Regional adaptive histogram equalization using fuzzy sets. - Koichi Ogawa; Atsuhisa Saito; Masato Nakajima; Yutaka Ando; Shozo Hashimoto (Image Processing, 1990)

Optimum contrast enhancement using fuzzy sets. - Atsuhisa Saito; Masato Nakajima; Koichi Ogawa (Syst. Comput. Jpn., 1991)