<p>An input image is distorted so that it has less correlation to a watermark and the distorted image is subtracted from the input image to provide a preprocessed image. If the correlation between the preprocessed image and a watermark is sufficient then the watermark is detected in the input image. The distortion may be a spatially-variant distortion such as stretching, shrinking, shearing or rotation or the distortion may be a non-linear transforming or filtering such as median, local minimum or local maximum filtering.</p>
申请公布号
EP1046141(B1)
申请公布日期
2003.06.04
申请号
EP19990952609
申请日期
1999.10.18
申请人
KONINKLIJKE PHILIPS ELECTRONICS N.V.
发明人
OP DE BEECK, MARC, J., R.;HAITSMA, JAAP, A.;DEPOVERE, GEERT, F., G.;KALKER, ANTONIUS, A., C., M.