[1] [1] MALLAT S, HWANG W L. Singularity detection and pro-cessing with wavelets［J］. IEEE Transactions on Informa-tion Theory, 1992, 38(2): 617-643.

[6] [6] HAN B. Watershed segmentation algorithm based on morphological gradient reconstruction［C］//The 2nd International Conference on Information Science and Control Engineering, 2015: 533-536.

[8] [8] PENG H, ZHAI R F, LIU S M, et al. Edge detection of growing citrus based on self-adaptive Canny operator［C］//The International Conference on Computer Distributed Control and Intelligent Environmental Monitoring, 2011: 342-345.

[9] [9] DENG C X, WANG G B, YANG X R. Image edge detection algorithm based on improved Canny operator［C］//The International Conference on Wavelet Analysis and Pattern Recognition, 2013: 168-172.

[10] [10] LU J Y, PAN H, XIA Y M. The weld image edge-detection algorithm combined with Canny operator and mathematical morphology［C］//Proceedings of the 32nd Chinese Control Conference, 2013: 4467-4470.

[11] [11] SONG R J, GAO X D. The Canny operator based on the study of the method of image text location［C］//International Conference on Multimedia Technology, 2011: 5591-5593.