Takao Nakamura Atsushi Katayama Masashi Yamamuro Noboru Sonehara Fast watermark detection scheme for camera-equipped cellular phone. 101-108 2004 MUM http://doi.acm.org/10.1145/1052380.1052395 conf/mum/2004 db/conf/mum/mum2004.html#NakamuraKYS04