Hiroshi Fujii Hideki Sakamoto Sachiko Irie Hiroyuki Yamashita Watermark Resolution. 2001 conf/icmcs/2001 ICME http://csdl.computer.org/comp/proceedings/icme/2001/1198/00/11980082abs.htm db/conf/icmcs/icme2001.html#FujiiSIY01