ADDITIONAL INFORMATION SUPERIMPOSING METHOD, ADDITIONAL INFORMATION DETECTION METHOD, ADDITIONAL INFORMATION SUPERIMPOSING DEVICE AND ADDITIONAL INFORMATION DETECTOR

摘要

PROBLEM TO BE SOLVED: To superimpose additional information so as to more surely and quickly detect the additional information of higher importance in the case of superimposing the plural pieces of the additional information of different importance on image signals as electronic watermark information. SOLUTION: A first PN generation part 5, a first additional information generation part 6, a second PN generation part 7 and a second additional information generation part 8 are controlled by timing signals generated in a timing control part 4. A ratio occupied by a superimposing area where the electronic watermark information SS1 of the first additional information of high importance generated in the first additional information generation part 6 is superimposed is made more than the ratio occupied by the superimposing area of the electronic watermark information SS2 of the second additional information of low importance generated in the second additional information generation part 8 and the electronic watermark information of the first and second additional information is superimposed on the image signals.