关键词: 双远心镜头, 机器视觉, 面阵CCD相机, 高速线材

Abstract: A high precision wire diameter measurement simulation 
system is designed, which is composed of parallel light source, double telecentric lens, CCD camera and 
object to be tested. Considering that this experimental system is designed to simulate the photography 
and measurement of high-speed wire, the radial velocity of wire rod can be as high as 100 m/s in the 
rolling process, and there are signs of transverse runout. Therefore, in the optical design, 
a telecentric lens with a fixed magnification rate is used to keep the image size on photosensitive 
surface unchanged when the distance is changed. Moreover, the maximum exposure time of the selected 
plane array CCD can reach 1$\mu$s, thus a high-definition image reflecting the size of the measured 
object can be obtained in real-time. The experimental results show that the diameter accuracy of 
the workpiece measured by the simulation system can reach 20 um, which can meet the needs of production.

Key words: double telecentric lens, machine vision, plane array CCD camera, high speed wire