is established,and the criterion of replacing the real gray value with the theoretical gray value is determined.Based on the criterion of gray replacement,an enhancement algorithm of the quality of line-structured lasers’ image is proposed.Finally,to verify the effectiveness of enhancement algorithm,the experimental platform is built and the experimental process is designed in this paper.Comparing the actual size of the shaft and the visual measurement results before and after the enhancement of line-structured lasers’ image,it is proved that the algorithm can improve the shaft diameter measurement accuracy of the smooth shaft.And other factors affecting the shaft diameter visual measurement accuracy are also analyzed.For the visual measurement of the shaft with smooth surface in engineering,the research content of this paper has certain value.