Research on image recognition and detection method of sapphire bubbles

摘要

Sapphire crystals are used in the manufacture of LEDs, optical window materials, etc. The presence of air bubbles in the crystal affects the optical properties of the material. If the position of the bubble is determined, the bubble can be bypassed for subsequent slicing to obtain pure high quality sapphire crystal. At present, the detection and identification of bubbles in sapphire crystals still rely on human eye observation and empirical judgment, which is inefficient and easily harmful to the human eye. It is necessary to propose a highly efficient method of machine vision detection instead of human eye detection. Based on the machine vision detection technology, this paper uses the laser as the light source to enter the ingot from the bottom, which produces the laser scattering effect. With this effect as the imaging principle, the image is collected by CCD. The image is analyzed by image processing means to achieve detection of bubbles, this paper proposes and elaborates the following two steps: edge detection based on edge pixels and locking the target area based on the calibration connected domain. The experimental results show that compared with the human eye detection method, the detection method greatly improves the detection rate and accuracy of identifying the bubble in the sapphire and determining its position.