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

IPC: G06F12/14 ,  G06F21/24 ,  G06T1/00 ,  G09C5/00 ,  H04N1/32 ,  H04N1/387 ,  H04N7/08 ,  H04N7/081

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.