[4] [4] Jiyan, Zhang, et al. Metrological Research on Test Method for Phoropters［C］∥International Conference on Electronic Measurement & Instruments. Xi'an,China:IEEE,2007:423-426.

[7] [7] Elsayed, Mahmoud & Sammani, Fawaz & Hamdi. Optical power measurement using image processing techniques［J］. 2018,205-208.

[9] [9] Salas-Peimbert, Didia Patricia, et al. Simple Hartmann test data interpretation for ophthalmic lenses［J］. Review of Entific Instruments,2006,77(4):043102-043102-5.

[12] [12] Macqueen J. Some methods for classification and analysis of MultiVariate observations［J］. Proceedings of Berkeley Symposium on Mathematical Statistics & Probability,1965,14:281-297.

[14] [14] N Otsu. A threshold selection method from gray-level histogram［J］. IEEE Trans. Syst. Man. & Cybern,1979,9:62-66.