A method for extracting center-lines of structured light stripes in process of dimension measurement of large forgings

It is difficult to measure the dimension of hot large forging accurately in forging process because of the high temperature and poor measuring conditions.Accurate dimension measurement of hot part is very important to improve productivity and reduce scraps during hot forming process.Based on the image acquiring method of hot forgings,binocular structured light system is used to measure the dimension of hot large forgings on-line.Thus,the center-lines of structured light-stripes should be extracted by eliminating other kinds of structured light reflected by hot large forging.A method for extracting the center-lines of structured light-stripes from the single image of hot large forging is proposed.According to a certain threshold,the initial locations of structured light stripes and other kinds of light stripes are determined along a line in the row direction.The cross section of structured light stripe usually obeys the Gaussian distribution,so other kinds of light stripes can be eliminated by searching along the light stripes.Once the start points of light stripes are located in the image,the subpixel centers of structured light stripes can be calculated by searching along the light stripes.Experimental results show that this method is convenient and stable,and can efficiently extract the center-lines of structured light stripes which are projected on the surface of hot large forgings.