Audio and image (including video) content data is watermarked by processes that take into account human perception attributes of the content. Some methods assess the input content data to discern inherent biases, and tailor the watermarking to exploit such data characteristics. Other methods make use...http://www.google.com.au/patents/US20010019618?utm_source=gb-gplus-sharePatent US20010019618 - Watermarking methods and media
