(12) United States Patent ao) Patent No.: us 6,768,709 B2
Carson et al. (45) Date of Patent: Jul. 27,2004
(54) HIDING DIGITAL DATA IN A DIGITAL AUDIO OR VIDEO CARRIER SIGNAL
(75) Inventors: Douglas M. Carson, Cushing, OK
(US); Henry B. Kelly, Stillwater, OK
(73) Assignee: Doug Carson & Associates, Inc.,
Cushing, OK (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 631 days.
(21) Appl. No.: 09/792,163
(22) Filed: Feb. 23, 2001
(65) Prior Publication Data
US 2001/0024420 Al Sep. 27, 2001
Related U.S. Application Data
(60) Provisional application No. 60/184,232, filed on Feb. 23, 2000.
(51) Int. CI. G11B 7/00
(52) U.S. CI 369/53.21; 369/275.3
(58) Field of Search 369/53.21, 59.12,
369/59.13, 30.27, 30.04, 47.48, 47.49, 47.45, 275.3, 275.1, 59.19, 47.19, 59.27; 386/94,
(56) References Cited
U.S. PATENT DOCUMENTS
4,228,326 A 10/1980 Dakin et al.
An optical disc in which hidden data are stored for forensic tracking or copy protection purposes. This disc includes a contiguous user data portion comprising a set of user data samples which, when accessed by a readback system, generates a human detectable output. The disc further includes a null zone adjacent the contiguous user data portion comprising a sequence of user data fields storing a set of user data samples which, when accessed by a readback system, generates an output with a specified signal to noise ratio so as to be substantially undetectable by a human, wherein hidden data are written to at least selected ones of the user data fields of the null zone to convey a specified informational message related to the optical disc, the specified informational message undetectable by a human when the null zone is accessed by the readback system.
8 Claims, 5 Drawing Sheets