“…This gloss cannot be represented by mixing normal color inks. a) Correspondence to: imaizumi@chiba-u.jp * Graduate School of Science and Engineering, Chiba University 1-33 Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan * * Institute for Global Prominent Research, Chiba University 1-33 Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan * * * Graduate School of Engineering, Chiba University 1-33 Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan * * * * Software Design Department, MIMAKI ENGINEERING CO., LTD. 2182-3 Shigeno-otsu, Tomi-shi, Nagano 389-0512, Japan Data hiding techniques have been widely studied in the information security field for protecting the copyright of digital images [1][2][3][4][5][6][7][8][9][10][11][12]. The main purpose of data hiding is to prohibit malicious copying and secondary use without permission by embedding the copyright information into the images.…”