Patent ID: 6731774
Filing Date: 2004-05-04
Classification: G06T

Abstract:
An information detecting apparatus in which a watermark pattern and an image are checked with each other for every small region made of verticalÃ—horizontal=MÃ—N (M and N are respectively a positive integer) pixels of a part of the image, information is embedded as a watermark in the image on the basis of the watermark pattern, and the information is detected from the image constructed by applying resolution conversion or picture frame conversion to the image embedded with the information, the information detecting apparatus comprising:arithmetic means for converting the watermark pattern correspondingly to the resolution conversion or picture frame conversion, performing checking against the watermark pattern made to correspond to at least a part of an encoded block in the image subjected to the resolution conversion or picture frame conversion, and calculating an evaluation value on the image; and judging means for comparing the evaluation value with a predetermined threshold value and judging whether the watermark is added; wherein the arithmetic means omits an arithmetic operation of the evaluation value in a case where a ratio of correspondence between the converted watermark pattern and the encoded block in the image subjected to the resolution conversion or picture frame conversion is smaller than a predetermined ratio.