关键词: 珍珠, 图像获取, 缺陷检测, 自由落体, 对比度增强, 区域生长, 形态学, ,

Abstract: To overcome the special problems in images grabbing and defects detection of pearl，a dome-shaped light source with diffused light illumination is designed in this paper to improve image quality and reduce light-spot size.And a novel quasi-synchronous multi-images grabbing scheme from different views is proposed based on pearl’ free falling motion.A new nonlinear filter based on space geometry was designed to enhance defect contrast and region-grow method is then used for extracting all suspicious defects，including highlight-halation regions.Furthermore，the highlight-halation regions are removed using morphological method based on the special distributive model of the highlight-halation.At last，shape and texture features of defect regions are extracted to describe different defects.Experiments show that the acquired images included the complete information of pearl surfaces and extracted features could effectively implement the defect detection of pearl surfaces.

Key words: pearl, image acquiring, defect detection, free falling, contrast enhancement, region grow, morphology