Study Of On-Line Thickness Detection Technoligy And System For High Temperature Glass

The development of on-line glass thickness measurement in high environment is pressing problem to float glass production line. In the paper we covered a topic of in-line glass thickness measurement in high environment, and the computer vision technology was studied as well.The noncontact optical measuring technique can be divided into optical reflection and transmission measurement. The reflective-type optical measurement systems for on-line measuring the thickness of glass are the most common products used in the industry. Based on the optical design of the astigmatic theory, a high accuracy thickness measurement system for glass was developed, in which measurement errors caused by glass tilting and shaking and high temperature were tackled as crucial issues.Firstly, high temperature characteristics of tin bath and the actual production of float glass were analyzed and thickness detection mechanism were elaborated. Astigmatic optics theory were employed. For the good relationship between the focus error signal (FES) and the glass thickness variance, a mathematical model was found.Secondly, the whole on-line glass thickness detecting system was designed and key technology was studied. Glass tilting and shaking of the impact of thickness measurement were analyzed. this design has a significant advantage that the system can manipulate and reduce the influence of glass tilt by exploiting the central position of FES. This design can improve the precision of measurement without errors compensation system.Thirdly, The effect of high temperature environment on industrial vision detecting system was studied. Errors was brought by the change of the size of glass and other performances variety after heated, by the light source in high temperature and detector and by the bending of light resulted from the change of air density in measurement were experimental analyzed, and then the error compensation methods were present.At last, experimental research and analysis have been completed. The main experiment include light source angle of incidence and thickness measurement and results analysis.