1. ZHENG C H, HUANG L, TANG W, et al. Research on pearl shape and size detection system based on image processing [J]. Journal of China University of Metrology, 2014, 25(3): 258–262 (in Chinese).
2. HUANG L, ZHENG C H, ZHOU M L, et al. Research on pearl shape and thread detection system based on image processing [J]. Science and Technology Innovation Herad, 2014, 11(8): 65–66 (in Chinese).
3. LI Y H, LU Z Y, LI T J. New pearl shape symmetry detection algorithm [J]. Computer Engineering and Applications, 2012, 48(24): 37–40 (in Chinese).
4. ZHENG H W, CAO Y L, YANG J X. Separation method for shape grading of pearls using computer vision [J]. Journal of Engineering Design, 2008, 15(5): 365–368 (in Chinese).
5. UNAY D, GOSSELIN B, KLEYNEN O, et al. Automatic grading of bi-colored apples by multispectral machine vision [J]. Computers and Electronics in Agriculture, 2011, 75(1): 204–212.