Wilailak, Krisada, Theerapan Raruenrom, Pathreeya Thanisaro, and Dr. Thanachart Numnonda. 2013. “A Comparative Study of Automatic Thresholding Techniques”. Engineering and Applied Science Research 23 (1):1-14. https://ph01.tci-thaijo.org/index.php/easr/article/view/8075.