(54) APPARATUS FOR AND METHOD OF
EMBEDDING AND EXTRACTING DIGITAL
INFORMATION AND MEDIUM HAVING
PROGRAM FOR CARRYING OUT THE
METHOD RECORDED THEREON
(75) Inventors: Hisashi Inoue, Fukuoka (JP); Shiro
Iwasaki, Iizuka (JP); Mikio Shimazu,
Kasuya (JP); Shuichi Ojima, Fukuoka
(JP); Takashi Katsura, Fukuoka (JP);
Akio Miyazaki, Fukuoka (JP); Eiichi
Hatae, Fukuoka (JP)
(73) Assignee: Matsushita Electric Industrial Co., Ltd., Osaka (JP)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/186,375
(22) Filed: Nov. 5, 1998
(30) Foreign Application Priority Data
Nov. 7, 1997 (JP) 9-306098
Jul. 10, 1998 (JP) 10-196361
(51) Int. CI.7 G06K 9/36; G06K 9/46
(52) U.S. CI 382/232; 382/251
(58) Field of Search 382/232, 203,
382/276, 279, 284, 100, 251; 380/40, 41, 51, 54; 375/240
(56) References Cited
U.S. PATENT DOCUMENTS
5,416,606 A * 5/1995 Katayama et al 358/467
6,175,639 Bl * 1/2001 Satoh et al 382/100
6,185,312 Bl * 2/2002 Nakamura et al 382/100
FOREIGN PATENT DOCUMENTS
EP 0 766 468 4/1997 H04N/7/08
JP 9-191394 7/1997
JP 10-124673 5/1998
JP 10-191330 7/1998
An apparatus for embedding information in a signal includes a band dividing device, a block divider, a quantization portion, a signal replacement portion, a mean difference addition portion, a mean calculation portion, and a band synthesis portion. The band dividing device divides the signal into transform coefficients over a plurality of frequency bands. The block divider divides one frequency band into a plurality of blocks in accordance with a previously determined block size. The quantization portion calculates for each block, a mean value M of the transform coefficients in the block, and subjects the mean value M to linear quantization, using a previously determined quantization step-size Q to calculate a quantization value. The signal replacement portion replaces the quantization value for each block, on the basis of the quantization value and the value of the information to be embedded. The mean difference addition portion subjects the replaced quantization value, for each block, to inverse linear quantization using the quantization step-size Q to calculate a mean value M', and adds a difference DM between the mean value M' and the mean value M to all the transform coefficients in the block. The mean calculation portion calculates a mean value LM of the transform coefficients in the frequency band after the addition of the difference DM. The band synthesis portion reconstructs a signal in which the information has been embedded using the frequency band after the addition of the difference DM and the other frequency bands.
18 Claims, 34 Drawing Sheets
