A glass thickness measuring system using the machine vision method

摘要

This paper describes a measuring device of glass thickness using machine vision and image processing techniques on realtime sampling process. Recently, the machine vision enables to inspect fast and exact solution than human’s eyes. This system has advantages of continuous measurement, flexible and high accuracy in production line. The system consists of a laser diode, a CCD camera with PC. The camera located on the opposite side of the incident beam measures the distance between two laser beams which are reflected from the glass top and the bottom surface. We applied a binary algorithm to convert and analyze the image from the CCD camera to PC. A laser point coordinating method by border tracing algorithm is used to find out the center of laser beam circle. The measured result was compared with the one by a precision micrometer and showed as less than 0.005mm accuracy. Finally, the measurement errors were discussed how to minimize the influence of glass wedge angle and angular positioning errors of the glass moving stage.