-
公开(公告)号:JPH10164349A
公开(公告)日:1998-06-19
申请号:JP31610596
申请日:1996-11-27
Applicant: IBM JAPAN
Inventor: NINOMIYA SHOICHI , MORIMOTO NORISHIGE , TEZUKA TSUDOI
Abstract: PROBLEM TO BE SOLVED: To provide high durability against elimination or change of hidden message information by hiding medium information into message information in a frequency space and to keep hidden message information effectively even when signal processing using a frequency filter is executed. SOLUTION: In order to hide message information (m) in medium information M, these information are frequency-converted to obtain those frequency spectra f1 , f2 . Then an area including a characteristic frequency component denoting a characteristic of the message information (m) in a real space is extracted from the frequency spectrum f2 of the message information (m) as a basic area B. Regarding the basic area B, n-sets of copies are generated and n-sets of the copies are arranged dispersedly in the frequency space and the other frequency components are set to zero to generate a frequency spectrum f3 as intermediate information. Finally the frequency spectrum f3 and the frequency spectrum f1 are added and the result is frequency-converted inversely to hide the message information (m) into the medium information M.