Patent ID: 7970164
Filing Date: 2011-06-28
Classification: G06T,H04N

Abstract:
1. A digital watermark detection method in a digital watermark detection apparatus for detecting a digital watermark from moving images, comprising: a moving image input step, at the digital watermark detection apparatus, of sequentially obtaining a frame image by moving image input means; a difference image generation step, at the digital watermark detection apparatus, of generating, by difference image generation means, a difference image between the currently obtained frame image and a previously obtained frame image; and a digital watermark detection step, at the digital watermark detection apparatus, of performing, by digital watermark detection means, digital watermark detection from the difference image to output a digital watermark detection status, wherein, in a case where digital watermark detection process is continued including a case where previous digital watermark detection is impossible, the moving image input means obtains a new frame image again so that each of the above steps is repeated, the moving image input step including a step of sequentially obtaining the frame image and frame display time that is a display time of the frame image, the digital watermark detection method further comprising: a determination step, at the digital watermark detection apparatus, of determining detection necessity based on a time interval between the current frame display time and frame display time of the previously obtained frame image using watermark pattern switching information used when embedding a digital watermark, wherein, when it is determined that detection is unnecessary in the determination step, the moving image input means obtains a new frame image again, and when it is determined that detection is necessary, processes after the difference image generation step are continued.